1.1.1 The Identification of Animal Materials

Before there was any formal scientific analysis of animal materials, humans gained experience with the properties of skeletal tissue through enacting technical practices for the creation of worked objects. The formalized scientific study of animal materials has its roots in the Scientific Revolution of the sixteenth and seventeenth centuries. Antonie van Leeuwenhoek, famous for revolutionizing the single-lensed microscope, published observations on the microstructure of bone and tooth. His description and illustration of the structure of elephant ivory notes the similarity of the material to “platted work” and appears to be the earliest depiction of one of the most diagnostic features of proboscidean ivory (van Leeuwenhoek Reference van Leeuwenhoek1678, 1003). By the nineteenth century, biologists, chemists, anatomists, and other researchers were studying the composition of biological organisms on a microscopic level.

Bernhard Schreger (Reference Schreger1800) performed some of the early work on the structure of teeth, describing banded growth patterns within enamel. While these patterns are rarely seen within worked animal objects, his line of inquiry was influential for other researchers studying the structure of teeth. Following Schreger, Anders Retzius (Reference Retzius1837) was one of the earliest scholars of the microstructure of the teeth of multiple animal species, also observing the distinct crisscrossing bands of elephant tusk that was described by van Leeuwenhoek. Biologist and paleontologist Richard Owen (Reference Owen1856) also identified and illustrated this pattern in proboscidean ivory within his later work Ivory and the Teeth of Commerce. In the early nineteenth century, Thomas Franz Hanausek (Reference Hanausek1907) published comparative studies of the microstructure of a series of animal materials, providing illustrations of features like the dentinal tubules of ivory.

Thomas K. Penniman (Reference Penniman1952), the anthropologist and curator of the Pitt-Rivers Museum at the University of Oxford, was one of the first scholars to publish a comparative guide of animal materials using photography, greatly advancing the study of these objects. Since Penniman’s work, several journal articles and guides have been published on different aspects of animal material structure. With the ratification of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1973 and the subsequent bans on elephant ivory, there was a pressing need for government agencies to have a clear means of differentiating animal materials. The CITES identification guides provided further high-quality images and definitions of specific structures within animal teeth.

However, the CITES guides and Penniman’s publication show modern animal materials or worked objects in pristine condition, so there have also been several works explicitly aimed at archaeologists and scholars of material culture. Olga Krzyszkowska’s (Reference Krzyszkowska1990) Ivory and Related Materials primarily focuses on animal materials found within the Mediterranean region, but her guide to differentiating types of ivory is cited across archaeological subfields. Similarly, Arthur MacGregor (Reference MacGregor1985) provides a detailed overview of the structure of animal materials, as well as background on the production processes used by craftspeople in the past (especially those in Europe during the post-Roman period). While there is a long history of the study of durable osseous materials, the more ephemeral remains of keratinous materials have not received the same attention. However, since the 1980s, Sonia O’Connor (Reference O’Connor, Starling and Watkinson1987, Reference O’Connor, Solazzo and Collins2015) has explored methods of identifying archaeological examples of keratinous materials using visual and scientific analysis.

1.1.2 The Study and Interpretation of Worked Animal Objects

As a result of the development of prehistoric archaeology in Europe (specifically France) in the nineteenth century, objects made from animal materials were an important part of early archaeological scholarship. Jacques Boucher de Crèvecœur de Perthes’ (1788–1868) discoveries of stone tools in the Somme valley eventually led to the acceptance of his ideas about the age of humanity. Subsequent early scholars inspired by de Perthes, such as Vicomte Alexis de Gourgue and Gabriel de Mortillet, studied the stratigraphic distribution of objects made from animal materials; De Mortillet’s (Reference de Mortillet1873, 436) classification of the chronology of the Paleolithic was based, in part, on the presence of bone and antler tools. Opposed to de Mortillet’s chronological reasoning, Henri Breuil (Reference Breuil1907, see also Davies Reference Davies, Hosfield, Wenban-Smith and Pope2009) also used stratified bone tools as evidence to establish the sequence of the Paleolithic period. By the early twentieth century, the importance of bone tools in the study of the Paleolithic period provided an environment for scholars to produce work focused on tools made from animal materials during this era (e.g., Chauvet Reference Chauvet1910).

While research on worked animal materials was becoming more common in the twentieth century, the emphasis on the study of stone tools in prehistoric archaeology resulted in some of the largest theoretical advances. These new perspectives led to a focus on the technological process and detailed typologies of tool types (e.g., Bordes Reference Bordes1961). André Leroi-Gourhan used the study of lithics to develop the idea of the Chaîne opératoire, a heuristic that schematizes sequences of technological acts and seeks to reconstruct mental actions and technical gestures related to the purpose of creating, using, and discarding objects (see Sellet Reference Sellet1993). A parallel idea, known as the reduction sequence, was also being developed by American scholars (see Shott Reference Shott2003). While these ideas were initially applied to stone tools, the Chaîne opératoire was subsequently adopted by scholars researching other forms of technology, and it has remained a major influence on the study of worked animal objects.

Important developments in the study of lithics and animal materials also occurred outside France. S.A. Semenov’s (Reference Semenov1964) research is an example of how the study of lithics and bone and antler tools often occurred in tandem. Semenov originally published Prehistoric Technology in Russian in the USSR in 1957, before it was translated into English in 1964. While its reception outside Russian-speaking academic circles was limited, it offered a new methodology focused on recognizing the traces of tool use and understanding the function of tools. Semenov’s approach emphasized experimentation as a means of understanding modifications and became the basis for a methodology known as use-wear analysis. Subsequent research on worked animal materials, such as Douglas Campana’s (Reference Campana1989) publication of bone tools from the Zagros and the Levant, explicitly draws on Semenov’s approach to use-wear analysis. Since Campana and Semenov’s publications, archaeological studies of worked animal objects continue to rely on use-wear analysis by incorporating technologies like SEM microscopy and 3D modeling.

In the 1970s, the study of tools made from osseous materials became a more distinct subfield of prehistoric archaeology, with the first international symposium on prehistoric bone industry organized by Henriette Camps-Fabrer. As a result of these meetings, Camps-Fabrer created the Committee of Nomenclature of Prehistoric Bone Industry, a series that aimed to explore and classify different types of osseous objects (e.g., wind instruments, barbed points, and ornaments), and which led to a series of publications lasting from the 1980s until the 2000s.

Outside of prehistoric archaeology, scholarly emphasis on worked animal materials occurred in countries with long traditions of zooarchaeological research. Working in Hungary, Alice Choyke and László Bartosiewicz researched and published assemblages of worked animal materials originating from a variety of different time periods; their subsequent work also included studies of worked animal objects from other parts of Europe, Anatolia, and the Near East. During the 1990s, Choyke was integral in establishing the study of worked animal objects as a more distinct subfield within archaeology. In 1997, worked animal objects became a focus of the International Council for Archaeozoology (ICAZ), when the inaugural conference of the Worked Bone Research Group (WBRG) was held at the British Museum. Since the second meeting, the WBRG has held biennial conferences in locations around the world, and publications of these proceedings began in 2001. While so much of the previous scholarship on worked animal materials was rooted in specific regions or time periods (often prehistoric Europe), the WBRG represents the work of scholars with different temporal and cultural specializations. In the introduction to the proceedings of the second meeting, Choyke and Bartosiewicz (Reference Choyke and Bartosiewicz2001, III) describe the mission of the WBRG, writing that “an effort was made to present these papers on the basis of what connects them rather than segregating them by archaeological period or region.”

Owing to the focus on tool use in prehistoric archaeology, much of the scholarship on worked animal materials has tried to understand the function of such objects. Methodological studies like use-wear analysis aim to reconstruct how craftspeople used tools in the past. However, major theoretical shifts such as the post-processual critique of New Archaeology have changed how scholars approach material culture. Moreover, zooarchaeology has also begun to move away from interpretations of faunal assemblages that exclusively view the material through a lens of economy and subsistence. As a result, the way scholars approach and present worked animal objects is changing. Recent theoretical perspectives throughout anthropology, archaeology, and the social sciences more generally (e.g., actor-network theory, the ontological turn, materiality studies, human–animal studies, and the incorporation of indigenous perspectives) have begun to influence how scholars think about animal materials (e.g., McNiven Reference McNiven2010; Conneller Reference Conneller2012; Isaakidou Reference Isaakidou2017).

2.1.1 Long Bones

Among most animals, long bones are typified by a hollow shaft (diaphysis) surrounded by cortical bone, with two ends (epiphyses) mostly made up of spongy, trabecular bone. Long bones store marrow within the diaphysis in a structure known as the “medullary cavity.” When cut transversely, long bones show the medullary cavity as a hollow portion (Figure 5). Four long bones (humerus, femur, tibia, and radius) bear a significant portion of the animal’s weight, are critical for movement, and are generally thicker and stronger than other elements. The concentration of dense cortical bone, as well as the regular shape, made long bones an appealing material for craftspeople. The tubular structure of long bones was well-suited to objects like musical instruments, tool handles, rings, and pyxides. Additionally, the long, straight sections of cortical tissue contained within long bones allowed for the creation of objects like points, needles, and spoons.

Figure 5 View of the transverse surface of an object made from a ruminant metapodial from the site of Hasanlu in Iran (ca. ninth century BCE). (A) Trabecular bone; (B) typical shape of a ruminant metapodial; and (C) cortical bone.

Source: Metropolitan Museum of Art, accession number: 60.20.27.

Craftspeople often removed the epiphyses and altered the shape of the diaphysis, making identification of the specific element or species exceptionally difficult. However, regions of certain long bones can be diagnostic and identifiable. In many taxa, the proximal shaft of the tibia appears triangular in cross section. The diaphysis of the humerus tends to be thicker than other long bones, which may aid in identification. The fibula and ulna are narrower than the other long bones, resulting in the use of these elements for objects like awls or small points. The ulna articulates with the radius and humerus within the forelimb of the animal, and its shape naturally tapers toward a pointed distal end (known as the styloid process). As a result, craftspeople often modified the distal ends of the ulna to create pointed tools. Fibulae are fairly variable among different species and can be nearly absent or much smaller than the other long bones. In bovines, the fibula exists only as a small region of bone fused to the proximal and distal ends of the tibia. Equids possess a fibula that is shorter than the tibia, while the fibula is robust among pigs and other suids. Owing to the slender shape of this skeletal element, examples of needles and other thin points made from fibulae are known throughout the world. Points made from pig fibulae are relatively common in European assemblages, but fibula from very different species have been used for similar tools as well; there is an Australian tradition of creating points from kangaroo fibulae that began in the Pleistocene era (Langley et al. Reference Langley, O’Connor and Aplin2016).

Long bone shafts were a rich source of material for worked animal objects, but craftspeople also made use of the proximal and distal ends as well. For example, the head of the humerus (the part of the proximal end that articulates with the scapula) is round and even, making it an ideal material for an object like a spindle whorl (Arabatzis Reference Arabatzis and Vitezović2016). As objects made from the epiphyses are composed primarily of trabecular bone, they exhibit a spongy appearance.

2.1.2 Metapodials

The metapodials are located immediately proximal to the bones making up the digits of the animal (Figure 6); these bones are called metacarpals in the forelimbs and metatarsals in the hindlimbs. The number of metapodials differs among species and depends on the method of locomotion and number of digits. Ruminants that walk on hooves composed of two digits (e.g., cattle, cervids, sheep, and goats) have metapodials that begin as separate bones and fuse during infancy. Animals that have hooves composed of a single digit (e.g., equids) have one metapodial that bears the weight of the animal and is similarly robust. However, equids also have smaller, styloid-shaped metapodials (often called “splint bones”) that are located on both sides of the weight-bearing metapodial. The morphology and size of metapodials differ among animals that walk on their toes or on the soles of their feet. These species generally have more digits, corresponding to greater numbers of smaller sized metapodials. Despite the small size, there are examples of worked objects made from the metapodials of these species (Choyke et al. Reference Choyke, Vretemark, Sten, O’Day, Neer and Ervynck2004, 187, fig 18; Luik Reference Luik2012, 95, see fig. 4.3).

Figure 6 Forelimbs of mammals with different numbers of digits.

Source: Drawing by Leah Olson, after (Reitz & Wing Reference Reitz and Wing1999, 59, fig. 3.14).

The metapodials of ruminants and equids have served as popular elements for creating worked objects across different cultures and time periods for several reasons (see Schibler Reference Schibler1981, 21; Zhilin Reference Zhilin1998; Schibler Reference Schibler, Menotti and O’Sullivan2012, 341; Choyke & Tóth Reference Choyke, Tóth, Anders and Kulcsár2013, 339). Like long bones, these bones are also exceptionally thick and straight, offering large portions of cortical bone that can be turned into a variety of objects. The fusion process leaves behind a channel following the length of the bone (sulcus) which provided craftspeople a means of splitting the bone along the longitudinal axis (see Section “Splitting Techniques”). The smaller metapodials of equids (i.e., splints) have much less bone, but craftspeople could use them to create points (Russell Reference Russell and Hodder2005, 341, fig. 16.2). Additionally, the metapodials are generally regarded as contributing less to the diet than other elements because there is very little meat surrounding these bones, often leading to them being discarded. However, the parts of the animal considered appealing or useful in dietary practices are socially constructed, and metapodials can be a valuable source of marrow. As a result, the relationship between the dietary value of an element and its use as a raw material may not be the same in all cultures.

Identifying the elements used to create a worked bone object can often be difficult, but recognizing examples of worked ruminant metapodials is possible due to the distinct morphology of the bones. The initial fusion of the metapodials results in a bifurcated appearance visible in cross section; in transverse cross sections nearer to the proximal and distal ends, the metapodial appears separated by a thin portion of bone (Figure 1). In examples of worked animal objects where the interior of the diaphysis is unaltered, the remains of the fusion process may offer clear evidence for the use of a ruminant metapodial.

2.1.3 Flat Bones

Composed of a thin layer of cortical bone surrounding a core of trabecular bone, flat bones include the ribs, the scapula, the bones of the pelvis, and a number of the bones of the cranium (classified separately here). Worked examples of the ribs and scapula are found more commonly in the archaeological record, while examples of modified pelvis bones are comparatively rare. The ribs of many mammals are relatively flat, making them an ideal material for an implement like a spatula, scraper, thresher, or similar tool. Craftspeople also used a longitudinal splitting technique to create tool handles by separating the rib into two halves and attaching the bones to a metal or stone implement (Hamilton & Nicholson Reference Hamilton and Nicholson2007).

The scapula resembles a rough triangle and is so thin in certain species that it appears partially translucent. Owing to its unique shape, the scapula had many uses in the ancient world: scapulimancy (see Section “Flat Bones”), digging implements (Xie et al. Reference Xie, Lu, Sun and Huang2017), threshing tools (Medina et al. Reference Medina, López and Buc2018), and hide and fiber processing tools (Hofman Reference Hofman1980). Incised scapulae have also been found throughout the ancient Near East and Anatolia, and while the interpretation of these artifacts varies, it is thought that they may have functioned as musical instruments (Zukerman et al. Reference Zukerman, Lev-Tov, Kolska-Horwitz and Maeir2007; Koitabashi Reference Koitabashi2013). The scapulae of larger animals could also be useful in the production of other objects: A whale scapula recovered from a well in the Athenian Agora exhibited use wear, indicating it was used as a working surface (Papadopoulos & Ruscillo Reference Papadopoulos and Ruscillo2002) and mammoth scapulae found at the Kostyonki–Borshchyovo archaeological complex were dug into the ground and used as surfaces for craft production (Semenov Reference Semenov1964, 171, fig. 87).

2.1.4 Axial Skeleton

The axial skeleton (i.e., the spine) is made up of several types of vertebral bones. The two bones closest to the cranium are known as the atlas and axis, which provide support for the skull. Following these elements are a series of different types of vertebrae: cervical, thoracic, lumbar, sacral, and caudal. Vertebrae have a high proportion of trabecular bone, as well as thin and breakable sections. Additionally, butchering practices often split or break vertebrae. For these reasons, the vertebrae of most mammals were not commonly used by craftspeople, although there are modified examples thought to be early expressions of symbolic thought (Majkić et al. Reference Majkić, d’Errico, Milošević, Mihailović and Dimitrijević2018; Ardelean et al. Reference Ardelean, Arroyo-Cabrales and Rivera-González2023). The vertebrae of larger animals served as a valuable material for a variety of cultures. A bowl made from a whale vertebra was found at the Neolithic site of Skara Brae (Orkney Islands of Scotland; Childe et al. Reference Childe, Paterson and Bryce1929, 274, fig. 34). Similarly, minimally modified whale vertebrae were found at the Phoenician colony of Motya on Sicily (ca. sixth–fifth century BCE) in association with Murex shells, suggesting that these bones were used as a working surface for dye production (Reese Reference Reese2005). While worked mammalian vertebrae are generally rare, the vertebrae of fish and sharks were commonly used to create objects like beads (see Section “Fish Bone and Cartilage”).

2.1.5 Sesamoids, Carpals, and Tarsals

These elements are grouped together because they are small, and worked examples are rare within the archaeological record. The limited recovery of such objects may be a function of practical or cultural selection processes that did not favor the use of small bones encased in connective tissue. Additionally, factors related to taphonomy, preservation, and excavation methods may also bias against the recovery of these smaller elements. Sesamoids are spherical bones located within tendons, the largest of which is the patella. There is little evidence for the modification of sesamoids beyond that of the patella (Hahn Reference Hahn1972, 260–263).

Carpals are a collection of small bones located between the metacarpals and the radius/ulna, while tarsals are found between the metatarsals and the tibia/fibula. Like sesamoids, worked carpals and tarsals are rare apart from one large tarsal bone: the astragalus. The astragalus is roughly rectangular in shape, with four faces that are similar in size. The bone can be thrown like a die and land on one of its four sides. As a result, the astragalus was used as a gaming piece, as well as a divination tool for astragalomancy. These properties make the astragalus one of the most widely studied and common worked animal objects across cultures and time periods (Gilmour Reference Gilmour1997; Affanni Reference Affanni, Córdoba, Molist, Pérez, Rubio and Martínez2008; Carè Reference Carè2025). The astragalus is colloquially known as a “knucklebone,” most often in reference to its use in games; certain publications continue to use this term. Semenov (Reference Semenov1964, 175–176) notes that carpals and tarsals of mammoths found at Mousterian-period Kosh-Koba in Crimea were used as anvils for craft production. Examples of worked carpals and tarsals from smaller species are significantly rarer, although an example of a worked carpal or tarsal of a turtle was found in a midden in south Florida (Walker Reference Walker, Marquardt and Payne1992, 239, fig. 12).

2.1.6 Bones of the Skull

The skull is made up of the mandible and a series of fused elements of the cranium, including the frontal, parietal, and occipital bones. The cranial bones can be oddly shaped, irregular, and difficult to separate, potentially making them a less desirable material for craftspeople. Nevertheless, examples of worked cranial bone are found within the archaeological record (Boardman Reference Boardman1967, 211, no. 600, pl. 97). Additionally, the medieval trade in walrus ivory spawned an artistic practice of carving the part of the animal’s skull known as the rostrum (maxilla, frontal, and nasal bones). Mandibles, especially those of large animals, were more commonly used within the creation of worked animal objects (Barrett et al. Reference Barrett, Khamaiko and Ferrari2022). For example, cattle mandibles were used as smoothing tools at Middle Bronze Age sites in Hungary (Choyke & Schibler Reference Choyke, Schibler, St-Pierre and Walker2007, 59–60). The ramus (the region of the mandible between the teeth and the rest of the skull) provides a flat surface that was also used by craftspeople wishing to make items like discs or buttons (MacGregor Reference MacGregor1985, 61, fig. 36; Klippel & Price Reference Klippel, Price, St-Pierre and Walker2007, 111, fig. 10).

2.1.7 Phalanges

The phalanges are the bones that make up an animal’s digits (e.g., fingers, hoofs, and flippers). Like long bones, most phalanges have proximal and distal ends and a small diaphysis in the center, although the distal phalanges (equivalent to the tip of the finger or the toe) usually come to a more pointed end because they do not articulate with any other bones. Distal phalanges can also be covered in a keratinous plate (i.e., fingernail), hoof, or claw. One of the most common modifications of phalanges is the creation of claw pendants; craftspeople who made such pendants often created a suspension hole through the proximal end of the distal (usually third) phalanx, which was often still attached to the keratinous portion. As keratin is highly susceptible to decomposition (see Section 4), usually only the modified bone preserves. In addition to claw pendants, there are several examples of worked phalanges in archaeological contexts that were seemingly chosen for the unique shape of the bone and appear to have symbolic uses (Pawłowska & Baranski Reference Pawłowska and Barański2020, 8; Leder et al. Reference Leder, Hermann and Hüls2021). Additionally, there are also examples of worked phalanges that have ambiguous functions and often referred to as “toggles” (St-Pierre et al. Reference St-Pierre, Needs-Howarth and Boisvert2021, 241). It is likely that some worked phalanges actually functioned as clothing fasteners, while others may have been gaming pieces (e.g., Bläuer et al. Reference Bläuer, Hukantaival, Saarinen, Hirvilammi and Ratilainen2019) or other types of objects.

2.2.1 Avian Bones

Due to the requirements of flying and the unique morphology of avian species, the bones of birds differ from those of mammals in several ways. Birds possess some skeletal elements which are absent in mammals. These differences are especially prevalent in relation to the elements located in the wings and feet; birds possess different forms of metacarpals, metatarsals, carpals, and tarsals. While this may seem like a minor distinction, certain cultural groups used these unique bones to create worked objects. Cultural groups on New Guinea often used the tibiotarsus and the tarsometatarsus (akin to a tibia and metatarsus) of the cassowary bird to create daggers (Dominy et al. Reference Dominy, Mills, Yakacki, Roscoe and Carpenter2018). Some of the skeletal elements shared by birds and mammals are also morphologically different. The proximal end of an avian humerus is relatively flat and elliptical, hardly resembling the comparable structure in mammals. Additionally, relative size of certain elements may differ between birds and mammals; for example, the avian sternum is comparatively larger than the same element in mammals.

The inner structure of this type of bone represents one of the most consequential differences between mammalian and avian species. It is often said that bird bones are hollow, and thus lighter to assist with flight. It is more accurate to describe bird bones as covered in a thin layer of cortical bone, with concentrations of trabecular bone at the ends. Avian trabecular bone is markedly more open than that of mammalian bone, with large hollow pockets. The shafts of avian bones are the hollowest portions, with “struts” of trabecular bone which form intermittently throughout. These features make avian bones feel significantly lighter and more delicate than other mammalian bones. These features made them appealing to craftspeople for specific uses (e.g., the creation of musical instruments). Objects made from the birds of bones should feel lighter than objects made from mammalian bones of a comparable size. However, there are a host of taphonomic processes that contribute to demineralization and degradation of mammalian bones. Therefore, the most effective way to recognize worked animal objects made from bird bones is to develop a general understanding of avian skeletal anatomy.

2.2.2 Turtle Shell (Carapace and Plastron)

The shell of the turtle (reptiles from order testudines including terrapins, tortoises, and sea turtles) is an osseous structure covered in keratinous scales called “scutes.” The top of the shell is called the carapace, while the bottom is known as the plastron. “Turtle shell” should not be confused with “tortoiseshell,” the name given to a keratinous material made from the scutes of sea turtles (see Section 4.3). Turtle shell is akin to flat bone, as it has a trabecular core surrounded by two layers of cortical bone. Additionally, the elements of the turtle shell are joined together “at soft unmineralized collagen sutures” (Achrai & Wagner Reference Achrai and Wagner2013, 5891). Craftspeople using turtle shells took advantage of its shape to create rounded objects that incorporated this structure. Archaeological examples of musical instruments made from turtle shells (e.g., rattles) have been found across the United States (Gillreath-Brown Reference Gillreath-Brown2019). Similarly, the ancient Greek lyre (chelys) was made from a turtle shell, examples of which have been found in several archaeological contexts (e.g., Kokkoliou Reference Kokkoliou2020). There is also some evidence for craftspeople carving smaller pieces of turtle shell to create implements or tools (e.g., Hull Reference Hull2018, 945, fig. 16). Pieces of the carapace and plastron are easy to identify within archaeological assemblages because they feature prominent suture lines. The shell frequently breaks along these sutures, resulting in rectangular or hexagonal pieces surrounded by wavy, jagged edges. Due to the suture lines, shell is often mistaken for cranial bones of humans or other mammals. However, turtle shell has a heavily ridged exterior which is rougher than cranial bone.

2.2.3 Marine Mammal Bones

The exploitation of marine resources, whether through hunting or scavenging, has afforded humans access to the skeletal material of marine mammals. Owing to the requirements of swimming in a saline environment, marine mammals evolved to have denser bones than those of terrestrial mammals, making them an appealing material for craftspeople. As whale habitats are widely distributed across the major oceans, these animals have served as important resources (e.g., meat, oil, and bones) for a variety of cultures around the world. Whale bone served as a particularly useful material for craftspeople in the past. It should be noted that the “whale bone” under consideration is separate from the keratinous material baleen, which is sometimes referred to as “whalebone” (see Section 4.2). The earliest evidence for the modification of whale bones comes from Upper Paleolithic period sites in the northern Pyrenees (Pétillon Reference Pétillon2013), and the practice of carving whale bones continued into the modern era with the development of scrimshaw in the eighteenth and nineteenth centuries. Craftspeople often sought out the flat, dense sections of the mandible (referred to as the “pan bone”); the large size and uniquely flat shape of these sections of the jawbone makes objects made from this section of the skeleton identifiable as whale bone. Owing to the immense size of whales, craftspeople also had the ability to carve large sections of whale bone without leaving features to identify a particular skeletal element. Nevertheless, it is often possible to identify whale bone owing to the unique morphological properties of the material.

Whale bone is composed primarily of trabecular tissue, surrounded by a thin layer of cortical bone. Unlike the bones of other mammals, whale bones lack a medullary cavity, meaning that there is no hollow section that the craftsperson had to incorporate in their carvings. This material afforded craftspeople the opportunity to create large objects, carving every surface without having any hollow sections. The size of the bones, combined with the lack of medullary cavity, can make whale bone relatively easy to recognize after it has been modified. Additionally, trabecular whale bone looks different than either the trabecular or cortical bone of terrestrial mammals. Trabecular whale bone has a dense appearance similar to the cortical bone of terrestrial mammals; however, it is speckled with trabeculae that are not overly clustered. The overall appearance is that of markedly grainy cortical bone. Crucially, the trabecular bone is remarkably homogeneous throughout the skeleton. Jean-Marc Pétillon (Reference Pétillon2013, 528) describes the structure of whale bone, writing: “[W]ith few exceptions, the trabeculae are rather evenly distributed, and they never indicate a ‘spongy’ side or end opposed to a ‘compact’ one; they can be seen on all sides of the objects and across their entire length.” Certain elements are an exception, as the ribs and vertebrae of whales exhibit more concentrated areas of trabeculae that appear similar to the same elements in terrestrial mammals. Moreover, objects made of whale bone may still intersect both the outer cortical layer and the inner trabecular tissue, resulting in a more heterogeneous appearance overall. In addition to whales, there is also archaeological evidence for the modification of the bones of bottlenose dolphins (van den Hurk et al. Reference van den Hurk, Riddler, McGrath and Speller2023, 148) and walruses (Barrett et al. Reference Barrett, Khamaiko and Ferrari2022). The bones of these species exhibit similar features, which can complicate the differentiation among marine mammal skeletal materials.

2.2.4 Fish Bone and Cartilage

The skeletons of bony fishes (osteichthyes) are made up of a set of cranial (larger and more diagnostic) and axial bones (smaller vertebrae and spines). The bones of fish differ from those of mammals, reptiles, and birds, making it easy to differentiate them within the faunal assemblage. The cranial bones are relatively flat, such that they often exhibit a degree of translucency, and the vertebrae of the axial skeleton are round with spiny processes. Cartilaginous fish (Chondrichthyes) exhibit similar anatomy, but the skeletal elements are made up of cartilage rather than bone.

There are many barriers to the identification of fish remains: The preservation of fish bones is highly dependent on the conditions of the burial environment, and systematic studies necessitate proper recovery techniques (e.g., sieving and flotation). These factors similarly impact the recovery of worked animal objects made from the bodies of fish. As a result of these factors, fish bone artifacts appear to be less common than other types of worked animal objects, although it is unlikely that the rarity of these objects is a result of issues of preservation and recovery alone. The remains of fish were unlikely to have been a favored material for craftspeople in the past, as the bones are generally small and brittle, making modifications difficult.

Regardless, craftspeople still created a range of objects from different skeletal elements of bony and cartilaginous fish. In many cases, craftspeople created objects from the skeletons of fish by making only small modifications to an element. The vertebrae of fish served as a popular material for the creation of beads and other similar objects because the central portion of this element is exceptionally round and relatively easy to perforate; fish vertebrae are so naturally even that unworked examples are often mistaken for finished objects. Similarly, the fin spines of certain types of fish (e.g., catfish) offered craftspeople a naturally serrated point that could be modified into a tool (e.g., Hull Reference Hull2018, 945, fig. 16). A similar approach was used for the non-bone elements of cartilaginous fish; stingray spines are naturally blade-like extensions of the skeleton which held high symbolic value in certain cultures (Haines et al. Reference Haines, Willink and Maxwell2008) and were sometimes worked to create points or blades (e.g., Wake Reference Wake and Arnold2001, 187, fig. 9.5). Additionally, certain fish possess a set of teeth that sits within a part of the lower jaw called the pharyngeal plate. These teeth are denser than fish bone, and are composed of enamel and dentine like the teeth of mammals. Pharyngeal teeth could be lightly modified and worn as a form of adornment, with evidence for this practice found in Mesolithic sites in the Upper and Lower Danube regions (Cristiani et al. Reference Cristiani, Živaljević and Borić2014, 304).

In addition to this technological approach, in which craftspeople adapted the natural shape of the skeletal element to create an object that was similar in shape, there are also instances of craftspeople making significant modifications to fish bones: A chess piece carved from the cranial bone (cleithrum) of a haddock was found at Siglunes in Iceland (Lárusdóttir et al. Reference Lárusdóttir, Roberts and þorgeirsdóttir2012, 22). Additionally, species of sturgeon have rows of bony scales known as scutes that were also modified by craftspeople; archaeological examples have been found in Estonia (Jonuks & Rannamäe Reference Jonuks, Rannamäe, Livarda, Madgwick and Mora2018, 170. fig. 12.3). Scutes generally have a diamond or kite shape, with an underside that resembles trabecular bone.

3.2.1 Color

The word “ivory” is synonymous with a creamy shade of white typical of the material when it is fresh, yet a variety of factors can affect the color of dentine, including sunlight, acidity, and changes in temperature or humidity. While ivory and dentine are understood to be synonymous, craftspeople regularly incorporated cementum and material from the the cementum-dentine junction into their carvings. As a result, ivory objects will often have regions of different colors, which can become more pronounced in the burial environment (Figure 11). Additionally, subjecting ivory to excess temperatures can alter the color of the material. Ivory exposed to heat can take on shades ranging from bluish gray to black. As a result, color does not provide a reliable metric for determining whether an object is made from ivory, although it may be beneficial for differentiating different tissues within the tooth (e.g., enamel, dentine, and cementum).

Figure 11 (A) Ivory fragment showing a transverse cut with a thick layer of cementum. Schreger pattern is faint closest to the cementum layer. (B) Detail view of the Schreger pattern presenting as a “checkerboard.” (C) Detail view of the Schreger pattern. (D) A longitudinal surface of delaminated ivory (the “ghosts” of lamellae). (E) Transverse view of degraded ivory showing faint lines of lamellar growth (F) Detail of ivory carving showing longitudinal surface of delaminated ivory (the “ghosts” of lamellae).

Source: A, B, D, E: Photos by Jeff Vanderpool. Photos courtesy of the Ephoreia of Antiquities of Pieria and UCLA. C: Detail of an ivory spoon from Central Africa (late 1800s–early 1900s) from the Cleveland Museum of Art, accession number 2010.449. F: Detail of Levantine ivory carving from the Cleveland Museum of Art, accession number: 1968.46.

3.5.1 Cementum

Unlike in the teeth of other species, cementum covers nearly the entirety of the outside of proboscidean tusks. The material is thickest at the proximal end, but present throughout the tusk. Cementum exhibits ridges that run parallel to the length of the tusk (Figure 13A), although the ridges can also appear less pronounced (Figure 13B). Unlike dentine, cementum lacks indications of concentric growth and is not made up of dentinal tubules, so diagnostic patterns like the Lines of Owen or Schreger lines are absent. It can, however, become delaminated from the dentine at the Cementum-Dentine Junction. Within the context of proboscidean ivory carving, cementum has been referred to as “bark,” and sometimes carvers removed the material (Stern Reference Stern2007, 27). However, there are many examples of finished ivory objects that retain regions of cementum. As it was more likely to be discarded, the presence of cementum (or pieces of ivory retaining cementum) in an archaeological context may be an indication of an ivory production space.

Figure 13 Ivory production waste from ancient Methone (ca. 700 BCE). (A): Cementum of an elephant tusk showing cut marks; (B): degraded piece of cementum of an elephant tusk showing cut marks.

Source: Photographs by Jeff Vanderpool.

3.5.2 Dentine

The dentine of proboscidean tusks is found underneath the outer layer of cementum. It occupies most of the incisor and follows the same curved shape of the tusk. As in the teeth of other species, the pulp cavity occupies roughly the first third of the tusk (the proximal region). The pulp cavity exhibits a similar shape to the tusk itself: a conical region tapering toward the distal end. While ivory carvers needed to be conscientious of the hollow region of the tusk, the amount of dentine within the distal portion of larger tusks could have provided craftspeople enough material to create works which do not incorporate the pulp cavity. Additionally, craftspeople could remove rectangular sections of ivory from around the pulp cavity as well. As a result, plaques and smaller sculptural works will not necessarily show any sign of the pulp cavity. Owing to the incremental growth processes of proboscidean dentine, there are a series of diagnostic features that can help identify the material.

3.5.3 Schreger Pattern

One of the most distinct characteristics of ivory is a series of light and dark regions present on transverse sections of the tusk. Scholars have associated multiple scientists with the discovery of this pattern (including Schreger, Retzius, and Owen), which has led to some confusion about its name. This pattern is most often described as “Schreger lines” or “Schreger pattern” even though Schreger did not actually observe elephant teeth, and the patterns he described were within enamel rather than dentine (For an overview of the term, see Espinoza & Mann Reference Espinoza and Mann1993). Additionally, the term “Hunter-Schreger Bands” is widely used in dental histology and refers specifically to the enamel bands. Some scholars describe this ivory pattern as the “Lines of Retzius,” as Retzius described the phenomenon within elephant teeth. However, there is a separate term within dental histology known as the “Striae of Retzius,” which describes growth lines within enamel (rather than dentine). It should also be noted that there is a different pattern related to concentric growth within ivory described as the “Lines of Owen” (See Miles & White Reference Miles and White1960, 778). While Owen was one of the first to document the Schreger pattern, the “Lines of Owen” should not be understood as equivalent to the Schreger pattern. While few initially adopted the use of the term “Schreger pattern,” it has become widespread among scholars and non-scholars alike. As a result, this work acknowledges the contributions of the other researchers (e.g., Retzius and Owen), but will continue to use the term “Schreger pattern” for clarity.

The Schreger pattern often appears as a series of interconnected V-shaped bands known as Schreger or “engine-turned” lines. As this pattern is unique to proboscideans, it is considered one of the best metrics for characterizing ivory. When illustrating Schreger lines, most guides will provide an image of a cross section of modern tusk. Such images clearly display the pattern, but they are not always helpful for identifying archaeological materials. As worked ivory objects were carved from a variety of orientations within the tusk, the transverse surface may not be evident on every archaeological specimen. Additionally, the Schreger pattern is less pronounced in certain areas of the tusk, including the regions nearer to the cementum-dentine junction and the region closest to center of the tusk (Figure 11A). Even if the archaeological object captures a transverse section of ivory where the Schreger pattern should be visible, the preservation environment has a marked effect on the coloration of the surface and appearance of the pattern. As a result, the Schreger pattern may appear as the typical series of pronounced V-shaped lines, faint lines, or even as a checkerboard (Figure 11A–C). While the Schreger pattern is one of the best criteria for establishing whether an object is made from proboscidean ivory, both the preservation and orientation of the carving can affect whether it is present.

The Schreger pattern also offers a quantitative basis for determining the species of proboscidean to which the ivory belongs. A series of studies have demonstrated that different proboscidean species have distinct ranges of angles of intersecting Schreger lines. Ivory from mammoth species exhibits acute Schreger angles ( $<{90}^{\circ }$ ), whereas extant species tend to show larger angles. Additionally, the Schreger angles of Asian elephants appear consistently smaller than those of African elephants. The outer Schreger angles, those located nearer to the cementum, are larger than those closer to the center of the tusk (inner Schreger lines). Additionally, Schreger angles can vary depending on whether they are recorded closer to the proximal or distal end of the tusk. Moreover, many of the studies of Schreger angles have been conducted using large portions of ivory cut to a precise transverse section, allowing researchers to control for these variables. As a result, archaeological samples of ivory are not likely to give enough information to make an accurate determination about species.

3.5.4 Lamellae and Cone-within-Cone Splitting

The incremental layers of growth (lamellae) within proboscidean dentine are often visible to the naked eye and can be used to distinguish ivory from other materials (Figure 11E). However, detecting lamellae can often depend on both the condition of the ivory and the original orientation of the object within the tusk. The lamellae grow in increments, often giving dentine a banded appearance. This pattern, known as the “lines of Owen,” often co-occurs with a different diagnostic feature of ivory called “cone-within-cone splitting.” Cone-within-cone splitting is an effect of the tusk becoming delaminated around its regions of concentric growth, resulting in a series of regular cracks that run through the material. As this feature is thought to result from changes in humidity, cone-within-cone splitting may be more likely to occur in archaeological specimens than in more modern objects. Other animal materials may be prone to cracking, but cone-within-cone splitting has a shape and regularity that differentiates it from similar effects of deposition in other materials.

Within a transverse cross section of a tusk, cone-within-cone splitting will present as a series of circular cracks which radiate from the center, whereas a longitudinal cut shows cone-within-cone splitting as a parabolic set of cracks (Figure 14). As objects are not always carved from a portion of the tusk that is parallel to the longitudinal or transverse axis, cone-within-cone splitting may also appear as a series of elliptical lines. However, many ivory objects are carved so that their original orientation within the tusk is not immediately obvious, and cone-within-cone splitting will not necessarily occur throughout the entire object; detecting cone-within-cone splitting requires identifying multiple parallel cracks (Figure 15).

Figure 14 Back of a Levantine horse frontlet carved from longitudinal section of the elephant tusk showing parabolic cone-within-cone splitting (ca. ninth–eighth centuries BCE).

Source: Metropolitan Museum of Art, accession number: 61.197.5.

Figure 15 Levantine ivory carving showing deterioration typical of cone-within-cone splitting (ca. ninth–eighth centuries BCE). The right image shows highlighted sections of cone-within-cone splitting.

Source: Cleveland Museum of Art, accession number: 1968.46.

The longitudinal surfaces of delaminated ivory have a ridged appearance which Krzyszkowska (Reference Krzyszkowska1990, 90) refers to as the “ghosts” of lamellae (Figure 11 D and F). This feature is common in archaeological examples of proboscidean ivory due to cone-within-cone splitting, although hippopotamus ivory can also exhibit the same patterns (Banerjee et al. Reference Banerjee, Schuhmacher and Cardoso2017). As a result, the “ghosts” of lamellae should not be seen as a diagnostic trait of proboscidean ivory, but they can be used to distinguish ivory from bone or antler.

3.6.1 Pig and Boar

The lower canines of pigs and boars can most easily be distinguished by their distinct shape: a trihedral/triangular cross section. Two of the sides of the canine are covered in a thin layer of enamel, while the remaining side exhibits exposed dentine. The dentine exhibits a more uniform surface in both color and texture, while the enamel appears glossy, with a series of lunate ridges that occur in the transverse direction (perpendicular to the length of the tooth). Like the canine teeth of hippopotami, pig and boar canines possess a V-shaped interstitial zone that is visible in a transverse section.

On lower canines, the wear facet tends to be small and narrow, making up only a small portion of the total length of the tooth. Upper canines are slightly more curved than lower canines and have a bulbous rounded shape in cross section. The upper canines are likewise only partially covered in enamel, with a section of exposed dentine. The wear facet is significantly longer and wider, taking up a considerable portion of the length of the tooth. As so much dentine is exposed, the darker interstitial zone can often be seen as a black line running parallel to the length of the tooth within this region. Compared to other forms of ivory, the dentine of pigs and boars appears dense and homogeneous with only faint signs of growth lines (not always visible and best viewed with a flashlight).

People in the past approached suid canines in different ways; craftspeople often used these teeth as pendants, with little modification beyond a drill hole or attachment. However, Japanese netsuke carvers created designs in relief on the surface of suid teeth, often preserving the overall shape of the material. In a wholly different approach to the material, the Mycenaean Greeks used the canines of boars to create helmet plates. Rather than carve the dentine of the tooth, Mycenaean craftspeople created flat sections from the enamel while cutting most of the dentine away. In a strict sense, the enamel plaques cannot be called boar ivory, as most of the dentine was removed.

3.6.2 Warthog (Phacochoerus sp.)

Warthog canines are significantly larger than the canines of pigs and boars and can be as large as the teeth of hippopotami. In addition to differences in size, the canine teeth of warthogs are distinguishable from those of pigs and boars based on several morphological features. Owing to two longitudinal grooves that run the length of the tooth, the canine teeth of warthogs appear “waisted” or “pinched” at the center; the overall shape is also markedly rectangular (see Baker et al. Reference Baker, Jacobs, Mann, Espinoza, Grein and Allan2020, 51 and Figure 16). Unlike the homogeneous dentine within the canines of pigs and boars, the dentine of warthog canines exhibits visible growth lines. These dentinal layers surround a conspicuous interstitial zone that is straight, as opposed to the V-shaped interstitial zone that typifies the canines of pigs, boars, and hippopotami.

Figure 16 Drawing of a warthog canine tooth in cross section.

Source: Drawing by Leah Olson.

5.3.1 Incision

Incision involves the use of a tool (e.g., knife, gouge, and awl) to cut into the surface of the material to a limited depth. Incised lines differ in appearance: They can be straight or curved, carved freehand or with a fixed tool, and the depth of the incision varies depending on the object or craft. For example, scrimshanders incised very fine lines as a way of illustrating and shading scenes on the surfaces of whale teeth. The technique of incision was also used to create larger lines at a greater depth (see Figure 2). One of the most widespread motifs found on worked animal materials is the ring-and-dot pattern, which consists of an outer circle (ring) surrounding an incised or impressed circular region (dot). The ring-and-dot motif is achieved using a scribing tool, a pronged metal object that cuts into the material at a fixed radius. Craftspeople could use scribing tools of different sizes to create patterns with multiple rings enclosing the same central dot, a pattern akin to a “bullseye.” Compasses or scribing tools could also be used to create patterns of interconnected arcs, such as the guilloche pattern or the hexafoil motif. Figure 2 shows both incised lines and the ring-and-dot motif. The profile of incised lines may differ depending on what tool was used, but generally these lines present as a narrow, V-shaped or U-shaped valley. Additionally, this technique generally leaves behind the same amount of material on either side of the incised line.

5.3.2 Knapping

The process of knapping is a technique of breaking away sections of a material using a percussive tool. Knapping is strongly associated with lithic technologies, but a similar approach was also been used for animal materials. Knapped lithic materials have a series of distinct features, including the presence of a force cone and compression waves. When the knapper strikes the stone, the force propagates through the material in a wave, creating cone or bulb like formations. The flake is sheared away, often preserving ripples of force on the exposed surface (compression waves). Stone is very different from animal materials, meaning that knapping will not necessarily produce the same effects. However, these distinct visual characteristics have been detected among antler and ivory production waste at prehistoric sites in Europe and Asia (Heckel & Wolf Reference Heckel and Wolf2014; Girya & Khlopachev Reference Girya, Khlopachev, Christensen and Goutas2019, 326). Worked animal materials exhibiting rounded faces that were sheared away and which show lines of force radiating through the material in the form of small bands are evidence for knapping techniques. Knapping may also leave an archaeological signature in the form of the flakes of bone or antler that were removed. In their exploration of the production of antler objects found a rock shelter in France, Aline Averbouh and Jean-Marc Pétillon (Reference Averbouh, Pétillon and J. Baron2009) observed several flakes that were unworked and smaller than finished objects in the assemblage. They conclude that craftspeople at the site were knapping to sectioning the antler (“debitage by fracturation”). However, it can be difficult to identify bone and antler objects created through knapping, as a minimally worked tool created from a flake of bone will look very similar to other pieces of unmodified bone in the assemblage. Additionally, the potential for identifying “pseudo-tools” is high, as many processes result in the deposition of broken bones which are visually similar to tools that were purposefully made. Moreover, knapping may be an initial or intermediate step in the production process, after which subsequent actions (e.g., abrasion) may remove traces of this technique.

5.3.3 Splitting Techniques

There are a series of techniques that involve cutting a groove in the osseous material to create a fracture point. Subsequently, the craftsperson applies a force to separate the material in a controlled manner. Similar techniques appear in other technological traditions (e.g., lithic manufacture) and have been found across cultures and time periods. These methods have variously been referred to as “groove-and-snap,” “groove-twist-snap,” “cut-and-break,” as well as “chop-and-snap” techniques. Evidence for these techniques is often found among societies that relied primarily on stone tools, and these approaches appear to have been more economical than cutting through the material. However, there is no reason that metal tools could not have been used within these practices as well. Grooving methods can be applied to both the transverse and longitudinal axes, either as a means of preparing sections for subsequent modification or to remove undesirable portions of the animal material. When this technique is used along the transverse axis, such as around the base of an antler tine, the craftsperson may be able to break off the material using their hands. Snapping techniques along a transverse axis can leave a recognizable feature: a spur of material that juts out beyond the grooved surface. While this feature can be a diagnostic aspect of the technique, subsequent production actions (e.g., abrasion or polish) may obscure the broken surface. Grooving techniques along the longitudinal axis rely on the same principle. Evidence for a technique of creating points from the bones of small mammals and birds was found within assemblages in southern Louisiana. Based on experimental data, Dave Davis and collaborators (Reference Davis, Kidder and Barondess1983, 100) surmise that the craftspeople began by incising the shape of the point into the bone and then broke it by employing “major sheer stress” to the transverse axis while applying a “slight twist.”

Using small and pliable bones, it is possible to split longitudinal sections with bare hands. However, longitudinal splitting may also require a percussive force (e.g., a hammer, hitting the material against an anvil) to split the material. Alice Choyke and Zsuzsanna Tóth (Reference Choyke, Tóth, Anders and Kulcsár2013, 344) describe their experimental approach to splitting grooved metapodials, writing that “the action consists of gentle movements. The aim is to crack the bone along the prepared line with the chisel acting as wedge.” In this case, there is some overlap between the different actions, as Choyke and Tóth used the grooving tool to separate the bone. The “groove-and-splinter” technique also relies on creating fracture points, but it is used to extract longitudinal portions from a core of osseous material and is most strongly associated with Paleolithic antler objects (Clark & Thompson Reference Clark and Thompson1954; Semenov Reference Semenov1964, 155–158; Zhilin Reference Zhilin1998; Pétillon & Ducasse Reference Pétillon and Ducasse2012; Baumann & Maury Reference Baumann and Maury2013). Using this method, the craftsperson cuts parallel grooves into the material in the longitudinal direction. Subsequently, the craftsperson uses a tool to pry out the portion of the material between the parallel grooves. This technique produces long, straight sections of antler that can be subsequently worked into points.

5.3.4 Abrasion

Abrasion is the act of changing the shape or appearance of an object through extended contact with another material. One application of this technique involves moving the animal material over a coarse surface (e.g., stone) to level and smooth the material. This method was often used to create flat surfaces (e.g., scrapers), and the same technique was used to create a point from a series of angled surfaces. The points could be further refined by rotating the point against the coarse surface, creating a rounded tip. Unlike a cut surface, the abraded surface displays more obvious irregularities. Unless subsequently polished, abraded animal materials will display striations from the production action. If abrasion was used to create a flat edge (e.g., a scraper), the striations may be oriented in roughly the same direction. However, using abrasion to create a rounded point entails moving the material in multiple directions, changing the orientations of the striations.

Abrasive techniques are also used to polish animal materials: Softer materials like leather or fine sand can give worked animal objects a smooth and shiny surface. While worked animal objects often exhibit polish, this feature may be a deliberate technique of the craftsperson (Figure 27B) or the result of some other process. Objects that consistently come into contact with human hands (e.g., tool handles) can inadvertently become polished. Moreover, objects that are suspended or affixed by a rope or cord may also become abraded and polished through use; Figure 9 shows wear around the drill hole that originated from use. Using evidence of polish as criteria for determining whether an object is worked can also pose a challenge because the burial environment can abrade animal materials over time, making the material appear anthropogenically modified (e.g., Thorson & Guthrie Reference Thorson and Guthrie1984; Fisher Reference Fisher1995, 34–36). Polished surfaces are typified by a smooth feeling and a degree of shine, although taphonomic factors can also obscure these features.

Figure 27 Hellenistic bone carving of Dionysos. (A) Negative space created by carving. (B) Shine from polish. (C) Chisel marks showing circular pitting and striations on the cut surface. (ca. fourth–sixth centuries CE).

Source: Metropolitan Museum of Art, accession number: 1993.516.1.

5.3.5 Drilling

Drilling techniques represent a common means of perforating animal materials. The rapid rotation of a drill forms a hole by cutting into or abrading the animal material. Drills were often made from metal or stone but have also been constructed using other materials. Craftspeople may have also added abrasive materials like fine sand or emery powder during the drilling process. Drilling methods and technologies also varied between cultures and time periods, as innovations like the bow drill and pump drill allowed for faster and more constant motion. Different methods of drilling can result in holes that vary in appearance, although drill holes will often exhibit a uniform diameter throughout. Owing to differences in drilling techniques, there can be some uncertainty in determining whether a hole was made by a drill or other method. A uniform diameter is a strong indication that a hole was made by a drill, although variations in drilling techniques or the skill of the craftsperson might create uneven drill holes. Craftspeople wishing to perforate an animal material without a drill will often cut into the surface of the animal material from two sides, resulting in an hourglass-shaped perforation; holes made with this technique will generally show two uneven piercings that narrow toward the center.

Drilling can also serve as an extractive method to remove portions of material to be subsequently worked. Using a tubular drills, craftspeople can remove a section of the animal material, which might be turned into an object like a button or a ring. It can be difficult to identify finished objects created from a material that was extracted using a drill, as traces of the process might be completely obscured in the final product. The best evidence for the use of extractive drilling techniques is often only visible in the production waste; this waste might present as a piece of animal material with a series of circular holes (Bikić & Vitezović Reference Bikić, Vitezović and Vitezović2016). Craftspeople drilling into thicker skeletal elements might leave behind circular concavities which feature a spur of broken bone from the center.

5.3.6 Lathe

A lathe is a device that rapidly turns a material around an axis of rotation, allowing a craftsperson to remove small amounts of that material using a cutting tool. Lathes produce objects that are highly symmetrical about the axis of rotation, allowing craftspeople to create spherical, grooved, and tapered shapes. Determining whether a lathe was used to create an object can be challenging because this technique leaves behind ephemeral production waste that does not preserve within the archaeological record (i.e., shavings). Additionally, skilled craftspeople in the past were able to create symmetrical objects without using turning tools, so an even appearance is not necessarily a good indication of the use of a lathe. However, materials cut using a lathe tend to leave behind a series of regular striations resulting from cutting tools contacting the surface of the material; these marks are visible to the naked eye and perpendicular to the axis of rotation (see Figure 3). Lathes can also be used in association with abrasive methods to produce a high degree of polish.

5.3.7 Sawing

The technique of sawing involves using a tool in a back-and-forth motion to cut into an animal material; the cutting action either occurs in both directions or is unidirectional. Some sawing actions are primarily abrasive, using the surface of the tool and potentially an additional substance (e.g., fine sand, emery powder) to wear away the material. Using an abrasive method, experimental recreations of sandstone saws have been able to cut into a variety of materials, including whale bone (Kendig et al. Reference Kendig, Smith and Vellanoweth2010, 202–203). Additionally, experimental studies also demonstrated that using a string saw in conjunction with an abrasive substance was nearly as efficient as a serrated bronze knife for cutting into bone (Wang et al. Reference Wang, Campbell, Fang, Hou and Li2022, 9). Other types of saws have sharpened or serrated edges to cut into the material. Each movement of the sawing tool leaves striations on the surface of the animal material that are generally visible to the naked eye. When craftspeople change the orientation of the tool, the striations also change direction. Saw mark striations can be seen on Figures 1 and 25; Figure 1 shows changes in the orientation of the striations closest to bone spur on the example on the left. Saw mark patterns can be somewhat ambiguous, as changes in cutting orientation result in the striations intersecting at different angles. When an object exhibits an incomplete saw mark, it appears as a valley-shaped area that has a roughly even amount of material on either side (Figure 13A). Incomplete saw marks are valuable for understanding the production process, so researchers should attempt to describe their width and profile (e.g., V-shaped, rectangular) because these features will differ depending on the tool used.

Sawing actions can leave behind features that are separate from the cutting motion itself. When a craftsperson sawing through an object nears the end of the cut, the small amount of material remaining can break easily. Either the craftsperson chooses to snap away the last portion or the pressure on the material causes it to break apart. The result of this action is either a protruding spur or small concavity. In the left example of a cut metapodial in Figure 1, a small spur shows where the cutting action terminated. While the presence of spurs is associated with all techniques that involve snapping, small spurs on otherwise neat surfaces are strong indications of a cutting or sawing action.

5.3.8 Hacking or Chopping

As opposed to the controlled method of separating animal materials with a saw, hacking is the act of cutting into a material using a series of striking or chopping motions in which the blade is moved perpendicular to its cutting edge (i.e., an up-and-down motion rather than a side-to-side motion). Hacking or chopping actions can be completely perpendicular to the material (i.e., used to split a material in two parts). Alternatively, hacking or chopping motions can also be performed parallel to the surface, shearing off small amounts of material and leaving behind a flat cut surface. When hacking or chopping is performed with metal tools, this action can leave behind a flat surface or cutting plane that forms when the material is sheared away. In this case, the tool can leave striations on that cut surface that follows the direction of the striking action. As hack marks are usually achieved in a single motion, there is less variation among the direction of the striations on the cut surface. However, stone tools do not possess enough of a uniform edge to leave behind this sheared face. Experimental studies have shown that stone tools tend to cause “splintering and fragmentation on both sides of the chop” (Okaluk & Greenfield Reference Okaluk and Greenfield2022, 23). Moreover, all tools can cause a degree of crushing, a deformation of the animal material that often appears similar to other taphonomic processes. As a result, complete chop marks made with stone tools can be difficult to identify. However, Tiffany Okaluk and Haskel Greenfield (Reference Okaluk and Greenfield2022, 18) note that hack marks made with stone tools produced associated “peck marks,” areas of irregular deformation around the cutting surface. Depending on the angle of the cut, the size of the tool, and the nature of the material, incomplete hack marks made with metal tools can appear similar to an incomplete saw mark (i.e., valley-shaped), although signs of crushing or shearing are indications that the mark was made with a chopping action. Hacking or chopping can be a less controlled action, so there is a tendency for craftspeople to strike the material more than once, resulting in multiple marks at similar orientations. In Figure 9, there are a series of hack marks made at a slight downward angle. These marks have a series of sheared surfaces that show where the blade struck the material.

5.3.9 Scraping or Chiseling

Using a tool with a cutting edge like a knife, chisel, or gouge, the craftsperson can scrape the surface to remove material or create a flat face. These cutting actions are the result of the craftsperson applying consistent force parallel to the surface, altering the material without cutting too deeply. While sawing actions tend to leave behind obvious striations, scraping tools produce different types of marks. The cut surface can appear sheared, such as what occurs when a metal tool is used to chop. However, a chisel or similar tool may form small linear marks perpendicular to the cutting surface. These marks represent the results of the craftsperson attempting to apply consistent force to the cutting action. If the tool hits a thicker portion of the material and can not cut any farther, it will leave behind these linear marks (Figure 27C). Flat-cutting tools may also leave behind rounded marks that appear as small gouges within the material; such marks are visible in Figure 27 (Area marked C and elsewhere). Scraping or chiseling can also produce a distinct tool mark called “chatter.” Chatter is a result of a craftsperson applying too much pressure for the angle of the tool. If there is insufficient lubrication between the material and the tool, the material will vibrate from the force of the tool. As the material vibrates, the tool bounces off and strikes the surface periodically, creating a banded pattern. Chatter is marked by a strong regularity which may make them appear as though they were the result of a deliberate action. Chatter marks also tend to be shallow and may not be visible in all lighting conditions. The surface of the object in Figure 28 shows scraping or chiseling tool marks, including a small amount of chatter on the bottom half.

Figure 28 Antler fibula plate from ancient Methone, with and without raking light.

Source: Photographs by Jeff Vanderpool.

5.3.10 Carving

Carving is a reductive process, in which the craftsperson removes material to create a shape or design. As a result, carving might represent several different production techniques (e.g., drilling, incision, or the use of a knife), some of which may not leave any trace. Referring to an object as “carved” recognizes that the object underwent significant extractive-reductive techniques to create its current shape, meaning that it is really a composite of different techniques. Carving creates areas of negative space and is often used to create sculpture and relief. Identifying carving requires understanding the original dimensions of the material, as the highest surfaces of a carving will represent areas where the least amount of material was removed. In Figure 27A, there is clear use of negative space between two raised areas. This indicates that the craftsperson used extractive techniques to shape this region.

6.1.1 Quantification and Recording Techniques

Researchers need to consider how the choice of quantification strategy will affect the interpretation of the archaeological assemblage. Adopting a quantification strategy akin to the number of identified specimens (NISP) metric in zooarchaeology (i.e., each fragment is counted as a single unit) may be appropriate for certain assemblages. However, a metric like NISP can be disadvantageous when the assemblage is highly fragmented. As in zooarchaeology, counting each fragment has the ability to overrepresent the quantity of materials that were initially deposited. It is important for the researcher to decide on a procedure for studying horn core, as this material can be very common within the faunal assemblage, prone to fragmentation, and its presence in the archaeological record is not always the result of a craft production action. Within an archaeological assemblage, horn core might be both ubiquitous and predisposed to poor preservation, meaning that a researcher could end up quantifying several fragments originating from the same element. Moreover, most of the horn core is not likely to show evidence of anthropogenic modification (i.e., the horn core exhibits a transverse cut at the base and the rest of the element is unmodified). In this case, the researcher can choose to quantify only pieces of horn core showing evidence of modification. Such an approach might not be appropriate for other materials, such as elephant ivory. If the researcher is studying an assemblage in which elephant ivory is a product of long-distance trade, every fragment should be counted regardless of size or signs of modification. Researchers need to choose a quantification strategy that suits the assemblage they are studying. A good strategy will attempt to treat each worked animal object as a single unit, each with accompanying measurements and observations. Additionally, the risk of over-representing certain materials or objects can be countered by weighing each unit of observation.

Excavation projects assign identifying information to archaeological finds in several ways, for example certain objects may receive a “small finds” number, while others are collected in bulk. To study an assemblage of worked animal objects properly, each unit of observation needs to have a unique identifier. Therefore, it is often necessary for the researcher to maintain an independent system of recording, assigning ID numbers to both finished objects and scraps of production waste. Assemblages of worked animal materials can be large and varied, requiring a recording strategy that can keep track of quantitative (e.g., measurements) and qualitative data (e.g., descriptions). A database has many advantages for such research, as the data can be standardized, queried, easily shared, and exported into other file formats. Additionally, database software can associate and display images alongside the data, which aids in interpreting and classifying the assemblage. A simple relational database for recording information about worked animal objects might consist of three tables: Worked Objects, Modifications, and Measurements. Each object would have a single unique ID (“Main ID”) on the Worked Objects table. This table would also have fields to record the taxon, the material type, observations about material type, a description, the archaeological context, and a count (usually equal to 1). Recording the measurements and observations of modifications requires separate tables, as there are multiple observations (e.g., different types of measurements) associated with a single object. The Modifications and Measurements tables will both have unique IDs (Modification ID and Measurement ID) for each observation. In place of database software, a similar recording strategy can also be achieved with multiple spreadsheets (for examples of a relational database and spreadsheets, see supplementary files).

6.1.2 Photography

Depending on the time frame of the study and the size of the assemblage, researchers should aim to record several images of each object. In the context of archaeological sites and museums, traditional object photography tries to reflect accurately the color, scale, and shape of an object. Such photographs are appropriate for more general publications and catalogs, but this style of photography may be less effective for studying and documenting worked animal objects. So, in addition to more traditional photography, researchers should also take photographs that help explain the relationship between the orientation of the original animal material and the archaeological object. A top view of an object that captures the entirety of the cross section of a long bone shaft provides clear insight into how the object was created. Diagnostic features like the Schreger pattern of proboscidean ivory or secondary dentine of walrus ivory are also useful for conveying information about the species and the material, all of which will be useful to other researchers.

Researchers should also take photographs that highlight signs of modification. Documentation of cut marks, drill holes, and evidence of abrasion is useful for articulating the steps of the production process. However, the lighting used in traditional object photography may be insufficient for capturing these marks. The use of intense raking light can produce high-contrast images, which make tool marks and other modifications stand out (see Figure 28). Keeping the object in one position and taking a series of photographs with the light source at different orientations provides a way of documenting a range of modifications, and annotating these images can complement the written descriptions as well.

6.1.3 Measurements

Measurements for worked animal objects can be variable and dependent on the type of object. As the difference between “height” and “length” depends on how the object is oriented, measurements could easily differ between researchers. Unlike other types of archaeological objects that are more standardized, there is rarely a consensus about the types of measurements needed to study worked animal objects. As a result, it is important to be thorough and descriptive about how the measurements were taken. When recording a measurement, the researcher should accompany it with a description that would allow other researchers to understand the precise meaning of that measurement. Figure 29 shows a fragmentary ivory object with several measurements that aim to account accurately for the shape of the object. Descriptions of those measurements are as follows: the preserved length of the object, from finished end to broken end (A); the width of object at the finished end/width of object at the widest point (B); the diameter of drill hole nearest to the finished end (C), and the width of object at the broken point/width of object at the narrowest point (D). In addition, researchers should also measure the thickness of the object.

Figure 29 Ivory needle from northern Upper Egypt (ca. 4400–3800 BCE) showing types of measurements: The preserved length of the object, from finished end to broken end (A); the width of object at the finished end/width of object at the widest point (B); the diameter of drill hole nearest to the finished end (C), and the width of object at the broken point/width of object at the narrowest point (D).

Source: Metropolitan Museum of Art, accession number: 32.2.39.

6.1.4 Taxonomy and Material Type

The biological aspects of worked animal objects, those traits normally studied by zooarchaeologists, are crucial for understanding how these objects were created and used in the past. Researchers unfamiliar with the study of animal bones should attempt to work with a zooarchaeologist, although such collaborations are not always possible. Without being able to consult with a specialist, researchers should attempt to record taxonomic information in a way that is responsible and transparent. Most worked bone objects are made from mammalian skeletal material, which is often distinguishable from that of birds, reptiles, and fish. However, many worked animal objects are the result of a significant alteration of the original material, often precluding a species-level identification. Unless absolutely certain of the origin of the material, researchers should opt for larger, more general taxonomic categories. For example, an object made from a metapodial may be identifiable as originating from an equid rather than a ruminant, but differentiating between donkey (Equus asinus) and horse (Equus caballus) can be challenging. Therefore, researchers should record that the object belonged to category like “equid” or “horse, onager, or donkey.”

Even if it is not feasible to identify the species or make a more general taxonomic classification (e.g., order, family, and genus), it may still be possible to determine that an object came from an animal of a certain size, e.g., “large mammal” (e.g., red deer, cow, bear, or horse), “medium mammal” (e.g., sheep, goat, and pig), or “small mammal” (e.g., rodent, cat). If this approach is taken, it is incumbent on researchers to define clearly what constitutes “large,” “medium,” or “small.” When nothing can be said about taxonomy, researchers should specify that the animal material is from an “indeterminate vertebrate.”

Researchers should also attempt their best approximation of the material type. As material identification can be challenging, it is best to record the object with a more flexible description: “bone or elephant ivory,” “bone or antler,” “ivory (hippopotamus or elephant),” “ivory (non-elephant).” The challenges of differentiating types of materials make it more responsible and helpful for other researchers to describe an object with a flexible description, such as “bone or ivory.” While this ambiguity may seem inexpert, it indicates to other researchers that the identifications are more likely to be accurate (if imprecise). More descriptive classifications can be disadvantageous for quantifying data, so researchers may also choose to record a more standardized set of terms for the purposes of creating charts and graphs (e.g., bone, ivory, antler, unknown). More ambiguous classifications (e.g., “bone or elephant ivory,” “bone or antler”) would fall under the “unknown” category for the purposes of quantification. In the case of objects made from bone, it is also beneficial to record information about the skeletal element. Significantly carved bone objects can be impossible to identify, so researchers should opt for the best possible approximation of the element, e.g., “unknown,” “long bone or metapodial,” “phalanx 1 or 2.” Classifications should be accompanied by notes on the characteristics or metrics used in the decision-making process.

• The object exhibits the unmodified distal end of a ruminant metapodial. Based on the size and morphology, it likely originates from a sheep, goat, or fallow deer.

• The object is made from proboscidean ivory based on the appearance of the Schreger pattern visible on one of the cut surfaces.

• The material seems to be bone or antler, as it exhibits both cortical and trabecular skeletal tissue.

• The material is unknown, although likely some type of tooth because it shows no diagnostic signs of bone (e.g., Haversian canals, trabecular tissue).

• The object was carved from the diaphysis (shaft) of a long bone.

6.1.5 Taphonomy

Skeletal materials are prone to multiple forms of deterioration and degradation in the burial environment, so recognizing the effects of taphonomic processes on animal materials is another important aspect of the recording process. The study of such taphonomic processes is an entire subfield of zooarchaeology (see Lyman Reference Lyman1994; Fernández-Jalvo & Andrews Reference Fernández-Jalvo and Andrews2016), so researchers may be unfamiliar with the range of different alterations to skeletal materials. Moreover, there are taphonomic processes which mimic effects of production and use (e.g., abrasion), so researchers should take note of the surface or condition of the animal material which may not be the result of anthropogenic actions. A variety of other taphonomic factors may affect the appearance of worked animal objects. Such objects may have small, irregular marks caused by the gnawing of rodents or the growth of plant roots. There are also factors that can discolor animal materials, including metal staining, chemicals in the deposit, or fungal growth. Additionally, exposure to sunlight or moisture can negatively impact the surfaces of worked animal materials. Unfamiliarity with faunal materials may make identifying specific signatures of taphonomic processes difficult, so researchers should write a general description of the condition and color of the worked animal object.