The Chinese jumping mouse Eozapus setchuanus (Pousargues, 1896) is endemic to the eastern border of the Tibetan plateau in China. It belongs to the Dipodidae family (Zapodinae sub-family) (Wilson and Reeder, 2005), among which the monotypic genus Eozapus is endemic to central China (Wilson and Reeder, 2005). Only about a dozen specimens are known to have been collected and deposited in Museums (Nowak, 1999). They come from elevations of 3,000–4,000 m, and stream bank in mountainous cool forests is the putative preferred habitat described by Nowak (1999). Still now, this species is reported to be rarely collected (Sung, 1998, in Amori and Gippoliti, 2003). Almost all published information concerns small mammal inventories or checklists at the regional scale, and atlases in which the presence of E. setchuanus is reported (Zhang, 1997; Wang, 2003; Qi et al., 2004; Zhang and Hu, 2004; Liu et al., 2005; Qi et al., 2005; Smith and Xie, 2008). To the best of our knowledge, no detailed information exists on its habitat requirements, life history traits, or population status. These data are however needed since the IUCN (World Conservation Union) designates E. setchuanus as vulnerable (category VU A1c), facing a high risk of extinction in the medium-term future because of human induced forest loss and degradation (Baillie, 1996). Its status was assessed in 1996, and its population trend is unknown (Baillie, 1996). Conservation actions towards this species must be grounded on a detailed knowledge about its ecology.
We report descriptive data on E. setchuanus which were collected by our research team as part of small mammal community surveys conducted in Central China between 1996 and 2005 (Giraudoux et al., 1998; Giraudoux et al., 2003; Giraudoux et al., 2006; Raoul et al., 2006). Details of trapping procedure are given by Giraudoux et al. (1998) and Raoul et al. (2006). Animals were sampled in July 1996, September 2003, June 2004, and September 2005. We compare these results with information available from the literature. Museum specimens were also used as information source. We provide information about life-history traits and habitat of E. setchuanus and present the first description of its karyotype.
The spatial distribution of roosts in relation to foraging habitats has never been investigated for Vespertilio murinus and the nocturnal roosts used by this species remain unknown. In order to improve knowledge of the species' ecology and to provide tools for its conservation, we mapped each known day roost of a breeding population located at the western limits of the species' distribution and measured the shortest distance between the roosting sites and the foraging habitats. We also radio-tracked 7 females in different reproductive states in order to identify, to quantify the utilisation and to assess the biological importance of their nocturnal roosts. Our results revealed that the day roosts were located close to a large lake and that the bats roosted mainly in trees of a riparian forest during the night. Implications for the conservation of this bat species are discussed.
SummaryOver several decades American mink (Mustela vison) colonised large parts of northern Eurasia where they occupied species-specific habitats and caused severe problems in indigenous wild life communities. These populations originated from accidental ranch mink escapes or deliberate release. It is of general interest to characterise their taxonomic state in contrast to individuals from North America. Therefore, comparative investigations were accomplished on skulls of adult mink with Canadian and Belarus origin using 18 parameters and the total body weight. The diverse parameters were allometrically analysed in relation to greatest skull length and to body size additionally. As a result the Belarus mink skulls are significantly different from the Canadian and the degree of difference is largely above the level between Canadian subspecies (e. g., M. vison lacustris versus M. v. energumenos). Independent of body size Belarus mink skulls clearly are shorter in the facialis part including tooth row and evidently smaller in brain cavity size. The differences are identical with intraspecific changes due to the process of domestication leading from the wild to the ranch mink. Altogether the Belarus individuals still resemble ranch mink in skull configuration although being feralised for many generations. Zoological consequences of this fact are further discussed and the scientific name Mustela vison f. dom. fera is proposed to characterise the Eurasian wild populations and discriminate these from the autochthonous ancestors in North America.
SummaryRhagomys rufescens is one of the rarest species of the South American mammalian fauna. This scarcity has determined a lack of studies on the natural history and systematic relationships of this presumptive Atlantic forest endemic. Here we report on two recently collected specimens of Rhagomys rufescens, redescribing its morphology and discussing its phylogenetic relationships on the basis of Cytochrome b sequence data. Morphological comparisons with selected Atlantic forest species reveal that R. rufescens displays a remarkably divergent set of character states, such as a unique molar design with diagonally projected cusps and an extremely reduced first digit of hindfoot with a nail instead of a claw, resembling an additional plantar pad. These and other morphological features are suggestive of an arboreal habitus and, at least with respect to its molar morphology, a rather insectivorous diet. Molecular analysis did not allow unequivocal allocation of Rhagomys either to the oryzomyine or to the thomasomyine suprageneric assemblages, as a result of its high level of evolutionary divergence. Rhagomys seems to represent a rather divergent lineage with no clear relation to any extant sigmodontine tribe.
The present study aimed at assessing genetic purity of black wildebeest (Connochaetes gnou) at Abe Bailey Nature Reserve, Gauteng Province, South Africa, using a multilocus microsatellite approach. Five loci were studied in black and blue (C. taurinus) wildebeest, the latter being a closely related species and known to produce hybrids with the morphologically very similar black wildebeest. In fact, the entire national black wildebeest population of South Africa potentially contains a significant proportion of introgressed blue wildebeest genes. In our case, eight out of 39 alleles were unique to black and 22 to blue wildebeest, with nine alleles shared between pure populations of the two species in line with their taxonomic proximity. A possible limited past introgression of blue wildebeest genes into the Abe Bailey population, corresponding to documents on population history, was only supported by the presence of a single allele otherwise exclusively found in samples of four pure blue but not in samples of two pure black wildebeest control populations. However, an assignment test and coefficients of population divergence did not support an extended introgression of C. taurinus alleles into the C .gnou population under study. Average heterozygosity at Abe Bailey proved to be intermediate between black and blue wildebeest, the latter species generally harbouring more genetic variation than the former owing to larger population sizes and the absence of population bottlenecks in historical times. The implications of our data are discussed with reference to the persistence of introgressed genes and the conservation of pure black wildebeest gene pools.
SummaryEuropean rabbits, Oryctolagus cuniculus, are the basic prey of several endangered predators and an important hunting bag in the area of its origin in southwestern Europe. Conversely, they are considered an undesirable species in other areas where they were introduced. Therefore, there is great interest in understanding the factors that influence population dynamics and abundance of this species. I studied the effects of relatively common heavy rains on inter-annual variations in rabbit density in four habitats of Doñana National Park and surrounding areas (southwestern Spain) during several years when rainfall was either lower or higher than average. I estimated spring and autumn rabbit densities by line transect sampling between autumn 1993 and autumn 1998, and counted rabbit warrens and entrances in two of the habitats (one with and the other without scrubland vegetation) in 1995, 1996 and 1997. Rabbit density significantly decreased in all habitats during the rainy years, densities being on average 5.3 and 4.6 times lower for spring and autumn censuses, respectively. Both number of warrens and entrances significantly decreased after two consecutive years of heavy rain in both habitat types, although in the scrubland habitats some recovery was observed during the second consecutive year of heavy rains. The area where warrens were apparently free of the effects of rains was only between 2.7 and 3.8% in the open habitat and 21.5% in the scrubland. At least for the open habitat, no clear relationship was observed between the height above sea level and whether warrens were affected by rain or not. The results indicate that heavy rains may be an important factor decreasing rabbit density, at least in flat areas, by negatively acting on warrens during the breeding period.
SummaryThe relationship between the abundance of two rodents, the wood mouse Apodemus sylvaticus and the Algerian mouse Mus spretus, and habitat characteristics were studied in Great Kabylia (Northern Algeria) at the end of the breeding season, when mice densities were at their highest level. Eleven habitat characteristics were recorded to describe 18 sampling sites. A linear multiple regression analysis revealed that the abundance of wood mice associated with rocks and stone blocks, and with low woody vegetation. Algerian mice were associated with a low cover of high woody vegetation, and with bare ground. Other habitat characteristics, such as modification of land by human activities, were also important and affected the abundance of these two species. These patterns are discussed in relation to the feeding habits and the anti-predatory behaviour of the species. The interspecific relationships of the two species are hypothesised.
Riverine refuging by non-human primates, with focus on proboscis monkeys, was studied in a forest along the Menanggul River, Sabah, Malaysia from May 2005 to 2006. The results of the primate census indicated that not only proboscis monkeys but also sympatric primates inhabiting the study site preferred to utilize the riverine habitat for night-time sleeping, though the frequency of riverine usage was different among these sympatric primates. Four predation-related events in the study site and two additional predation reports at other study sites involving clouded leopards suggest a relatively high predation pressure in proboscis monkeys relative to other sympatric primates. Riverine refuging, which represents a strategy of long-range visibility, may provide non-human primates including proboscis monkeys with the common benefit of an effective means of predation avoidance. In addition, a one-male group of proboscis monkeys was studied to clarify the effects of food availability and air temperature on riverine refuging. Proboscis monkeys spent more time in the inland habitat, though the food availability was not much different between riverine and inland habitats, indicating that food availability is not a fundamental factor in their preference for riverine habitat. Air temperature only had a small effect on their preference for the riverine habitat. However, to clarify the reasons why riverine refuging is more common in proboscis monkeys than in sympatric primates, further investigation is needed.
Non-geographic morphometric variation, particularly at the level of sexual dimorphism and ontogenetic (age-related) variation, has been documented in rodents, and useful for establishing whether to analyse sexes separately or together, and for selecting adult specimens for subsequent data recording and analysis. However, such studies have largely been based on traditional morphometric analyses of linear measurements that mainly focus on overall size, rather than shape-related morphometric variation. Unit-free, landmark/outline-based geometric morphometric analyses are considered to offer a more appropriate tool for assessing shape-related morphometric variation. In this study, we used geometric cranial morphometric analysis to assess the nature and extent of sexual dimorphism and age variation within the Tete veld rat, Aethomys ineptus (Thomas and Wroughton, 1908) from southern Africa and the African Nile rat, Arvicanthis niloticus (Desmarest, 1822) from Sudan. The results obtained were in turn compared with previously published results based on independent geometric and traditional cranial morphometric data from the same sampled populations examined in the present study. While our geometric morphometric results detected statistically significant sexual dimorphism in cranial shape within Ar. niloticus only, previously published results based on traditional morphometric data failed to detect significant sexual dimorphism within this species. However, similar to previously published traditional morphometric data, our geometric morphometric results detected statistically significant age-related variation in cranial shape and size within both Ae. ineptus and Ar. niloticus, with individuals of age classes 5 and 6 being considered to represent adult specimens. Our results highlight the importance of carefully evaluating both size- and shape-related non-geographic morphometric variation prior to the analysis of geographic variation and the delineation of species. Erroneous conclusions of non-geographic variation may have implications in the interpretation of geographic and evolutionary processes that may be responsible for morphological differences at both the inter- and intra-specific levels.
In this study, information concerning home range size and overlap of Calomys venustus (Thomas, 1894), in relation to sex, population size, and breeding periods is provided. The present study was carried out on a railway bank in southern Córdoba Province (Argentina), between October 1994 and September 1997, using the capture-mark-recapture method. Home range size in C. venustus depended on breeding period and population size, and was independent of sex. The degree of home range overlap was dependent on breeding and non-breeding periods and overlap type (intra- or intersexual), but was independent of population density. During the breeding period, females showed a small degree of intrasexual home range overlap. In general, male home ranges largely overlapped with females. The conclusion is that differences in home range size of C. venustus could be determined by season and population size. Moreover, the degree of inter- and intrasexual home range overlap during the breeding period suggested that males and females of C. venustus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by female distribution.
The European roe deer population in Portugal is on the southwestern edge of its distribution. Understanding limiting factors that act on these populations enlightens both local aspects concerning their conservation and wider scale aspects of the species bioclimatic envelope, which is crucial for being better able to predict the impacts of environmental change. Accordingly, a survey was conducted to explore roe deer distribution in a 75,000 ha area located in Trás-os-Montes region, a Mediterranean landscape in the northeast of Portugal. Pellet-group counts were used to examine how roe deer distribution was related to habitat structure and composition, landscape structure, and human disturbance. The analysis considered two spatial scales: habitat patch and the wider landscape. At the patch scale, roe deer distribution was positively associated with high density of shrubs and with increasing distance from roads. At the landscape scale, roe deer distribution was negatively associated with spatial heterogeneity, namely mean shape index. Our findings suggest that landscape structure, vegetation composition and distance to roads are all important factors influencing roe deer distribution, highlighting the importance of multi-scale approaches.
SummaryThe purpose of this study was to assess the occurrence of food preferences in captive pacas, a frugivorous New World rodent species, and to analyse whether these preferences correlate with nutrient composition. Using a two-alternative choice test six Agouti paca were repeatedly presented with all possible binary combinations of 12 types of food which are part of their diet in captivity and found to display the following rank order of preference: mango > avocado > melon > papaya > banana > orange > pineapple > tomato > apple > cucumber > carrot > chayote. Correlational analyses revealed that this preference ranking showed a significant positive correlation with total energy content, irrespective of the source of energy as neither total carbohydrate content nor protein or lipid content were significantly correlated with food preference. Further, food preferences were significantly negatively correlated with water content. No other significant correlations between food preferences and any other macro- or micronutrient were found. These results suggest that pacas, despite their dietary specialisation on ripe and carbohydrate-rich fruits, are opportunistic feeders with regard to maximizing their net gain of energy.
Long-term monitoring of small mammal populations is very important to understand the variations in temporal abundance on a large time scale, which are related to ecological, economic and epidemiological phenomena. The aim of this study is to monitor the populations of the marsupials Didelphis aurita and Philander frenatus and the rodents Nectomys squamipes, Akodon cursor and Oligorysomys nigripes in a locality of typical Brazilian rural landscape, Sumidouro Municipality, Rio de Janeiro State, Brazil. A mark-recapture study was conducted during five years. We analyzed the population dynamics, the reproduction and age structure of these species. Both marsupials presented higher population sizes in the end of wet period and beginning of the dry period, which can be explained by the seasonal reproduction which begins in the middle of the dry period and ends in the last months of the wet period. N. squamipes reproduced throughout the year but mostly during rainy periods, due to the close association of this rodent to resources found in the water. Higher survivorship and recruitment rates were in the end of the wet season. The rodent A. cursor had an opportunist reproduction, resulting in high turnover rates. Survivorship increased with the effects of the dry periods. O. nigripes showed a clear annual pattern of population cycle with peaks during the dry season. The rodents did not show potential to present outbreaks and become agricultural pests. The annual population cycles of O. nigripes and the unique peak of A. cursor population during five years highlight attention to their importance as wild reservoirs of the hantavirus disease. Their ecological characteristics associated to their opportunistic behavior make these species prone to be good reservoirs of zoonoses.
SummaryFeeding habits of sympatric species of small mammals in agroecosystems of central Argentina were analysed using micro-histological analysis of stomach contents. All small mammal species were omnivores, but species changed their diets in relation to the habitat disturbance level. Calomys species showed more dietary overlap in greatly and moderately disturbed habitats than in less disturbed habitats. Calomys species and Akodon dolores behaved in opposite ways. The high degree of dietary overlap among Calomys species was explained by the chance disturbance hypothesis, and their low degree of dietary overlap by classical resource partitioning. The high dietary overlap between Calomys species and A. dolores was explained via the generalization-specialization hypothesis.
Sloths are arboreal mammals strictly dependent upon forested habitats. The southern part of the state of Bahia in northeastern Brazil harbors important forest remnants and the highest genetic diversity known for the maned sloth (Bradypus torquatus), an endangered species endemic to the Atlantic forest. Large extents of cacao agroforests (cabrucas) connected to forest patches mitigate the effects of fragmentation in this region. We radio-tracked three maned sloths during 40 months in a cabruca at the vicinity of Una Biological Reserve, southern Bahia, and estimated their home range using two commonly employed estimators (minimum convex polygon (MCP) and kernel). Overall cabrucas comprised a significant portion of the home range of the three study animals (MCP: 7–100%) and at least a third of the areas of more intensive use (kernel: 27–99%). The tagged sloths used cabrucas more than expected according to the availability of this habitat in their home range and in the surrounding landscape. In addition to the tagged individuals, maned sloths were observed five times in the study area, twice in cabrucas. Eleven tree species present in cabrucas were used as food sources by maned sloths. Results indicate that biologically rich cacao agroforests immersed in a landscape still largely composed of native forests, as is the case here, can provide habitat for the maned sloth. This finding spells good news for the conservation of this species, as southern Bahia is one of the most important strongholds for the maned sloth. However, further actions are necessary to protect the species from local extinction, including active management of protected areas, forest fragments, cabrucas and pastures in an integrated, landscape-level manner.
Moose (Alces alces L.) were among the first Large mammals to recotonize Central Europe after the Last glaciation. Already during the Allerod they established themselves in most parts of the area. In the early Holocene their distribution range extended from the Pyrenees to Denmark and from Austria to Great Britain and also covered eastern Central Europe where they still occur today. In the Preboreal, the moose slowly vanished from the southwestern parts of its distribution range, Leading to its extinction in France and, later, in England. During the Atlantic period, the moose died out in Large parts of Denmark and population densities apparently decreased in the rest of Central Europe as well. Around the birth of Christ only relict populations were left in western Central Europe, which finally became extinct in early medieval times. In Thuringia and in the region northeast of the river Elbe as well as in central Poland, some stocks persisted until the high and Late Middle Ages. The causes of the gradual extinction in Central Europe during the Holocene are complex. Changes in vegetation, climate and sea-level, the increasing fragmentation of habitat through human activities and hunting were, at different times, important factors. In the recent past, however, moose have repeatedly migrated from the east towards the west. The development of its distribution range since the end of the Second World War as well as experiences with Scandinavian populations show that moose are able to thrive in close proximity to humans and that a future expansion of its distribution range towards the west seems possible. (c) 2005 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. ALL rights reserved.
A total of 472 red deer, Cervus elaphus, from 16 free-ranging populations in France were examined for genetic variability and differentiation at 7 enzyme loci known to be polymorphic in this species. In addiditon, 73 specimens from 14 populations were examined for mtDNA differentiation using 16 six-base cutting restriction enzymes which, on the basis of 69 restriction sites, yielded altogether 5 haplotypes showing a quite variable distribution. Genetic variability within populations was quite similar, especially as far as allozymes are concerned. However, both marker systems revealed considerable genetic differentiation even at a small geographic scale, possibly suggesting that habitat fragmentation has already caused genetic isolation of local populations.
As a consequence of persecution and habitat fragmentation, wildcats (Felis silvestris silvestris) in Western Europe have experienced a severe reduction in population numbers and sizes. The remaining wildcat populations are considered to be endangered by losses of genetic variability and by hybridisation with free-ranging domestic cats. To investigate genetic diversity within and among wild and domestic cat populations in Germany and to estimate the extent of gene flow between both forms, we analysed a total of 266 individuals. PCR-amplification and sequencing of 322 base pairs of a highly variable part of the mitochondrial control region (HV1) of 244 specimens resulted in 41 haplotypes with 31 polymorphic sites. Additionally, eight microsatellite loci were examined for those 244 cats. Moreover, a total of 46 wildcats and 22 domestic cats could be genotyped for 13 polymorphic out of 31 enzyme loci. Genetic variability in both groups was generally high. Variability in domestic cat populations was higher than in wildcat populations. Almost no differentiation between domestic cat populations could be found (FST for microsatellites=3%). In contrast, wildcat populations differed significantly from one another (FST for microsatellites=9.55%) Within the smaller wildcat populations, a reduction of genetic diversity was detectable with regard to the nuclear DNA. Wildcat and domestic cat mitochondrial haplotypes were separated, suggesting a very low level of maternal gene flow between both forms. In microsatellites and to a somewhat lesser extent in allozymes, wildcats and domestic cats showed distinct differentiation, suggesting an only low extent of past hybridisation in certain populations. The microsatellite data set indicated a significantly reduced effective population size (bottleneck) in the recent past for one German wildcat population.
SummaryFrom the birth season in the spring until the beginning of rut in the autumn, individually marked chamois (Rupicapra rupicapra rupicapra) were observed in the Swiss National Park. The focus was on the spatial patterns and habitat characteristics of three chamois classes: females with young, females without young though sexually mature, and adult males.The summer home ranges of females with young were larger and overlapped more than those of females without young. In comparison, males had extremely small territories. Within the study area, some sporadically observed females were never seen to impinge on the home ranges of the regularly observed females. It must be inferred that they belong to other subpopulations. Habitat parameters provided little evidence for individual differences between the members of a given class: females with young, unlike females without young, generally avoided exposed places, whereas males seemed to favour them. There were also distinct grouping patterns: females with young and without young shared their ranges with other females, independently of the animal class they belonged to, but females with young stayed in larger groups than females without young, whereas males were mostly solitary.It is inferred that females with young displayed a spatial behaviour that allows best possible protection and feeding conditions for their young, whereas females without young and males try to build up fat reserves during summer. The competition for food between females with overlapping ranges and the social interactions between males, apparently reduce the survival rate of chamois. Therefore, the territorial behaviour is likely to play an essential role in the natural regulation of the chamois population.
A community of middle-sized and larger mammals was studied in a seasonally dry forest in the far north of the Brazilian Amazon. Diurnal and nocturnal surveys were carried out through the linetransect method, in 5 different forest types along a 10-km transect. Data were collected an density, biomass, and use of the forest types, and forest strata by the mammals. The terrestrial community of mammals was more abundant than the arboreal one, with ungulates contributing to the bulk of the biomass, as a result of Maracá being highly seasonal Overall densities were lower than in other sites in the neotropics, varying from 90.2 ind/km2 in mixed forest, to 159.9 ind/km2 in Terra Firme forest, whereas biomass, due to the contribution of large mammals, was much higher (2613.2 kg/km2 in mixed forest, and 4351.6 kg/km2 in Terra Firme forest). This study confirms that the animals surviving in larger numbers in these highly seasonal forests, where food productivity may be very low during the dry season, are those that have larger home ranges and travel longer distances in search of food.
Food habits of the American mink Mustela vison were studied based on the analysis of 2364 scat samples, collected at three lakes in Northeastern Poland. The mink preyed on a wide range of prey, but two types of prey, amphibians and fish, dominated in the diet of the mink during all the seasons. Frogs, and first and foremost, the common frog Rana temporaria, were hunted by the mink, mainly from the late autumn until the early spring, and comprised up to 83.9% of the prey biomass (the multiannual average for November-December at the Majcz Wielki Lake). The most frequently eaten fish were cyprinids and percids. Seasonality of fish consumption by mink was not as well pronounced as in the case of amphibians. At the first two lakes, fish were hunted mainly in the winter and in the early spring, whereas at the third lake in the summer. The highest multiannual average share of fish in the diet of the mink was recorded in March-April at Lake Tuchlin (69.2% of the prey biomass). Crayfish, which were recorded in the diet mainly in the late spring and in the summer, comprised up to 59.6% of the prey biomass for May-June at the Majcz Wielki Lake. Birds, mammals and insects were supplementary food for the mink. During the breeding season, mink predation on waterfowl and their broods was correlated with the abundance of crested grebe Podiceps cristatus and coot Fulica atra nests in the area. The diet of individual mink varied considerably and the share of birds in the diet of the mink was related to the distance from individual mink dens to the colonies of waterfowl. In May-June, adult birds, chicks and eggs comprised up to 73.6% of the prey biomass of a female mink that inhabited a den located 100 m from the colony's edge. At all three lakes, the diet of the mink was the most diverse in the late spring and in the summer. In May-August, the values of the mink food niche breadths were about twice those noted in winter months.
The effect of an artificial, unchanging photoperiod regime was examined in comparison to a natural photoperiodic regime on the reproductive pattern in Antechinus flavipes, a small dasyurid marsupial which in the wild has a short, highly synchronized mating period. Females held under a photoperiod of LD 12:12 showed delayed sexual maturity and only one individual entered oestrus, about 3 weeks after females under natural photoperiod. Oestrus could be induced in the remaining females by increasing the photoperiod by 1 min/day for at least 3-4 weeks. In contrast to the females, males under artificial and natural photoperiod showed a similar pattern of maturity and decline of reproductive condition and senility. Only some aspects of sexual maturity were delayed and others were unsynchronized in males under LD 12:12 regime compared to the males held under the natural photoperiod. Our study suggests that, especially in females, changing photoperiod is important in synchronizing reproductive events in A. flavipes.
SummaryYoung of precocial species depend on their locomotory abilities to follow their mother to foraging areas, and to avoid predators. We measured for the wild guinea pig (Cavia aperea), a relatively small species (adult mass 400–600 g) with particularly precocial young, how running ability develops with age and how it compares to adult performance. We also asked to what extent females are impaired in their locomotor performance when pregnant, and tested how high adults can jump. Animals used trot and gallop for most locomotion except when calmly foraging. They jumped to a maximal height of 60cm from a standing start. Maximal escape speeds of adults averaged 4.12 m/sec, peak velocity measured was 6.0 m/sec. Newborn young, weighing only 77 g, were able to run at speeds up to 2.55 m/sec, and reached adult levels (about 4.0 m/sec) when only 20 days old. This is partly explained by a positive allometry of leg length in comparison to mass. Locomotion of wild guinea pigs develops in a highly precocial manner and appears adapted to allow short bouts of high burst speed. Running speeds of adults are similar to those of similarly sized sciurids.
Although it is broadly accepted that small mammals often climb trees, only few studies explore arboreality in woodland rodents systematically. Here, we investigate the three-dimensional habitat use of wood mice Apodemus sylvaticus and bank voles Myodes glareolus at three different sites in Wytham Woods, Oxfordshire, under varying environmental conditions. A total of 12 trapping sessions was carried out between March and September 2003 and 2004. During each session, 100 Longworth live-traps with shrew escape holes were set in a 25-point-grid for 3 succeeding nights. Each time, 50 traps were placed on the ground, and 50 in surrounding trees at heights of 30-250 cm. Wood mice were significantly more arboreal than bank voles, and male wood mice spent significantly more time in trees than did females. Arboreality in bank voles occurred only under high population densities and food shortage, and both species were significantly more arboreal in woodland with dense understorey. Thus we conclude that while arboreality is predominantly a result of inter- and intra-specific competition, of the two species we studied, only wood mice, being more agile, can afford to utilize trees without getting caught by predators, and that sex differences are due to male territoriality. Estimates of population sizes and distribution, as well as studies of inter-specific interactions and socio-spatial behaviour are presumed to be affected by these results, and are currently likely to underestimate rodent numbers considerably. (c) 2007 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.
SummaryAlthough there have been several reports on the structures of the lacrimal apparatus of the Chiroptera, there has been very little discussion about its morphological diversity and potential phylogenetic implications. Histological sections were used to document the anatomy of the lacrimal-conducting apparatus (LCA) in representatives of 44 chiropteran genera, including, for the first time members of Taphozous, Nycteris, Macroderma, Lavia, Hipposideros, Lonchophylla, Noctilio, Pteronotus, and Furipterus. To reconstruct the evolutionary history of the bat LCA, the distributions of the LCA features were mapped, using the computer program MacClade, onto the phylogenetic tree of SIMMONS and GEISLER (1998). The lacrimal-conducting apparatus in the Chiroptera ground plan, characterized by a well-developed nasolacrimal duct and a narial, nasolacrimal duct opening, is very similar to other eutherians. Nevertheless, several evolutionary transformations have taken place within the Microchiroptera: The nycterids and noctilionoids (phyllostomids + (mormoopids + noctilionids)) are characterized by apomorphic reduction of the LCA. However, there seems to be no correlation between the absence of the LCA and the life style of these bat groups. In rhinopomatids, rhinolophids and some megadermatids, the nasolacrimal duct is truncated, opening in a ventromedial recess of the inferior nasal meatus close to the entrance of the nasopalatine duct and the vomeronasal organ. Similarly, among Nataloids (e.g., Natalus and Thyroptera), the nasolacrimal duct is shorter and opens into the inferior nasal meatus, but it has no connection to the nasopalatine duct. In emballonurids, in which the vomeronasal organ is absent, the nasolacrimal duct opens into the nasopalatine duct (e.g., Taphozous, Saccolaimus) or very close to its nasal entrance (e.g., Coleura, Cormura, Rhynchonycteris).