The evolutionary history of the lion Panthera leo began in Pliocene east Africa, as open habitats expanded towards the end of the Cenozoic. During the middle–late Pleistocene, lions spread to most parts of Eurasia, North America, and may have eventually reached as far south as Peru. Lions probably evolved group-living behaviour before they expanded out of Africa, and this trait is likely to have prevailed in subsequent populations. The first lions were presumed to have been maneless, and maneless forms seem to have persisted in Europe, and possibly the New World, until around 10 000 years ago. The maned form may have appeared c. 320 000–190 000 years ago, and may have had a selective advantage that enabled it to expand to replace the range of earlier maneless forms throughout Africa and western Eurasia by historic times: ‘latest wave hypothesis’.

Photo-identification surveys of humpback whales Megaptera novaeangliae were conducted at West Greenland during 1988–93, the last 2 years of which were part of the internationally coordinated humpback whale research programme YoNAH, with the primary aim of estimating abundance for the West Greenland feeding aggregation. The area studied stretched from the coast out to the offshore margin of the banks, determined approximately by the 200 m depth contours, between c. 61°70′N and c. 66°N. The surveys were conducted between early July and mid-August and 993 h were expended on searching effort. A total of 670 groups of humpback whales was encountered leading to the identification of 348 individual animals. Three areas of concentration were identified: an area off Nuuk; an area at c. 63°30′N; and an area off Frederikshåb. Sequential Petersen capture–recapture estimates of abundance were calculated for five pairs of years at 357 (1988–89), 355 (1989–90), 566 (1990–91), 376 (1991–92), and 348 (1992–93). Excluding the anomalously high estimate in 1990–91, the simple mean is 359 (SE = 27.3, CV = 0.076) and the inverse CV-squared weighted mean is 356 animals (SE = 24.9, CV = 0.070). These calculations lead us to conclude that between 1988 and 1993 there were 360 humpbacks (CV = 0.07) in the West Greenland feeding aggregation. Using the Cormack–Jolly–Seber model framework non-calf survival rate was estimated at 0.957 (SE = 0.028). Our data have low power (P < 0.3) to detect a trend of 3.1%, assuming the probability of a type I error was 0.05.

Bone mass is dramatically compromised during periods of weightlessness, inactivity, or bed rest. Animals that hibernate reduce their body temperature, heart rate and metabolic activity, and likewise lower bone turnover activity during their immobile state. Black bears Ursus americanus, however, do not hibernate, but rather overwinter by denning during which they maintain a nearly normal functional heart rate, cardiac output and temperature. Furthermore, markers of bone turnover in black bears are maintained during denning periods. Thus, the purpose of this work was to determine if the denning state of relative immobility in black bears results in changes in bone mass and bone architectural structure. Harvested forelimbs (ulna and radius) were compared between pre- and post-denning black bears using X-ray imaging, dual energy X-ray absorptiometry, and micro-computed tomography to quantify total distal forelimb bone mineral density, cancellous bone mineral density, bone mineral content, bone volume fraction, degree of anisotropy, structure model index, and trabecular thickness. No significant differences in any of the measured parameters were found in comparing radius and ulna from autumn and spring bears in this cross-sectional sample, suggesting that black bears did not experience a significant change in bone mass or architecture during denning. The statistical power for detecting a significant difference (P ≤ 0.05) for this sample was 0.8. The specific mechanism by which the preservation of bone was attained may be related to skeletal muscle interaction or circulating systemic hormones.

In polygynous mammals, fitness differences may reflect differences in phenotypic quality as well as experience. This study determines dominance hierarchy among female reindeer Rangifer tarandus from two experimental herds (consisting of c. 45 animals in each) during 2 consecutive years. The influence of body mass, antler size and age on social rank in the herds was investigated, first using simple regression analysis. The combined effect of body mass, age and antler size on female rank was further assessed using principal component analysis, as these three parameters were significantly correlated. The improved Laundau linearity index of c. 0.5 (Pr < 0.001) in both herds indicated that a substantial part of the hierarchies was explained by their linearity properties. Consistently, body mass, female age and antler size, as well as their combined effect (measured by the scores on the main axis, PC1), influenced social rank in all four groups. It was concluded that both body mass and age are good predictors of social rank in female reindeer, whereas antler size in comparison plays a less important role in herds with a ‘normal’ female age structure. This suggests that female antlers may have evolved in intersexual rather than intrasexual competition. The temporal variations in the importance of body mass and age, probably owing to variation in female age structure between the 2 years, calls for conservative interpretations of whether body mass or age is more important in determining social rank among female reindeer. This is confirmed by the PCA analyses, where all three variables contributed more or less equally to the first component, the size variable, which on average explained more of the variation in female rank than body mass and age, suggesting that phenotypic quality expressed as the combination of the three variables is a better predictor of social rank than the variables per se. Hence, general conclusions about social rank based on single studies including few animals may not be credible.

In the present study the evolutionary relationships among Cordylusniger–oelofseni–cordylus are investigated using molecular sequence data to: (1) estimate the divergence within this group; (2) date the origin of melanism in the clade and to evaluate possible palaeoecological events responsible for its evolution; (3) examine the systematic relationships among the three isolated populations of C. oelofseni that were previously shown to be polyphyletic using allozyme data. The recovered topology for the combined sequence data (16S and NADH dehydrogenase component 2 (ND2)) among C. niger–oelofseni–cordylus suggests that melanism evolved only once in the clade. The application of a molecular clock to the data demonstrates that melanism evolved during the Miocene epoch, 17–15 million years ago. We believe that the development of a cold-water current and upwelling system along the south-west coast of Africa during this epoch was instrumental in the evolution of melanism in this lizard clade and possibly also in other ectotherm clades with melanistic forms occurring in the area. The results show that C. oelofseni, as presently construed, is composed of three distinct evolutionary lineages, with no shared haplotypes present and marked sequence divergence. Two of the three lineages represent undescribed species. Cordylus cordylus is composed of two distinct clades, a montane clade and a coastal lowland clade. Cladogenic activity in mountain areas of the Western Cape in South Africa has been particularly pronounced and the systematic diversity of many taxa may have been underestimated.

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.

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.

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.

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.

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.

Senescence can be defined as accelerating phenotypic deterioration with old age. For traits that grow throughout life, such as the horns of some ungulates, senescence may be expressed as a decrease in annual growth rates, or an increase in asymmetry, in the years preceding death. Age-specific yearly horn-growth segments of 378 male Alpine ibex Capra ibex L. that died from natural causes were analysed in the Gran Paradiso National Park (Italian Alps). Horn annuli displayed fluctuating asymmetry. The hypothesis that asymmetry and size of the annuli of the horns could predict annual survival probability was tested. It was found that between 5 and 11 years of age, male ibex that grew shorter annuli than the average for the population had a greater probability of mortality over the following years than those with greater rates of horn growth. Horn asymmetry and mortality rates were not significantly correlated. Annulus size, reflecting the onset of senescence, seemed to be a better indicator of individual quality than annulus asymmetry.