Onychophora lead a cryptic lifestyle as predators in decaying logs and leaf litter. Hence, very little is known about their behaviour. They are generally assumed to possess only a limited behavioural repertoire, even though their surprisingly evolved brain suggests otherwise. Our studies on the Australian species Euperipatoides rowelli show for the first time that onychophorans are indeed capable of complex behaviour. Euperipatoides rowelli individuals form aggregations of up to 15 females, males and young. These aggregations are not random assemblages, but close social groups organized in a hierarchy based on female dominance. Food is hunted collectively, but the dominant female of a group feeds alone, before other females, males and young. Hierarchy within a group is established by aggressive-dominant and passive-subordinate behaviours, the latter leading to tolerance of body contact and aggregation. Euperipatoides rowelli from foreign groups, i.e. from different logs, are met with intense aggression, and individuals rarely aggregate. The reasons for this aggression are not clear, but we suggest that its origins lie in kin recognition. The evolution of social behaviour within the Onychophora is discussed with respect to their ecology, population genetics and phylogeny.

An objective multivariate technique is described for identification of individual tigers Panthera tigris from their pugmarks. Tracings and photographs of hind pugmarks were obtained from 23 pugmark-sets of 19 individually known tigers (17 wild and two captive tigers). These 23 pugmark-sets were then divided into two groups, one of 15 pugmark-sets for model building and another of eight pugmark-sets for model testing and validation. A total of 93 measurements were taken from each pugmark along with three gait measurements. We used CV ratio, F-ratio and removed highly correlated variables to finally select 11 variables from these 93 variables. These 11 variables did not differ between left and right pugmarks. Stepwise discriminant function analysis (DFA) based on these 11 variables correctly classified pugmark-sets to individual tigers. A realistic population estimation exercise was simulated using the validation dataset. The algorithms developed here correctly allocated each pugmark-set to the correct individual tiger. The effect of extraneous factors, i.e. soil depth and multiple tracers, was also tested and pugmark tracings compared with pugmark photographs. We recommend collecting pugmarks from soil depths ranging between 0.5 and 1.0 cm, and advocate the use of pugmark photographs rather than pugmark tracings to eliminate the chance of obtaining substandard data from untrained tracers. Our study suggests that tigers can be individually identified from their pugmarks with a high level of accuracy and pugmark-sets could be used for population estimation of tigers within a statistically designed mark–recapture framework.

Ontogeny and sexual dimorphism have been important topics of investigation among researchers interested in the life history and ecology of non-human primates. It has been suggested that sex differences in the duration of growth are primarily, but not entirely, responsible for the sexual dimorphism observed in primate species with multimale–multifemale social structure, such as that seen in macaque monkeys (subfamily Cercopithecinae). Sexual dimorphism and growth was investigated in a wild population of booted macaques Macaca ochreata from Sulawesi, Indonesia. The results of our investigation suggest that the observed dimorphism in this population is primarily a product of greatly increased growth rates in dentally mature young adult males, in addition to prolonged male growth. This pattern of male growth may be an adaptive response to reduce the risk of adult male aggression before obligatory male emigration, and to facilitate competition for females soon after immigration into a new social group.

Predation between invading and native species can produce patterns of exclusion and coexistence. Dikerogammarus villosus, a Ponto-Caspian amphipod species, has invaded many central European freshwaters in the past decade, replacing native Gammarus amphipod species. For instance, the arrival of D. villosus in Holland has been accompanied by the decline of Gammarus duebeni and G. tigrinus populations within invaded systems. This study examined what may happen when D. villosus eventually encounters native Dutch populations of Gammarus pulex, and how factors such as microhabitat and food resource availability could contribute to a future species replacement or coexistence. A laboratory simulation of a lake/pooled area of river indicated that G. pulex and D. villosus differed in distribution within the same habitat, and showed that although the distribution of the native differed in the presence of the invader, the presence of the native had no effect on the distribution of the invader. Gammarus pulex suffered severe intraguild predation (IGP) from D. villosus in mixed species treatments with no reciprocal predation of D. villosus by G. pulex. This IGP occurred regardless of whether no alternative food resource was available (91% of the G. pulex population eliminated after 7 days), or alternative foods/prey were available to excess, such as leaf material (85%), chironomids (77%) or fish food flakes (74%). We conclude that although differential microdistribution of the two species could promote coexistence, the presence of alternative foods/prey resources, merely slow the rate of IGP and replacement of the native by the invader. Our study joins one of an increasing number emphasizing the potential damaging impacts of D. villosus on native communities.

Acanthocephala are parasites with complex life cycles involving arthropod intermediate hosts and vertebrate final hosts. They use predation as a means of transmission, and some species have developed the ability to modify behaviour of their intermediate hosts to enhance the probability of ingestion by the definitive host. Knowledge of how a single parasite species is adapted to modify the behaviour of different intermediate host species is important for the understanding of parasitic transmission in host communities. In Burgundy, the freshwater amphipod crustaceans Gammarus pulex (native species) and Gammarus roeseli (eastern European invader) are both intermediate hosts for the acanthocephalan Polymorphus minutus. The influence of this bird parasite on the geotaxis of G. roeseli was evaluated and it was found that when infected, individuals of this host species have a negative geotaxis compared to uninfected individuals. There were two components to the behavioural changes: swimming to the top of the water column, and clinging to surface material. These changes were comparable to those observed in the local host species G. pulex, but lower in magnitude. This result contrasts with a previous study on the influence of the fish parasite Pomphorhynchus laevis, which is able to alter the native species' behaviour, but not that of the invasive host. Parasite adaptations to local vs invasive intermediate host species are discussed in terms of their dispersal range (i.e. dispersal of their definitive hosts): the wider the dispersal, the greater should be the spectrum of intermediate hosts.

Caecilians are an order of amphibians with distribution confined to several of the tropical countries. They are subterranean animals and practice a form of internal fertilization. Several species are viviparous. Published reports on seasonal variation in male reproduction in caecilians are limited to a very few species. A study was undertaken to examine the seasonal variation of testicular activity with respect to spermatogenesis and steroidogenesis in a caecilian, Ichthyophis tricolor, fairly abundant in the Western Ghats of Kerala, India, using light and transmission electron microscopy, terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL) staining and biochemical determination of 3-hydroxy-Δ5-steroid dehydrogenase (Δ5-3β-HSDH) activity. Three phases in spermatogenic activity, active spermatogenesis (July–November), early regression (December–March) and spermatogenic quiescence (April–June) are identified. Apoptosis seems to be the mechanism of germ cell death during the regression phase. Leydig cells are interstitial and not peritubular. Activity of testicular Δ5-3β-HSDH follows the same pattern as spermatogenic activity, although histometric data on the interstitial tissue reveal higher areas during the regression and quiescent phases. Our findings will be useful in evolving strategies for conservation of caecilians with special reference to Kerala, India.

Osteophagia, variable serum calcium (Ca) and phosphorus (P) concentration, high serum alkaline phosphatase activity, a high growth rate, and a large skeletal mass, all suggest that Ca and P requirements and availability are finely balanced in giraffes. The mineral content of some marker bones in skeletons obtained from adult male giraffes (browsers) and adult male African buffaloes (grazers of similar body mass) were compared to assess the idea of critical Ca and P balance. Our results show that the P concentration of plasma varies more than Ca concentration, and that the Ca content of giraffe bones (0.196±0.01 g/g) and buffalo (0.202±0.006 g/g) varies more than P content (0.095±0.002 in both). The average Ca and P content of the bones analysed was similar in both species (Ca=∼20.0%, P=∼9.5%). Giraffe skeletons, however, contain three times more Ca and P than do buffalo skeletons. This translates into a 1.5–2.0 fold higher Ca requirement for giraffes, with which they seem to cope effectively by selection for Ca-rich, dicotyledonous, browse. Sources of P to meet requirements are not obvious and a seasonal deficiency of P is a more likely cause of observed osteophagia than Ca deficiency. Giraffe rib P density, the best measure of P balance, of 0.142±0.01 g/cm3 is, however, above the deficiency threshold. Bone mineral content (Ca and P) correlates well with bone density and shows only slight differences between adult males of the two species.

This work presents new data from 48 maned sloths Bradypus torquatus captured between November 2002 and November 2003 in three regions of the Atlantic forest where the largest remnant populations of this species are found. Data from another long-term study, carried out from 1994 to 1996 and from 1999 to the present (n=14), were also used, making a total sample of 62 sloths. Average adult body weight is 6594±236 g and average head-body length is 66.5±0.8 cm (n=35), indicating that Bradypus torquatus is the heaviest of all four Bradypus species. Individuals from lower-montane forests (600–1000 m a.s.l.) are significantly larger (head–body length; t-test; P=0.001) than individuals from the lowlands (<350 m a.s.l.), suggesting altitudinal differentiation between populations. Sexual dimorphism, here reported for the first time, was found in body length (females are significantly larger than males) and in other external characters, such as mane size and form (darker and larger in males), and size and shape of the external genitalia. Most differences between sexes are, however, only discernible in reproductively active individuals. Breeding is slightly seasonal; minimum observed interbirth interval was 1 year and litter size was always one. Infants stayed with their mothers until 8–11 months old; started feeding on solid food as early as 2 weeks old but continued suckling until c. 4 months of age. Age of sexual maturity was estimated at 2–3 years and the oldest captured maned sloth was a healthy male who was at least 12 years of age. Overall, results indicated that maned sloths are similar in these aspects to congeneric species. Information presented here significantly improves the current knowledge on this endangered sloth species and is useful for the proper planning and implementation of in situ conservation strategies such as translocations and reintroductions.

The Cape mole-rat Georychus capensis is a solitary subterranean rodent that exhibits seasonal reproduction. This study set out to determine whether the female Cape mole-rat is an induced or spontaneous ovulator. Eleven females were collected from the field just before the breeding season and housed individually. Urine was collected for 5 weeks. Females were subjected to one of three trials: housed separately without a male; allowed only non-physical contact with unvasectomized males; placed in direct contact with four vasectomized males. Urine was collected for a further 5 weeks and urinary progesterone profiles established. Females housed in direct contact with males exhibited heightened progesterone concentrations and the presence of corpora lutea in their ovaries. The act of coitus seems to be necessary for ovulation to occur in the females even though males were not capable of fertilization.

This study focuses on possible sources of egg size variation in the northern lapwing Vanellus vanellus, a polygynous shorebird with more variable male than female reproductive success. From the hypothesis that female birds allocate more resources into male than female eggs to improve their sons' abilities to compete for mates, male eggs were predicted to be larger than female eggs, and the proportion of sons was predicted to increase with mean egg volume of clutches. However, no size differences between male and female eggs were found. Corresponding with earlier reports in the species, egg size was positively correlated with female body condition, but no relationship between offspring sex ratios and intra-clutch mean egg volumes was detected. These results suggest that a higher variation in reproductive success among males than among females is not sufficient for sexually dimorphic eggs to evolve in birds. Moreover, previous studies have suggested that shorebird eggs are subject to stabilizing selection for equal size within clutches. In contrast, this study demonstrates a consistent variation in egg size, with a significant increase in egg breadth between first and second eggs, and decreases in both breadth and volume between the third and the final fourth egg. The volume of last-laid eggs was on average 2.3% smaller than the mean size of the preceding three eggs. Among the shorebirds studied so far, this consistent pattern of intra-clutch egg size variation is unique to lapwings.

During the last two decades, populations of the wild boar Sus scrofa in Europe have increased considerably and the species has spread into new areas over the entire continent. Because of the animals' impact on agriculture, livestock and biodiversity, and the resulting necessity of realistic management practices, we were interested in the key environmental factors responsible for this remarkable development. The study was based on data from the canton Thurgau, a region in north-eastern Switzerland. We used data on damage and hunting success to calculate a population density index and related it to eight variables describing ecological conditions, demography and hunting pressure (measured by the number of hunters) over a 25-year period. The analysis shows that the population increase correlates with higher than average winter and spring temperatures and improved food supply through more mast years and an increase in the area of maize cultivation. While favourable temperature conditions mainly reduce juvenile mortality, enhanced food availability is likely to boost reproductive success through younger age at first reproduction, larger litter size and earlier onset of oestrus within a season. Given this link between food and reproduction, supplemental feeding, a management practice recommended and very common all over Europe, should be reconsidered.

In constructing large vegetated mounds, Macrotermes termites play a key functional role in many African savanna systems. This study focuses on ungulate feeding on Macrotermes termitaria vegetation in Lake Mburo National Park, Uganda. With the exception of oribi Ourebia ourebi, all the species studied (i.e. impala Aepyceros melampus, Burchell's zebra Equus burchelli, Defassa waterbuck Kobus ellipsiprymnus, topi Damaliscus lunatus, bushbuck Tragelaphus scriptus and warthog Phacochoerus africanus) grazed preferentially on mound areas compared to the adjacent savanna. Ruminant species grazed closer to termitaria than non-ruminants and female impala both browsed and grazed closer to mounds than males. No sexual difference in grazing distance to mounds was found for waterbuck.

In highly seasonal environments animals that use daily torpor usually do so during the rest phase. In subtropical and tropical environments, however, daily torpor may not necessarily be confined to the animals' rest phase. Animals may display torpor during the active phase. We investigated the daily rhythms and seasonal rhythms of body temperature (Tb) in normothermic and torpid free-ranging rock elephant shrews Elephantulus myurus at Weenen Game Reserve, KwaZulu-Natal, South Africa. Tbs were recorded using miniature dataloggers from May 2001 to May 2002. Daily patterns of Tb in normothermic E. myurus suggested polyphasic Tb patterns that nevertheless suggested a rest phase that was coincident with the daytime. When the elephant shrews used torpor, the lowest Tbs were observed during the night-time, such that torpor was used during the coldest part of the night and arousal was associated with the 3-h period around sunrise. We suggest that the principal benefit of a flexible daily rhythm of Tb was that it facilitated arousal by passive exogenous heating using ambient temperature cycles.