Morphological differences between two semi-arboreal, bird-eating island pitvipers, Bothrops insularis and Gloydius shedaoensis, and their mainland relatives were investigated. Mitochondrial DNA sequence data for two genes show B. insularis to be rooted within B. jararaca. Bothrops insularis has a more anterior heart, a relatively longer tail, a longer head, and shorter fangs than B. jararaca. The greater head length is paralleled in the ecologically similar G. shedaoensis. Increased head size may represent an adaptation to the abundance of larger food items (migratory passerine birds), providing a selective advantage to snakes able to switch to larger prey at an earlier age. Furthermore, B. insularis and G. shedaoensis have converged on similar body sizes from opposite ancestral states. Other characters, including fang length, tail length and size of neonates do not show parallel variation in G. shedaoensis and B. insularis, suggesting that caution is required when interpreting character state shifts coinciding with ecological shifts in a single species only.

The selection of summer forage by three sympatric ungulates in the Damodar Kunda region of upper Mustang in north Nepal was studied to assess the extent of food overlap between them. To compare their diets, a micro-histological technique of faecal analysis was used, adjusted for inherent biases by comparing it with bite-count data obtained in domestic goats. Tibetan argali Ovis ammon hodgsoni, naur (blue sheep or bharal) Pseudois nayaur and domestic goat Capra hircus consumed mostly forbs, graminoids and browse, respectively. The proportions of food items in their diets were significantly different both at the plant species (P<0.02) and at the forage category level (P<0.001). Except for sharing three common plants (Agrostis sp., Stipa sp. and Potentilla fruticosa), dietary overlap at the species level was quite low. At the forage category level, naur and domestic goat overlapped more than the other ungulate pairs. Although all three species were opportunistic, mixed feeders, argali was a more selective forb specialist grazer than the other two ungulates. Owing to some spatial separation and little dietary overlap, interspecific competition for summer forage was low. If animal densities increase, however, goats are expected to compete more with naur than with argali because of their more similar diets. Owing to differences in forage selection by argali and naur throughout their large geographical ranges, reflecting adaptations to local ecological conditions, inferences regarding forage competition between domestic livestock and these two wild caprins need to be made from local, site-specific studies, rather than from general diet comparisons.

Evidence suggests that behavioural defences, such as habitat selection and grooming behaviour, have evolved in animals in response to the costs associated with ectoparasites. Bat fly and mite densities were compared among wild-caught bats in Belize with different roosting preferences (cavity, foliage, or both), and grooming behaviour was analysed for bat species with high and low ectoparasite density. Ectoparasites of bats were removed using forceps, and bat grooming behaviour was recorded with a camcorder. Because bat flies pupate on the surface of host roosts, bats that use cavity roosts (a sheltered environment for the pupae) were predicted to have higher densities of bat flies than those that use foliage (exposed environment). Cavity-roosting species generally had higher densities of bat flies and mites, although the relationship was more evident for bat flies. The grooming behaviour of bats was predicted to differ among species with high or low ectoparasite densities. Although there was no difference in the frequency of grooming behaviours for individuals with and without bat flies, there were differences in grooming behaviour at the species level. Bat species with high ectoparasite densities scratched more than those with low ectoparasite densities. These results suggest that ectoparasite densities and grooming behaviour are related to roosting preferences in bats.

There is a considerable amount of literature on the diet and effect of feral American mink Mustela vison on the distribution and abundance of water voles Arvicola terrestris in Britain. Few recent studies, however, have attempted to examine the occurrence of water voles in the diets of native predators. Fox Vulpes vulpes scat and grey heron Ardea cinerea pellets were collected during winter 2003–2004 at a location known to contain a large number of water voles. These scats and pellets were subsequently analysed to determine the frequency of water vole occurrence in the diet of these opportunistic predators. Water vole remains were found in 30% of fox scats analysed and accounted for 13% of the total weight of scats. A total of 18% of heron pellets contained the fur of water voles in addition to the fur of four other rodent species. The potential role of native predators in the loss and fragmentation of site-specific populations of water voles in Britain is further discussed.

The Eastern Arc Mountains of eastern Africa are notable for the high levels of endemism exhibited by various forest-dwelling organisms of this ancient montane archipelago. There has been virtually no assessment of the variation among populations of small mammal species living on these unique mountains, but recent faunal surveys have produced sufficient material to initiate such studies. Cranial morphometric and DNA sequence data were examined from six populations of Sylvisorex howelli Jenkins, 1984, an endemic shrew found in several different massifs of the Eastern Arc Mountains, to assess variation across the archipelago in the context of various hypotheses of historical biogeography. Twenty-two cranial measurements were analysed using principal components analysis. Age classes (based on tooth wear) and sex had little effect on the variation exhibited by the variables studied. Overall, specimens of S. howelli from the East Usambara Mountains are smaller than specimens from other known populations. The mitochondrial ND2 and 12S rRNA genes from representatives of each montane population of S. howelli in addition to several crocidurine taxa from eastern Africa and three soricine outgroup species were sequenced to assess phylogenetic relationships among these taxa. Neither maximum likelihood, maximum parsimony, nor Bayesian analyses support monophyly of the genus Sylvisorex, but S. howelli populations were consistently recovered as a well-supported clade. Over 40 individuals of S. howelli from six disjunct montane ranges, comprising the entire known distribution of the species, were sequenced for 504 base pairs of ND2 to investigate phylogeographic patterns. Phylogenetic analysis recovered six reciprocally monophyletic haplotype clades grouped by locality. Branch lengths are consistent with relatively long periods of isolation among populations from the Uluguru, Ukaguru, Nguru, Nguu, East Usambara and West Usambara Mountains, with low levels of diversity observed within each population. These results are interpreted within the historical context of the Eastern Arc Mountains.

After their oceanic migration, juvenile European eels Anguilla anguilla enter estuaries as glass eels, develop into pigmented elvers and migrate into fresh water. Fisheries often transfer such eels abruptly between salinities, principally glass eels and elvers from estuarine to fresh water. It is usually assumed that survival rates are high, but this required systematic investigation. Survival was found to be 100% over 21 days of glass eels and semi-pigmented elvers transferred abruptly from estuary conditions into fresh water, 50% sea water and full sea water. Fully pigmented elvers, however, showed significantly reduced survival when transferred into sea water. Salinity preference experiments with juvenile eels have historically been inconclusive. Here, in a choice chamber design, a clear developmental shift in salinity preference was found, with glass eels preferring 100% sea water, semi-pigmented elvers showing no clear preference and fully pigmented elvers preferring fresh water. We conclude that eel fisheries enhancement by abrupt transfer of juveniles among salinities is largely vindicated. In addition, developmental shifts in salinity preference have been clarified and this aids in the interpretation of eel migration patterns.

In our study three badger Meles meles populations separated by only a few km but subjected to different environmental conditions were compared. Differences are especially marked for climatic factors, the three areas being located at different altitudes, and for intensivity of soil use by people. The diet of the three populations was significantly different, with one or two dominant items in each area: mammals and cereals in the mountain, maize in the mid-mountain and in the lowland areas. In the most intensively cultivated area, maize was the most consumed item in autumn and spring, several months after harvesting. Earthworms had only a secondary importance in the diet in the mountainous area, but were negligible in the mid-mountain and lowland areas. Soil management seemed to play a preponderant role, mostly owing to soil quality and topography. Climate seemed to have a secondary effect only.

Many studies have concluded that territoriality is absent in male bushbuck Tragelaphus scriptus but a minority has suggested that some exclusive mechanisms act between adult males. This study provides indirect evidence for the existence of territorial structures between adult male bushbuck by comparing home-range overlap between adult and sub-adult males. The spatial organization of individuals in relation to each other was established by using numerical classification. Location fixes of 52 males, each individual distinguished by a characteristic coat pattern, were taken over a period of 3 years. Home ranges were estimated using the fixed kernel density estimator. Two indices (coefficient of overlap, index of overlap) were applied to compare home-range overlap between the different male age classes. There was a strong home-range overlap up to the 30% home-range core between sub-adult as well as between adult and sub-adult males, while adult male home ranges overlapped up to the 50% home-range core only. It could be shown that home ranges of adult males overlapped significantly less than those of sub-adult males and those between sub-adult and adult males indicating an exclusive use of central core areas (home sites). Sub-adult males form bachelor pools without being permanently associated. With increasing age, sub-adult males challenge territory holders and replace them in order to take over their exclusive areas. These maturing sub-adult males (young adults), often focused on a particular territory holder denoting the young adults as prospects or candidates.

Feeding habits of smooth-coated otters Lutra perspicillata were studied by analysing spraints collected from around the Periyar Lake within the Periyar Tiger Reserve, Kerala, India. Remains were identified by the comparison of body parts with a reference collection of appropriate prey species. Two methods were used to estimate the proportions of different prey consumed: frequency of occurrence and score-bulk estimate. The number of prey types in a spraint varied between one and seven. More prey species were found during low water levels (March–April). Fish was the major prey, followed by frogs, crabs, birds and insects. Throughout the study, the exotic tilapia and European carp constituted the major prey in the diet. The quantity of native Deccan mahsheer and endemic Periyar barb in the diet was insignificant. A higher intake of bottom-dwelling catfish was observed during periods of low water, probably because of the increased efficiency of otters to forage at these levels. By consuming large amounts of exotic species, such as tilapia and European carp, otters might contribute to the control of the rapid expansion of these species in the Periyar Lake and adjacent water bodies in the reserve.

Recent data have shown that owing to their seed-predator capacity Chiroderma doriae and Chiroderma villosum trophically depart from all previously studied species within the canopy fruit-bat ensemble. In this paper, the hypothesis that morphological adaptations related to granivory have evolved in these bats is investigated and discussed. A canonical variate analysis was used to search for possible divergent trends between the masticatory apparatus of Chiroderma and other stenodermatines currently recognized in the same ensemble. A total of 142 specimens representative of eight species was included in the analysis. Species of Chiroderma can be discriminated from all other species in the sample based on the increased development of masseter-related variables (height of the anterior zygomatic arch, masseter moment arm, and masseter volume), which, in conjunction with other morphological characteristics (dentition and gape angle) discussed herein, corroborates the evolution of durophagy in this group. A complementary analysis based on a Mantel test revealed that the pattern of morphological differentiation that emerged from the canonical variate analysis does not agree with the one expected based solely on the phylogenetic relationships adopted for the canopy fruit-bats studied here. This result is consistent with the hypothesis that morphological adaptations related to granivory have evolved in Chiroderma.

Fundamental information on the ecology of the limbless tropical caecilians is needed for a well-founded conservation assessment. Here, essential life-history characters are presented for the oviparous caecilian Ichthyophis cf. kohtaoensis from a field site in South-east Asia (Mekong valley, north-eastern Thailand). Ichthyophis cf. kohtaoensis was found in a range of terrestrial macrohabitats including open scrubs, gallery forests and open secondary dipterocarp forests. In the dry season, caecilians were found mainly in soil but in the rainy season they were also detected in epigeic microhabitats (leaf litter or rotten vegetation). Ichthyophis cf. kohtaoensis were recorded in low densities (median 0.08 individuals/m2) and they share their habitat with a range of other terrestrial amphibians and reptiles. The population structure of I. cf. kohtaoensis varied seasonally. Records of late metamorphs were restricted to the cold dry season and occasionally to the onset of the rainy season. Females with clutches were only found in the rainy season. A life-history scenario of I. cf. kohtaoensis in north-eastern Thailand was set up. Reproduction and larval development is related to the rainy season. Mating and oviposition may start at the onset of the monsoon. Larvae hatch at the peak until the end of the rainy season and metamorphose until the end of the dry season. In the light of amphibian decline, this study may encourage further baseline work on the ecology of other caecilian species.

Skull variables were analysed for allometry patterns in 56 species of extant carnivores. As previously reported, many skull variables scale near isometrically with either skull length or lower jaw length. The maximal gape angle scales insignificantly (P<0.05) with skull size, but the clearance between the canines shows a significant relationship with skull size and scales near isometrically. Maximal bite forces were estimated from geometrical cross-sectional areas of dried skulls, and the bending strength of the canines was computed by modelling the canines as a cantilevered beam of solid, homogeneous material with an elliptical cross section. Previous hypotheses of large taxon differences in canine bending strengths, so that felids have stronger canines than canids, are corroborated when actual bite forces at the upper canine are ignored. Incorporation of bite force values, however, nullifies the differences in canine bending strength among felids and canids, and ursids seem to have stronger canines than felids. This is probably because of the significantly longer canines of felids compared to canids and ursids, and the generally high bite forces of felids.

Longer-term ecosystem level dynamics are often neglected in conservation studies involving single species. In this study, a retrospective analysis is presented on the feeding performance of African wild dogs Lycaon pictus in the Serengeti in relation to a competing species, the spotted hyena Crocuta crocuta, to test whether hyenas had an effect on feeding performance of wild dogs in this ecosystem. Our analysis is based on observations of over 700 wild dog kills recorded over a 20-year period (from 1964 to 1987) during which time there was a decline in wild dog numbers (ending with their local extinction in 1991) and a twofold increase in hyena density. Overall, the amount of time that dogs had access to the kill (access time) decreased with increasing numbers of hyenas attending kills, but access time increased with increasing hunting-group size of dogs and carcass mass. In addition, in the 1980s, dogs spent longer at kills than in the 1970s for a given set of conditions, including when hyenas were absent. Our analysis demonstrates a greater potential for group benefits than was found in a previous study (Carbone, Du Toit et al., 1997). Hunting-group sizes of between two and six dogs performed best when hyenas attended dog kills because the benefits of increased defence outweighed the costs of having to share the carcass with more dogs. Hunting-group sizes of wild dog and levels of hyena attendance at the kill broadly paralleled the population trends in these species, with hunting-group sizes of wild dog declining, followed by hyena attendance increasing. Despite the combined effects of increased hyena attendance and reduced hunting-group size, dogs in the 1980s typically spent longer feeding and consumed more of the carcass including the poorest sections. This suggests that dogs in the 1980s may have been under greater energetic stress.

To obtain data on home range, movements, activity and habitat use by giant anteaters Myrmecophaga tridactyla, seven animals were captured, radio-collared and monitored from March to December 2001 in a 104-km2 study area in the Pantanal wetland, Brazil. Four of five males used areas that covered 4.0–7.5 km2 (5.7±1.7 km2), and one of two females monitored occupied a larger area (11.9 km2) than the males, but none of the curves of cumulative area unequivocally reached the asymptote. Generally, there was considerable overlap among individual areas used. The home-range estimates were calculated using the 100% minimum convex polygon, and 95% adaptive kernel methods. The areas used by the giant anteaters in the Pantanal wetland were larger than home ranges of giant anteaters in the Serra da Canastra National Park, Brazil. The habitat types were generally used in the same order as they occurred in each home range. Two giant anteaters previously monitored with VHF radio-telemetry were subsequently tracked with a modified global positioning (GPS) system in different periods. The modified GPS acquired data on activity and habitat use for c. 9 days. Giant anteaters did not show a similar pattern of habitat use during the period of study using the modified GPS unit, but their activity patterns were similar. One of the ranges recorded over 9 days with this method was larger than the range obtained over 252 days by standard VHF radio-telemetry.

There are more taxa of wild pig in South-east Asia (SEA) than in any other comparable area in the world, but the number of species and subspecies is still uncertain. The taxonomy of some wild pig populations distributed in Malaysia, Indonesia and the Philippines, was investigated using molecular and morphometric techniques. Our results suggest the existence of two main evolutionary clades that are likely to have diverged during the Pliocene in SEA: one including wild pig populations distributed in the Philippines (Sus cebifrons) and Sulawesi (S. celebensis); the other including the Indonesian and Malaysian bearded pigs (S. barbatus), and the widespread Eurasian wild boar (S. scrofa). A possible scenario for pig speciation in SEA is developed, and the need for a taxonomic revision of bearded pigs suggested, particularly concerning the taxonomic status of S. b. ahoenobarbus from Palawan Island, and the existence a new species distributed in the Tawi Tawi Islands (Philippines). Unexpectedly, bearded pigs in the Malay Peninsula are closely related to the Bornean population, but distinct from Sumatran S. barbatus, and they should be considered as belonging to a different subspecies.

From May 1997 to July 1999, 24 gray foxes Urocyon cinereoargenteus were radio-marked and their fates monitored in a natural area of southern California to identify rates of survival and cause-specific mortality, and thus to assess population sustainability. Pup (0.4–1.0 years old) foxes had an 8-month (September–April) survival rate (0.34) that was lower than the 8-month (0.77) or 12-month (0.58) estimates for adult foxes. Interference competition was evident; 92% (11/12) of fox mortalities were the result of predation by sympatric coyotes Canis latrans or bobcats Felis rufus. Also, five of seven gray fox mortalities were outside of, or on the border of, the home range of the killed fox. Calculations indicated that the fox population would remain stable if survival of pups during their first 4 months of life was 0.68 (vs 0.75 for adults during these months and 0.58 for older pups for 4 other months). This seems reasonable, yet sympatric carnivores, mainly coyotes, clearly influence the gray fox population in southern California.

Age-related improvements in reproductive performance in seabirds have been well documented, and may be explained by improvements in foraging efficiency or increased experience and reproductive effort with age. The interactive effects of parental age and food supply on reproductive performance, however, remain poorly understood. A widespread mass mortality of pilchards Sardinops sagax in southern Australian waters in 1998 provided a unique opportunity to investigate the effects of a sudden reduction in the availability of amajor prey species on Australasian gannets Morus serrator, an important local marine predator. Age-related differences in the breeding performance of gannets were evident in 1 year of reduced pilchard availability; when food was not limited, both young and experienced parents were equally capable of rearing chicks and had similar levels of breeding success. These data clearly demonstrate the interactive effects of parental age and food supply on breeding performance and suggest that such differences only become apparent when conditions become more stressful.

The behaviour and survival of captive-born least weasels Mustela nivalis nivalis released in nature were reported in this study. Altogether 27 captive-born and six wild-caught weasels were equipped with radio transmitters and their survival was studied as a function of age and season. The daily mortality rate was generally higher in captive-born than in wild-caught weasels. The survival of captive-born weasels was highest if they were released during the summer and hence when they were young. Differences in the behavioural patterns of captive-born and wild-caught weasels were apparent. Captive-born weasels were often more visible in the field and were less timid than wild-caught weasels. Results suggest that to be successful, restocking of weasels should be done with young animals, which are preferably released during the season with abundant food resources.

Terrestrial hermit crabs use mollusc shells to protect their soft bodies from predation and desiccation, but their use is costly. The energetic short-term cost of using shells has been demonstrated, yet this could theoretically be overcome by increasing feeding rate or food quality. In the long term, shells have the potential to constrain growth, which may in turn have a negative effect on fitness. Thus crabs should choose the lightest (least expensive to carry) shell amongst those of a size that permit growth. Since in nature lighter shells are also thinner-walled, these may provide insufficient protection from predation or desiccation, facing the crabs with a trade-off between protection and growth. This potential trade-off was investigated in the terrestrial hermit crab Coenobita compressus. Crabs were individually maintained in captivity for a variable period of between 1 and 7 months, during which light or heavy replicates of the preferred shell were available. In a second experiment, crabs were given a choice between a thick (and heavy) or a thin (and light) shell. In addition, the resistance and water retention capacity of thin and thick shells was compared. As predicted, crab growth was negatively correlated with the weight of the shell used, but crabs rejected the thin (light) shells. Thin shells were more likely to break when crabs used the normal ‘rolling’ behaviour in response to perceived threats. In addition, thin shells lost water at a faster rate than thick ones. Since two putative functions of shell use in terrestrial hermit crabs are protection against predation and against desiccation, it is inferred that the preference for shells of intermediate weight in C. compressus results from a balance between the need to grow and the cost of carrying a brittle shell that is not sufficiently water tight.

In this study the diet of otters Lutra lutra was examined following the establishment of a population of non-native ruffe Gymnocephalus cernuus in Loch Lomond, Scotland. Otter spraints (n=453) were collected at monthly intervals from four sites during 2002. Overall, 98% of spraints contained at least one species of fish, invertebrates were found in 49%, 17% contained amphibians, while mammals and birds were found in 9%. The most frequent prey from all sites were ruffe, which were found in 69% of spraints. Eel Anguilla anguilla, cyprinids (roach Rutilus rutilus, dace Leuciscus leuciscus and minnow Phoxinus phoxinus) and Salmo spp. were also relatively common and were recovered in 60%, 35% and 33% of spraints, respectively. Northern pike Esox lucius (14%), perch Perca fluviatilis (12%), stickleback Gasterosteus aculeatus (9%), powan Coregonus lavaretus (14%) and lampreys Lampetra spp. (2%) were less common. The fact that ruffe were the most frequent prey in otter spraints in all regions and in all seasons of the year indicated that they are one of the most important prey for otters in Loch Lomond at the present time.