Many species exhibit skewed sex ratios at birth. Here we investigate the relationships between environmental and maternal variables (as surrogates for maternal condition) and foetal sex in African buffalo Syncerus caffer and elephant Loxodonta africana of the Kruger National Park, South Africa. Using logistic regression no significant effect was found of year, maternal lactational status, maternal age, rainfall or density on foetal sex ratio. Using a subset of our data, it was also concluded that maternal body condition did not affect foetal sex ratio in buffalo. Our analyses failed to support hypotheses predicting that mothers will skew the sex ratios of their offspring in relation to their body condition. In this study, buffalo and elephant produced offspring with a sex ratio close to parity. Our results are discussed in light of the implications for testing such hypotheses in analyses of population level.

A distinctive new striped bandicoot of the genus Microperoryctes (M. aplini new species) is described and compared with Microperoryctes murina, another little-known bandicoot with which the new species has been confused in the past. The smallest of all living bandicoots, M. aplini is apparently restricted to high-elevation forests in the Arfak Mountains of the Vogelkop Peninsula of western New Guinea. The similarly small M. murina is known only from high-elevation forests on Gunung Sumuri, a peak in the Weyland Range of western New Guinea. The two species differ markedly in fur colour and ornamentation, pelage texture, external proportions, and quantitative and qualitative craniodental aspects, and may not be immediately related to one another.

The spatial organization of one clan of spotted hyenas Crocuta crocuta in the centre of the Etosha National Park, Namibia, is described during the dry and the wet seasons. The clan comprised 11 adults and sub-adults and occupied a territory of 160 km2 in the dry season and 320 km2 in the wet season. The dry season territory contained a low density (one animal/km2) of resident herbivores, such as gemsbok Oryx gazella, kudu Tragelaphus strepsiceros, giraffe Giraffa camelopardis, steenbok Raphicerus campestris and ostrich Struthio camelus, and a higher density of migratory species (12 animals/km2), principally springbok Antidorcas marsupialis, zebra Equus burchelli and wildebeest Connochaetes taurinus. These migratory species were the main prey of clan members. At the start of the wet season, the migratory herbivores migrated to the north-west, resulting in a considerable decline in the density of prey in the area used by clan members during the dry season. In response to this decline in prey, clan members followed the migratory herds and shifted the focus of their activities to an area grazed by migratory herbivores during the wet season. There existed a strong spatial relationship between the hyena density and the migratory prey density in both the dry and wet season. We postulate that the considerable enlargement of the clan territory in the wet season is a response to both the migratory movements of prey and an increase in the dispersion of prey during the wet season.

Variation in size-assortative pairing was studied in relation to sexual selection on male body size in the amphipod Gammarus pulex, using both transverse and longitudinal surveys of natural populations. In addition, the influence of male–male competition on size-assortative pairing was tested in the laboratory. In both surveys, the intensity of sexual selection was positive and significant for male body size but not for females, and size-assortative pairing was positive and significant. The magnitude of size-assortative pairing, however, varied significantly between populations. The magnitude of size-assortative pairing was positively correlated with the intensity of sexual selection on male body size in both surveys. In the laboratory, the strength of size-assortative pairing decreased with decreasing male:female ratio. Taken together our results point to a role of interference competition between males in promoting patterns of size-assortative pairing in G. pulex, although alternative explanations (i.e. female resistance) cannot be excluded.

Circulating testosterone levels were measured at 195, 318 and 437 days of age in 76 male garter snakes (Thamnophis sirtalis) born to 26 wild-caught females. Testosterone levels increased significantly with increasing mass at all three ages and differed significantly among families at 318 and 437 days. ‘Full-sib’ estimates of heritability were near one at 318 and 437 days but these estimates may be inflated by maternal effects, dominance and epistasis. Evidence of heritable variation in circulating testosterone levels suggests that the evolution of traits affected by this hormone (reproductive, territorial and agonistic behaviour; body size and shape) might be mediated through changes in this hormonal control mechanism.

The main objective of this project was to provide baseline data on faecal parasites of groups of non-human primates from Tambopata Research Center, Tambopata National Reserve, Peru. All primate species found in this area were sampled: red howler monkeys Alouatta seniculus, night monkeys Aotus vociferans, spider monkeys Ateles bezlebuth chamek, brown titi monkeys Callicebus brunneus, white-fronted capuchins Cebus albifrons, brown capuchins Cebus apella, saddleback tamarins Saguinus fuscicollis and squirrel monkeys Saimiri sciureus. Individuals from four howler monkey troops, three brown titi monkey troops, two squirrel monkey troops and one troop each of night monkeys, spider monkeys, brown capuchins, white-fronted capuchins and saddleback tamarins were sampled. Faecal samples were collected from July to October 2002 from 86 individuals. A concentration test was used to analyse faecal samples. Results indicate the presence of various protozoans, Ancyclostoma sp., Ascaris sp., Strongyloides stercoralis, Trichuris trichiura, Prosthenorchis elegans and Schistosoma mansoni.

The reproductive system is described from 15 giant squid Architeuthis sp., collected between 1972 and 2002 in South African waters. Distinctive features of the male reproductive system are the long muscular terminal organ, with elaboration of the anterior end, and modification of the tips of the ventral arms, probably hectocotilization. The spermatophoric organ has a long finishing gland that extends from the base of the gill. The terminal organ is differentiated internally into three distinct parts, involved in the guidance, storage, protection, expulsion and possibly the coating of spermatophores. Length of spermatophores in the terminal organ varied considerably. Several stages of spermatophores were found, from tentative to false to fully formed spermatophores, within a single animal. Distinctive features of the female reproductive system are a mesentery surrounding the main blood vessels of the ovary and attaching the ovary to the dorsal gladius chamber, multiple branching (at least three times) of the genital aorta that supplies the developing oocytes, high potential fecundity (3.5–6.2×106 oocytes), small eggs and short oviducts that suggest intermittent (extended) spawning. Large concentrations and single spermatangia were found in various places in females, indicating non-specific deposition. The transfer of spermatophores is probably rapid, perhaps because of considerable sexual size dimorphism (at maturity, males are much smaller than females). Implants in males are probably self-induced since the majority were found within reach of the terminal organ opening (primarily on the ventral arms in males).

Separation of low digestible fibres and fermentation of the digestible part of the food in the caecum is an adaptation of some small herbivores to cope with low-quality forage. The caecum content is later re-ingested as soft faeces so that the herbivore can benefit from this protein-rich material. This is known as caecotrophy and is a common phenomenon in species of leporids, although differences exist between hares and rabbits. Hares have amorphous soft faeces and the amount of soft faeces produced is smaller compared to that of rabbits. Both factors suggest that hares have smaller benefits from re-ingestion of the caecal contents compared with rabbits and, as a consequence, have a less efficient digestion (mainly of nitrogen) compared to rabbits. The assertion was tested whether digestive efficiency is different between the two herbivores and how this affects the choice of food plants in a natural situation. A feeding trial was conducted using hares and rabbits fed with diets with a range of fibre contents. Dry matter digestibility was not different, but nitrogen digestibility was lower in hares than in rabbits, indicating a less efficient digestion of protein. Both taxa showed a different response to increased fibre content in the diet. Rabbits maximized digestibility by increasing retention time of the food, hares maximized digestion rate by increasing the passage rate of the food through the digestive tract. The daily digestible nitrogen intake was higher in hares Lepus europaeus than that in rabbits Oryctolagus cuniculus, indicating that hares compensated for their lower nitrogen digestibility. Hares were predicted to select for higher quality plant species in a natural situation, but they had, on average, a lower nitrogen and higher total fibre content in their diet compared to sympatrically occurring rabbits. This indicated that hares did not compensate for their lower digestive efficiency by selecting higher quality food plants. The present experiment shows that hares and rabbits have different digestive strategies to cope with low quality forage. Rabbits had a higher N-digestibility by increasing the retention time, whereas hares appeared to compensate for their lower N-digestibility by increasing the processing rate, when food quality deteriorated.

The behavioural response of the sleepy lizard Tiliqua rugosa to an extended drought was examined in spring and summer 2002. Observations of the behaviour and use of microhabitat by radio-tagged lizards for spring in 2000–2002 showed that the lizards in 2002 suffered decreased body mass and increased mortality, were less active, showed reduced mating behaviour and increased use of burrows when compared with the more normal wetter years of 2000 and 2001. The lizards lost significant mass owing to dehydration and starvation. An ‘onboard’ data logger recorded lizard stride frequency and body temperature continuously for 4 months on 11 lizards during the drought of 2002. The normally diurnal heliothermic sleepy lizards responded to rare rainfall events during the drought whenever they occurred, day or night, by emerging from burrows or other shelters for extended periods of activity with sub-optimal body temperatures as low as 8.5 °C. They moved more often, and with higher stride frequencies during periods of rain than during dry periods, both overnight and during the day. As a consequence of this extended activity under physiological stress, the lizards were able to respond to naturally occurring transient opportunities for food and water that would not have been available if they were only active at optimal body temperatures. In an area where freestanding water is rarely available, the lizards were able to access limited water by licking substrate. They also gained water and perhaps nutrition by consuming the temporarily rehydrated thalli of the free-living terrestrial cyanobacterium Nostoc commune. Such behaviour enabled lizards to regain much of the mass lost before the rainfall and probably enabled many lizards to survive until more normal food sources became available. These rare events may have a significant effect on the shaping of the sleepy lizards phenotypic capacities outside routine day-to-day activities.

If the energy-density of prey bodies is not uniform, predators usually should maximize their rate of energy intake while foraging by selectively consuming energy-rich regions of their prey and discarding other parts. In this study, the hypothesis of selective body-part consumption was tested using two species of dasyurid marsupials, Sminthopsis youngsoni and Ningaui ridei, and their invertebrate prey in arid central Australia. Energy-densities were similar for several divergent types of prey, including whole insects, centipedes, and spiders (20.2±2.19 (sd) J/mg ash-free dry mass), but there were marked differences in energy-density among orders of insects and also between different body regions of invertebrates. In captivity, the two dasyurid species consumed different body regions of prey in the same way. For beetles and cockroaches, the rank order for selection of body parts was abdomen, thorax, head, then legs; for centipedes it was body, then head + legs; and for spiders it was opisthosoma, prosoma and then legs. Selection of prey body regions by the marsupials correlated closely with the energy-densities of these regions, and also with the rates of energy intake that they yielded. In the field, selection of body parts of arthropod prey by dasyurids probably occurs primarily when prey is abundant. This selection should allow maximization of rates of energy intake in favourable periods and should, in turn, allow dasyurid predators to effectively exploit pulses of prey resources in the temporally variable desert environment.

Linear enamel hypoplasia (LEH), a deficiency in enamel formation visible on mammal tooth crowns, can be used as a retrospective indicator of physiological stress and developmental health in humans and animals. In this first study, for north-western Europe, the condition has been recorded from prehistoric (mesolithic) and recent populations of wild boar, and from domestic pigs belonging to early farming (neolithic) communities. It was possible to show that LEH occurs in recent and ancient populations of wild boar from north-west Europe, and that the occurrence of the condition can be explained by the same events within the animal's life (birth, weaning, winter starvation) as has been previously suggested for archaeological domestic pig samples. The frequency of LEH is consistently low within all ancient and recent populations of wild boar studied, a remarkable observation given the pronounced differences in the living conditions of these two diachronically well-separated groups, mainly linked with the increasing human pressure on recent populations of wild animals. Early domestic samples generally show high LEH frequencies, although considerable variation exists between the samples. It is suggested that these high frequencies are, in general, the result of domestication, while the variation could be related to differences in early husbandry. The observation of LEH, therefore, provides a valuable tool for studying the history of animal domestication.

In ungulates, males and females have contrasting life histories, as usually only the females raise the young. How reproductive effort in males varies with individual level and population level characteristics has received little attention in the literature. Using published information on direct (weight loss during the rut) and indirect (rut-related changes in activity budgets, fighting frequency, etc.) measures of reproductive effort, we tested whether effort in males increased with (H1) increasing age, (H2) increasing body size, (H3) decreasing population density, (H4) increasingly female-biased sex ratio and with a younger male age structure. Consistent with H1, reproductive effort was consistently higher in prime-aged than in younger males in a large number of studies. Among younger males, sub-adult males had an equal or higher effort than yearling males. Prime-aged males had more typical rutting behaviour (e.g. roaring, tending, fighting and chasing frequencies) and they often lowered their intake of forage during the rut. However, reproductive effort usually declined for very old age classes. Reproductive effort increased with size (H2) also after accounting for age. Data on effort vs (H3) density and (H4) sex ratio/male age structure were inconclusive. Clearly, far more studies relating effort to population characteristics are needed before the rutting ecology of male ungulates can be understood.