Interspecific interactions between sympatric carnivores have important implications for intra-guild competition, epidemiology (here especially in the context of rabies and bovine tuberculosis), and strategies for species-specific population management. Data are provided on 135 interspecific encounters between at least 35 European badgers Meles meles and a minimum of five red foxes Vulpes vulpes, gathered with the aid of remote video surveillance at an artificial feeding site, and in the vicinity of six badger setts. We hypothesized that interspecific competition would be manifest in aggression and changes in vigilance and feeding, with the larger badger having the advantage, and we sought to explore differences in any such changes at the two types of site. Badgers were clearly dominant over foxes, fed in longer bouts and were less vigilant. At badger setts, once it was clear that the encounter was not going to escalate to aggression, each species was unaffected by the presence, proximity or orientation of the other. There are preliminary indications that foxes sometimes seek the company of badgers.

The highveld mole-rat Cryptomys hottentotus pretoriae is a social subterranean rodent that exhibits seasonal reproduction. Non-reproductive females remain anovulatory whilst in the confines of the natal colony. However, during the southern hemisphere summer, dispersal of non-reproductive females from the natal colony occurs with subsequent pairing with unrelated males. This study investigates whether the dispersing female highveld mole-rat is an induced or spontaneous ovulator. Eight non-reproductive females were removed from their natal colonies during the breeding season and housed individually for 5 weeks. Urine was collected every second day during the next 5 weeks of isolation. After this initial period, isolated females underwent one of three trials: two females were kept isolated without a male, three females were individually placed in chemical but not physical contact with unvasectomized males, while each of the remaining three females were allowed full contact with a vasectomized male. Urine was again collected every second day for a further 5 weeks, after which the females were killed. Both urinary progesterone profiles and histology of the ovaries revealed that the female highveld mole-rat is an induced ovulator. Females in physical contact with vasectomized males exhibited a significant increase in urinary progesterone concentration as well as the presence of corpora lutea in their ovaries, both indicative of ovulation. The act of coitus is necessary for ovulation to take place even though the males were not capable of fertilization. This is the first time induced ovulation has been shown in bathyergid rodents.

The effect of an open landfill and the seasonality of a tropical deciduous forest in Jalisco, Mexico, was tested on the home range and group size of coyotes Canis latrans under the Resource Dispersion Hypothesis (RDH), which proposes that in social carnivores dispersion of patches of limited resources determines home-range size, whereas independently, abundance of resources affects group size. The predictions in this study were that coyotes using the landfill, where food is available all year due to the continuous arrival of food wastes that are concentrated in a single patch, would have smaller, seasonally constant home ranges than coyotes living outside, where food is distributed in several patches. In this area, coyotes would increase their home ranges during the dry season due to seasonal changes in resource availability. Also, a larger coyote group size should exist in the landfill, where food abundance is greater. Home-range size and group size of coyotes living in and outside the landfill were estimated by radio-tracking. Home ranges of coyotes in the landfill varied from 0.9 to 9.5 km2, whereas home-range sizes of coyotes outside the landfill varied from 10.9 to 43.7 km2. Seasonality had no effect on the home-range sizes. We identified a group of four adult coyotes in the landfill and no group formation in coyotes outside. These results support the predictions about home-range and group size of coyotes in relation to landfill presence, and indicate that under the circumstances of our study, coyotes follow the postulates proposed by the RDH.

Recent studies have revealed that calcium limitation of avian reproduction may be a widespread phenomenon, affecting both egg properties and chick development. The effect of calcium shortage on the final body size of fledglings is usually rather weak, possibly owing to compensatory growth. Achieving full skeletal size is not, however, a reliable indication of complete ossification and it is possible that chicks with similar tarsus lengths are in different stages of skeletal development. We hypothesized that measuring plasma activity of the bone alkaline phosphatase (ALP), a highly specific marker for bone calcification, may reveal subtle developmental differences in full-grown fledglings, having experienced different levels of calcium availability during growth. In two seasons, a number of pairs of great tit Parus major were provided with calcium-rich material during the nestling period, while others were not supplemented (controls). While no significant differences in size of fledglings were detected between groups, bone-ALP activity at the pre-fledging stage was lower in the calcium-provided nestlings than in the control nestlings. This may indicate that supplemented chicks had completed the rapid phase of bone formation, but this process was delayed in controls. Measuring ALP as a marker of skeletal development expands our knowledge of how delayed skeletal development of chicks can result in protraction of the nestling period, thereby reducing the breeding success of adult birds.

The Iberian Peninsula comprises two distinct biogeographic areas: a temperate Atlantic Eurosiberian (north) and a Mediterranean (centre and south), and they provide very different biotopes, landscapes and prey for carnivores. One example is an abundance of the wild rabbit Orytolagus cuniculus in the Mediterranean zone, which contrasts with the Eurosiberian zone, where the rabbit is scarce. The feeding resource partitioning among four sympatric predators (red fox Vulpes vulpes, wild cat Felis silvestris, genet Genetta genetta and stone marten Martes foina) was analysed in the Peneda-Gerês National Park (north-west Portugal), located in the Eurosiberian region. Data on the spatial distribution of three important prey species (Apodemus sylvaticus, Microtus lusitanicus and Talpa occidentalis) were also collected to investigate their possible relationships with the feeding habits of each predator. Rodents are the staple prey for this guild of carnivores. Predators are able to supplement their diets with one or two secondary prey types: rabbits and arthropods by the largest carnivores (the red fox and the wild cat); insectivores by the small predators (the genet and the stone marten). These results contrast with the characteristic Mediterranean predator–prey features, where rabbits are the main support of carnivore communities. The feeding resource partitioning revealed a complex structure characterized by a dynamic niche differentiation and overlap, according to a seasonal pattern. To explain this pattern of resource exploitation two hypotheses are discussed in the light of the body size of predators and their use of space.

The relationship between masticatory morphology and chewing modes in all living genera of South American rodents in the family Octodontidae was analysed. Chewing directions and the patterns of molar occlusion were assessed. Factor and regression analyses of skull and jaw characters, and attributes of the adductor musculature, especially the line of action of masseters and pterygoids, were performed to check their relations with the chewing modes. Two basic chewing strategies are present in octodontids: oblique unilateral (associated with anterolingual jaw displacement, and alternate occlusion of left and right molar series), and propalinal bilateral (associated with mostly posteroanterior jaw displacement, and simultaneous occlusion). The skull and jaw characters examined are related only partly to these chewing strategies. The temporal pattern of muscle contraction provides a possible explanation for such a functional versatility. Propalinal grinding in octodontids could be achieved through simultaneous muscle contraction, with limited reliance on the lines of action of the involved muscles. Therefore, simultaneous contraction explains a similar propalinal masticatory mode in morphologically disparate genera. In accordance with phylogenetic information, oblique unilateral chewing is primitive in octodontids, and the derived propalinal mode has been developed independently at least twice in the evolution of the family.

The spatial dispersion and social interactions were studied in 11 neighbouring pairs of radio-tagged tawny owls Strix aluco in a deciduous wood in Denmark from 1998–2001. The numbers and shapes of territories were stable throughout the survey and similar to a mapping made 40 years earlier. The home ranges of mates were of equal size and overlapped 82% in summer and 56% in winter. The inter-mate distances were on average 2.7% shorter than expected by chance. The activity distribution of neighbouring pairs overlapped 9% (95% CI: 2–15%) on average. Males and females did not differ in overlap with neighbours, and there was a similar overlap between neighbours of the same and opposite sex. Both sexes vocalized more often in the peripheries than in the centres of their territory. The vocal activity during May–September varied extensively among years and months in accordance with variation in the density of juvenile floaters. Males and females vocalized equally often and were involved in disputes with neighbours at similar rates. Usually, neighbouring disputes involved either one individual from each pair or all four. Disputes involving all four owls more often involved chasing and fighting than those involving one owl only from each pair. The dispute rate between neighbouring pairs correlated positively with home-range overlap. The total annual mortality was 21% (95% CI: 6–33%). Dead owners were usually replaced within 1–2 months. Two out of four cases of radio-tagged owls disappearing from their territory because of natural causes was due to take-overs by invading owls, suggesting that the risk of losing fitness resulting from eviction was important. The apparent co-operative territorial behaviour of tawny owl pairs is probably due to improved resource holding potential of pair coalitions compared to single individuals.

Monomorphic lemurs of Madagascar allow us to investigate whether there are behavioural mechanisms that compensate for sex-specific differences in the costs of maintenance and reproduction in arboreal primates. Food selection of the pair-living Lepilemur ruficaudatus was studied in relation to food chemistry, and travel distances were measured as possible indications of differential investment in ranging activities (possibly related to the defence of territories and/or mating opportunities). Fourteen females and 14 males were radio-tracked for a total of 365 half-nights (from dusk to midnight or from midnight to dawn) at different times of the year (birth, lactation and weaning, pre-mating, post-mating). When based on monthly means, the two sexes did not differ in nightly travel distances. Food selection of females and males did not differ in relation to the chemical composition of leaves, but fruits consumed by females had lower fibre contents than fruits consumed by males. Even though other behavioural data are fragmentary, little evidence exists for behavioural mechanisms in L. ruficaudatus to compensate for the different energetic costs of females and males.

Two hundred and fourteen skulls of Asian deer species (Cervini) were measured and the resulting craniometric data analysed using multivariate statistics. Our results suggest that elements of skull shape as determined by morphometrics can be used as phylogenetic characters and depict phylogenetic relationships among Cervini deer species that is not far removed from the picture given by molecular studies and other characters. Morphometrics-based phylogeny was used in combination with other phylogenies and palaeoenvironmental reconstructions to investigate factors that may have influenced evolutionary changes. Our data indicate the need for a revision of the genus and subgenus level taxonomy of the Cervini.

The results of a study testing the hypothesis that wildcats Felis silvestris are rodent-specialist predators is reported. The diet of wildcats was studied in different habitats from central Spain where rabbits Oryctolagus cuniculus were either present or absent in order to explore whether the wildcat is a facultative or a rodent specialist. We predicted that if the wildcat was a rodent specialist there would be no differences in rodent composition in scats between areas with or without another profitable prey such as rabbits. To test this hypothesis, 239 scats were collected in two contrasting habitat types: Mediterranean vegetation areas, where rabbits were either present or absent, and Pyrenean oak forests, where there were no rabbits. All areas and habitat types were sampled in different seasons. The frequency of occurrence and biomass of different prey items and diet diversity were compared between habitats and areas with the presence/absence of rabbits. Wildcats consumed significantly fewer rodents in areas with rabbits than in areas where rabbits were absent, and diet diversity showed important seasonal variations. Values for diet diversity were lower in areas where rabbits were present. Thus it can be stated that wildcats do not specialize in rodents, and we suggest a facultative specialization on different prey items (rabbits or rodents) according to prey availability.

The size of reptile hatchlings can be phenotypically plastic in response to incubation temperature, and size is a trait likely to influence fitness – i.e. hatchling size is proposed as an indicator of quality. The parental and incubation temperature effects on the size of one of New Zealand's most biologically significant reptile species, the tuatara Sphenodon punctatus are investigated. Artificial incubation at constant temperatures is used to produce founders for new captive and wild populations of tuatara and to augment existing rare populations. We compare size of hatchling tuatara from artificial and natural incubation treatments. The relationship of hatchling size with incubation temperature and sex is examined, and we investigate whether our results support differential fitness models for the evolution of temperature-dependent sex determination in tuatara. Initial egg mass is the most important factor affecting size of hatchling tuatara and is still an important influence at 10 months of age. Incubation temperature does not greatly influence size of hatchlings, but significantly influences size by 10 months of age. Constant artificial incubation conditions result in larger, but possibly less aggressive, juveniles than those from more variable natural incubation conditions by 10 months of age. Evidence from size patterns of tuatara incubated in natural nests supports differential fitness models for the adaptive significance of temperature-dependent sex determination. Thermal variation has little effect on size of male hatchlings, but female embryos that develop in more stable thermal conditions, in more reliable sites for hatching, are bigger and have longer jaws.

Maximum likelihood (ML) and Bayesian inference (BI) analyses of the complete nucleotide sequences of the cytochrome b gene (cytb) were used to examine the phylogenetic position of the rare snake Xenophidionschaeferi within the alethinophidian snakes. The cytochrome b sequence of this representative of the poorly known family Xenophiidae was compared with those of a large and comprehensive suite of alethinophidian taxa. The research presented here represents the first time all families of alethinophidian and caenophidian snakes have been included in a single molecular phylogenetic study. Results from ML and BI analyses suggest a possible sister taxon relationship between Xenophidion schaeferi and the Bolyeridae. Moreover, strong statistical support also indicates that Xenophiidae is a member of a clade that contains Pythonidae, Loxocemidae, Uropeltidae, Xenopeltidae and Bolyeriidae. Additionally, maximum parsimony and BI analyses of previously published morphological data revealed that these anatomical character states and potentially low taxonomic sampling produced little phylogenetic information valuable to understanding the relationship of Xenophiidae among the Alethinophidia.

Mean depth and mean size of burrow system components, burrow-soil temperatures and actual diurnal temperatures, humidity and oxygen concentration in burrows of silvery mole-rats Heliophobius argenteocinereus were measured in two mesic areas in Malawi. Mesic tropic climate, together with soil and plant cover contribute to a diurnally and seasonally stable microclimate even in shallow burrows. Daily and seasonal changes of burrow temperatures were lower compared to those in bathyergids from temperate areas where ambient and burrow temperatures undergo larger fluctuations. Silvery mole-rats in Malawi are thus probably not distressed by these environmental factors.

Enamel hypoplasia, a developmental tooth defect, provides a permanent record of systemic stress during early life. The incidence and distribution of linear enamel hypoplasia has been used by anthropologists and palaeontologists to assess the health status of past populations but has not been applied by wildlife biologists studying extant animals. This study investigates enamel hypoplasia in 23 Giraffa camelopardalis skulls from wild and captive animals of various ages and sex to determine whether any systemic stress events are unique to life in captivity. Results indicate that wild giraffes are relatively stress-free as they do not have linear defects. Based on the distribution of linear defects in other giraffes, three key stress periods during the first 6 years of giraffe life were identified. The first stress event occurs during weaning, the second at about 3 years of age and the third, which is the least common, at 4–5 years of age. All three stress events were observed in both male and female giraffes. This study highlights the usefulness of assessing enamel hypoplasia in both wild and captive animals as well as the need for further research on tooth developmental timings in many wild ungulates. Some left–right asymmetry was observed in the development of linear and non-linear defects, which has implications for the aetiology of these defects.

Habitat use by the boto, or Amazon river dolphin Inia geoffrensis, was investigated in and around the Mamirauá Reserve, Brazil. Largely forested with numerous channels and lakes, Mamirauá comprises a variety of seasonal floodplain habitats known collectively as várzea. The annual cycle of flooding in this region (amplitude 11–15 m) dominates all life. Profound seasonal differences in dolphin density between habitats were consistent with known fish movements, in turn dictated by changes in water level and dissolved oxygen. An exodus of botos from floodplain to river at low water prevents dolphins being trapped in areas that become entirely dry. Densities of botos in floodplain channels were seasonally higher (up to 18 km−2) than reported for any cetacean worldwide. Adults were largely segregated by sex except at low water. Females and calves dominated in chavascal habitat–the areas most remote from rivers, which were preferred by males. Probable causes of this segregation are the energetic requirements of calves and the safety of females and/or calves from male harassment. Some 80% of botos occurring on rivers were within 150 m of the margins. The reliance of adult females and calves on várzea in a region with exceptional dolphin densities demonstrates the importance of floodplain habitats for the boto, and may be the key determinant of this species‘ distribution.

The tremendous capacity of the chromatophore system in cephalopod skin to change its colour across space and time has allowed these animals to produce complex visual displays to conspecific and heterospecific targets, including the aptly-named ‘passing cloud’. This display has been suggested as an interspecies communication, but it has not been investigated in detail. Octopus cyanea produced dark passing clouds during hunting of crab prey, typically after a web-over capture attempt. Clouds moved not randomly but forward along the mantle, over the head and down the outstretched arm web, and were often accompanied by white margins that enhanced their appearance by intensity contrast. This visual display is presumed to be a startle attempt, producing apparent movement by selective sequential chromatophore expansion to induce a crab to move without the drawback of motion by the octopus itself.

Aristiform spines of the rodents Niviventer fulvescens, Maxomys surifer, Hoplomys gymnurus and 17 species of Proechimys (representing both recognized subgenera and all nine species groups) were studied qualitatively using scanning electron microscopy (SEM) and quantitatively by measuring seven linear dimensions. SEM was used to examine spine tips, bases, longitudinal furrows and cross sections. Spines of the murid rodents N. fulvescens and M. surifer differed from those of the echimyid rodents H. gymnurus and Proechimys spp. in possessing a smaller base with a longer, narrower neck, scaled rather than ridged longitudinal furrows, and a solid internal core and large lacunae at the spine margins. Spines of H. gymnurus differed from those of Proechimys spp. in being considerably more robust with a stout neck at the base, an abruptly-tapering tip and a dense inner layer with a series of smaller lacunae at the spine margins. A factor analysis of spine measurements revealed major differences among N. fulvescens, M. surifer, H. gymnurus, the Proechimys subgenus Trinomys and the nine Proechimys species groups within the subgenus Proechimys. However, all Proechimys species groups clustered closely together. A discriminant function analysis of the nine Proechimys species groups provided generally limited discriminatory power. Although spines are distinct at the generic and subgeneric levels, spines may possess limited diagnostic structure at the level of species within the subgenus Proechimys.

The Australian gidgee skink Egernia stokesii is unusual among lizards in that it maintains stable social aggregations of related individuals. Experiments were conducted to investigate whether lizards living in groups gained benefits from the collective detection of approaching threats. In captive colonies, lizards living in a group detected an approaching threat earlier than lizards alone, and lizards basking in a group spent more time in a non-vigilant, eyes-closed, state than lizards alone. These results imply that individuals in this species gain from the enhanced vigilance associated with group membership. Since many juveniles remain within their natal groups, group vigilance may enhance inclusive fitness.

Dynamics of a rodent community were studied in the Negev Desert Highlands (Israel) during 8 years on 24 permanent 1-ha plots representing six main habitat types. Based on theoretical models of habitat selection, we hypothesized that niche overlap between species of the same spatial guild should increase with density faster than that between species of different guilds. Data were analysed using multivariate (principal component and discriminant) analyses to test the hypothesis. Density changes in most rodent species followed fluctuations in the amount of rainfall. Habitat niche breadth was density-dependent in six species and density-independent in four species. Significant habitat shifts and switches of spatial guild membership were found in three of 10 species. Pairwise values of habitat overlap were significantly and positively correlated with density only in species pairs where both species demonstrated density-dependent variation of habitat breadth. In most other pairs of species, overlap values were density-independent. Comparison of changes in average within-season values of habitat overlap with density within and among spatial guilds directly supported our hypothesis demonstrating faster increase of niche overlap with density between species of the same spatial guild than between species of different guilds.

The factors affecting habitat selection by smooth-coated otter Lutra perspicillata were studied along the Periyar Lake within the Periyar Tiger Reserve, Kerala, India, between November 2000 and April 2001. The importance of different habitat features influencing habitat selection was assessed using ordination technique. The presence of holts, spraint sites, grooming sites and footprints were considered as good indicators of the use of an area by the otters. For foraging, otters selected less rocky areas of the shallower parts of the lake, which are narrower and slanting. The number of streams joining these areas was more than on the other stretches of the lake and the bankside vegetation was dense. The deeper and wider areas of the lake were avoided. Holts were found in a variety of habitats, such as grass and Lantana thickets, rock crevices and under fallen logs and roots of standing trees at an average distance of 18 m from the water level. Grooming sites were characterized by high sand content and nearness to water.