bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal variation of predation on rodents and shrews by small African forest carnivores
Authors: Ray Justina C. 
Published: February 2006

AbstractAnalysis of 904 small carnivore scats collected over a two‐year period in a seasonal forest in the south‐western Central African Republic yielded the remains of 732 shrews, rodents (<1 kg), and bats comprising at least 34 species. Most scats belonged to the long‐nosed mongoose, Herpestes naso, the numerically dominant carnivore in the study area. Shrews were the principal small mammal prey with respect to number of individuals and frequency of occurrence. The mean monthly frequency of occurrence of shrews was 21.7% and of small rodents (<100 g) was 20.8%. Both shrews and small rodents occurred significantly more often in scats collected during dry season months, and live‐trapping of rodents over a 22‐month period revealed similar peaks in availability. In contrast to many mammalian carnivores, shrews did not appear to be used as an alternative prey source: not only did consumption levels of both prey types fluctuate in synchrony, but the availability of rodents apparently had no effect upon the likelihood of including shrews in the diet. Preferential use of small mammals by long‐nosed mongooses was tested for the 10 rodent species for which abundance indices were calculated. Mongooses preyed selectively on several rodent species (Praomys spp., Deomys ferrugineus, Stochomys longicaudatus, and Grammomys rutilans), while the most common rodent in the study area, Hylomyscus spp., was found in scats at lower frequencies than expected. In accordance with the habitat specificities of these ‘preferred’ rodent prey, it is suggested that mongooses and perhaps other small carnivores were foraging in micro‐habitats characterized by higher‐than‐average vegetation understorey thickness where the simultaneous rate of encounter with arthropods, their main prey, and shrews was apt to be high.
Functional morphology, comparative behaviour, and adaptation in two sympatric subterranean rodents genus Ctenomys (Caviomorpha: Octodontidae)
Authors: Vassallo Aldo I. 
Published: February 2006

AbstractTwo species of tuco‐tucos, Ctenomys talarum and C. australis, overlap geographically in south‐eastern Buenos Aires Province, Argentina. C. talarum (100‐180 g) occupies habitats with clayey and harder soils, while the larger C. australis (300‐600 g) occupies sandy and quite friable soils. This study compares the digging apparatus and digging performance of both species, and also provides additional ecological data to describe the adaptations of both species. When confronted with sandy, friable soils, both tuco‐tucos exclusively use their forelimbs (‘scratch digging’ mode) to break the soil. When confronted with harder and clayey soils, C. australis used its forelimbs and, less frequently, its incisors, but no appreciable effectiveness was observed in breaking the soil. On the other hand, C. talarum behaved as a ‘scratch’ and ‘chisel‐tooth digger’ species, using both forelimbs and incisors to dig tunnels in extremely hard soils. C. talarum showed relatively larger forelimb extensors than C. australis. Moreover, I hypothesize that the structure of the ulna in C. talarum may increase the effective forces of the digital and carpal flexors, thus accounting for the enhanced digging ability in this species. Outward forces exerted by the distal elements (claws‐digits‐carpals) when forelimbs impact the soil appear to be a critical factor in loosening soil fragments. In addition, the increased upper incisor procumbency of C. talarum correlated with an effective chisel‐tooth digging behaviour. Finally, I briefly examine phylogenetic and biogeographical factors that may account for some C. australis morphological and physiological traits. It is suggested that the digging ability of C. australis could be a by‐product of its larger size, a likely adaptation to evade predation.
Demography of the Serengeti cheetah (Acinonyx jubatus) population: the first 25 years
Authors: Kelly Marcella J. , Laurenson M. Karen , FitzGibbon Clare D. , Collins D. Anthony , Durant Sarah M. , Frame George W. , Bertram Brian C. , Caro T. M. 
Published: February 2006

AbstractData are presented on the demography and reproductive success of cheetahs (Acinonyx jubatus) living on the Serengeti Plains, Tanzania over a 25‐year period. Average age at independence was 17.1 months, females gave birth to their first litter at approximately 2.4 years old, interbirth interval was 20.1 months, and average litter size at independence was 2.1 cubs. Females who survived to independence lived on average 6.2 years while minimum male average longevity was 2.8 years for those born in the study area and 5.3 years for immigrants, with a large proportion of males dispersing out of the Plains population. Females produced on average only 1.7 cubs to independence in their entire lifetime and their average reproductive rates were 0.36 cubs per year or 0.17 litters per year to independence. Variance in lifetime reproductive success in the cheetah is similar to that of other mammals.No significant negative correlations were found between adult cheetah population size and numbers of cubs reaching independence, implying that the Plains population had not reached carrying capacity. Annual numbers of adult female cheetahs only were correlated with rainfall. Adult female cheetah numbers were not correlated with adult female lion numbers on the Plains, however, reproductive rates of cheetahs were negatively correlated with the presence of lions while cheetahs had cubs. Moreover, cheetah reproductive success was lower during the period of high lion abundance (1980‐1994) than during the earlier period of relatively few lions (1969‐1979). Litter size at independence dropped from 2.5 to 2.0, lifetime reproductive success declined from 2.1 to 1.6 cubs reared to independence, and the reproductive rate (cubs/year) decreased from 0.42 to 0.36 from the earlier to the later period.Cheetah reproductive success showed little association with the presence of Thomson's gazelle at sightings except for a negative correlation between large numbers of gazelle (200±500) and reproductive success possibly because hunting success decreases with increasing prey herd size, or because cheetahs always lose in direct competition with other predators which are attracted to large congregations of prey. In addition, cheetah reproductive success was negatively correlated with the presence of Grant's gazelles (11 or more) perhaps because Grant's gazelles were more likely to occur consistently in dry areas.
Ontogeny of resistance to desiccation in the bush‐dwelling snail Theba pisana (Helicidae)
Authors: Arad Zeev , Avivi Tzameret R. 
Published: February 2006

AbstractThe distribution of the bush‐dwelling snail Theba pisana (Helicidae) in Israel is restricted to the coastal plain. It is known as an annual semelparous species, but recent studies revealed that part of the population has a biennial life cycle.The present study examined the water economy and resistance to desiccation throughout the life cycle under natural conditions in the field, and by exposing samples of various size (age) groups to three weeks of laboratory desiccation during various seasons.We found that resistance to desiccation in Theba pisana is age‐dependent as young snails lost more water than adults during desiccation. In general, high rates of water loss during desiccation were noted in growing snails during winter and spring, and low rates were recorded during the summer aestivation in all age groups. A small part of the natural population ceased growing and entered an early aestivation, thereby avoiding the otherwise high rates of water loss.We conclude that resistance to desiccation is entrained in the annual life cycle of T. pisana and that survival under natural desiccating conditions depends on the maturation, and on the ontogenetic development of the water preserving mechanisms. The age‐dependent water economy of the snail dictates the timing of aestivation and the establishment of a new set‐point which is reflected in the clustering behaviour, secretion of a calcareous epiphragm, and a selective compartmentalization of body fluids.
Foraging behaviour and energetics of a nectar‐feeding bat, Leptonycteris curasoae (Chiroptera: Phyllostomidae)
Authors: Horner M. A. , Fleming T. H. , Sahey C. T. 
Published: February 2006

AbstractWe studied the foraging behaviour and energetics of the nectar‐feeding bat, Leptonycteris curasoae (=L. sanborni), in the Sonoran Desert near Bahia Kino, Sonora, Mexico, using radio‐telemetry, light‐tagging, and focal plant observations to answer three questions: (1) How far do these bats fly in a night and at what energetic cost? (2) How do they harvest nectar and pollen from columnar cacti that offer large but temporally variable nectar rewards? (3) What are the implications of their foraging behaviour for gene flow within populations of their food plants?L. curasoae visited flowers of three species of columnar cacti in April through June. Many bats roosted on Isla Tiburon 20 km from the Mexican mainland and commuted about 30 km to the mainland to feed. Bats flew for about 5 h each night for a total distance of about 100 km. Individuals foraged alone or in small groups in overlapping areas of 1‐3 km2; and visited the same feeding areas on successive nights. Within feeding areas, bats visited the flowers of many cactus plants, visited most flowers <5 times, and removed about 0.1 mL of nectar per visit. Although bats flew nearly continuously early in the evening, they did most of their feeding between 24:00 and 02:00. When visiting flowers of Pachycereus pringlei (cardon), bats apparently waited until flowers had accumulated 0.8 mL of nectar before feeding, which suggests that rates of nectar secretion influence the timing of feeding in these bats. We estimate that the daily energy budget of L. curasoae is at least 40 kJ and that bats make about 80‐100 visits to cactus flowers to acquire this energy. Foraging areas typically contain thousands of cactus flowers, and thus food does not appear to be a limited resource for these bats during the spring. The cost‐efficient flight of this bat makes it an excellent pollen vector for self‐incompatible, widely spaced desert cacti.
Variation in size at birth and post‐natal growth in the insectivorous bat Pipistrellus subflavus (Chiroptera: Vespertilionidae)
Authors: Hoying K. M. , Kunz T. H. 
Published: February 2006

AbstractWe describe the size and developmental state at birth, examine factors which influence intra‐ and inter‐year variation in post‐natal growth, and derive age‐predictive equations and logistic growth parameters for the eastern pipistrelle bat, Pipistrellus subflavus. Ambient and roost temperature and insect abundance were lowest, and precipitation highest, before and during the post‐natal growth period in 1982, as compared to 1981. We found no sex differences in the size of pups at birth or in post‐natal growth rates in a given year; however, body mass and length of forearm of neonates differed significantly between years, being smaller in 1982 than in 1981. During the first two weeks of post‐natal growth in both years, the body mass and length of forearm of pups increased linearly at mean rates of 0.15 g.day−1 and 1.12 mm.day−1, respectively. Post‐natal growth rates for length of forearm and body mass were the same during the early linear phase of growth, but the intercept for body mass was less and growth trajectories were more variable in 1982. Length of forearm was the least variable and thus most reliable character for estimating age of P. subflavus pups during the first 14 days of post‐natal growth. When length of forearm was used in combination with mean changes in the length of the fourth metacarpal‐phalangeal epiphyseal gap, we derived reliable age‐estimation equations ranging from 1 to 45 days. Litter size averaged 1.96 and 1.93 at birth, but this was reduced to one by the time pups became volant. At birth, litter mass represented 44, and 54% of the post‐partum mass of females in 1981 and 1982, respectively. This maternal effort during pregnancy is among the highest reported for bats. At weaning, the body mass of pups approached 80% of adult post‐partum body mass, and the length of forearm exceeded 90% of adult female size. Our results suggest that size at birth and post‐natal growth are influenced by ambient and roost temperature, rainfall, and the quantity of insects available to pregnant and lactating females. Thus, energetic constraints on both mothers and pups can lead to inter‐year and inter‐individual differences in maternal effort and post‐natal growth of pups.
A new species of giant gecko of the genus Tarentola (Reptilia: Squamata: Gekkonidae) from Jamaica
Authors: Sprackland R. G. , Swinney G. N. 
Published: February 2006

AbstractA new species of gecko of the genus Tarentola is described from a single specimen in the herpetological collection of the National Museums of Scotland. The gecko was part of a presentation made in 1884 by a resident of Jamaica, and is presumed to be a Jamaican endemic, possibly now extinct. Though clearly a member of the predominantly African genus Tarentola, the new species bears no specific affinity with the only other known New World species, and is very distinct in lepidosis from similar African taxa. A complete description is given for this new species, and it is named Tarentola albertschwartzi. Its possible relationship to the fossil Aristelliger titan Hecht, 1951, is discussed.
Habitat selection by five ottersLutra lutrain rivers of northern Scotland
Authors: Durbin Leon S. 
Published: February 2006

AbstractUnderstanding the effects of habitat structure on otter (Lutra lutra) movements is critical to conservation management, but such information is scarce for riverine habitats where the species is most vulnerable. Between 1987 and 1990 the patterns of habitat use by five otters from river catchments in north‐east Scotland were examined by using radio‐telemetry. The main habitat variables analysed were channel width, substrate size, riparian vegetation, proximity to roads and buildings, and the coverage of surrounding vegetation and land use. All of the otters spent more of their time in relatively wide sections of river or stream, with high boulder cover and many riparian trees. However, when use was calculated as the time spent per unit area of water, narrow, gravelly streams were selected by most animals. Some of the habitat features traditionally thought to influence otter movements (e.g. riparian vegetation, land use) did not show the predicted effects. The conservation implications of these observations are discussed.
Fallow deer (Dama dama) winter defecation rate in a Mediterranean area
Authors: Massei G. , Genov P. V. 
Published: February 2006

AbstractThis study investigated the winter daily defecation rate (DDR) of fallow deer in a Mediterranean area, and reviewed the existing literature on the defecation rate of this species. A mean number of 26.5 pellet groups deer−1 day−1 was found in this study. This value was similar to that found in studies carried out in winter in the U.K. and Germany, suggesting that different diets and habitats do not affect fallow deer DDR.
Dietary response of the Eurasian badger,Meles meles, to a decline of its main prey in the Doñana National Park
Authors: Fedriani J. M. , Ferreras P. , Delibes M. 
Published: February 2006

AbstractThe Eurasian badger (Meles meles) is considered to be a harvester rather than a hunter (Kruuk, 1989), because its food usually consists of vegetables and small and easily captured animals, such as worms and insects, and it rarely captures mammals (Neal, 1986). However, in the Doñana National Park of Mediterranean Spain the badger apparently behaves as a facultative specialist in the consumption of young rabbits,Oryctolagus cuniculus(Martín, Rodríguez & Delibes, 1995). In 1990, an outbreak of Rabbit Haemorrhagic Disease (RHD) caused high mortality among adult rabbits in most of the Doñana area (Villafuerteet al., 1994), although all sites of Doñana were not affected to the same extent. This situation offered the possibility of comparing the food habits of badgers in the Doñana Biological Reserve (DBR) before (data of Martínet al., 1995) and after the outbreak of RHD, while using another site where rabbit density has changed little over the last few years as a control area.
Diet of two species of mink in Estonia: displacement of Mustela lutreola by M. vison
Authors: Maran T. , Kruuk H. , Macdonald D. W. , Polma M. 
Published: February 2006

AbstractDuring a period in the 1980s when both European mink Mustela lutreola and American mink M. vison were present in Estonia, their food was significantly different. European mink ate a greater proportion of fish and crustaceans, whereas American mink took relatively more mammals and frogs. This was probably related to a difference in habitat selection. After the disappearance of the European mink, the diet of the American mink in our main study area was similar to that of the European in the same area previously. Two alternative hypotheses are presented for the mechanisms which led to the replacement of European mink by the American species: (i) the two species have a different niche, and the American mink could replace the European mink after the latter had disappeared for unrelated reasons, or (ii) the American mink aggressively ousted the European mink, a process starting in the American mink's preferred habitat (slow flowing rivers). At present there are insufficient data to reject either of these scenarios.
Body mass dynamics in the Mediterranean pine vole Microtus duodecimcostatus
Authors: Paradis Emmanuel , Wang Xiaoming , Guédon Gérald , Croset Henri 
Published: February 2006

AbstractThe occurrence of large individuals in fluctuating populations of microtine rodents (the Chitty effect) has received considerable attention. Recent studies showed that there are no causal relationships between the Chitty effect and the multi‐annual population cycles of voles and lemmings. We studied five populations of Microtus duodecimcostatus in southern France with capture‐recapture methods. Mean body mass was constant in all populations. Maximum observed body mass was more variable, and slightly positively correlated with density, except in the most fluctuating population where the correlation was strong. A careful study of the occurrence of large voles in these populations showed that most were pregnant females, and that the few large males were present when density was high and sample sizes were large. Comparison with published studies indicates that the Chitty effect, though not restricted to microtines, is not a general phenomenon in small mammal populations. Our field results and laboratory data on the same species suggest that M. duodecimcostatus has a determinate body growth, contrary to some Microtus species which have an indeterminate growth.
Nathusius' pipistrelle bats (Pipistrellus nathusii, Keyserling & Blasius 1839) breeding in Ireland
Authors: Russ J. M. , O'Neill J. K. , Montgomery W. I. 
Published: February 2006

AbstractWe describe the most westerly known maternity colony of Nathusius' pipistrelle bats (Pipistrellus nathusii). The bats were identified by using morphometric measurements and analysis of time‐expanded echolocation and social calls. The roost, containing approximately 150 individuals, was located in a mid 19th century farm stable block and store house situated in parkland in County Antrim, Northern Ireland. The roost was visited on 30 April, 1 May and 22 June 1997. Over this period, 11 bats were caught: one adult male, five pregnant females, four lactating females and a juvenile male. Direct observation of behaviour patterns suggests that mating groups of P. nathusii may occur in Ireland as late as May. The migratory nature of this species is discussed.
Scent‐marking and territorial behaviour of Ethiopian wolves Canis simensis
Authors: Sillero‐Zubiri Claudio , Macdonald David W. 
Published: February 2006

AbstractScent‐marking behaviour and inter‐pack aggression were studied in wild Ethiopian wolf, Canis simensis, packs. Raised‐leg urinations, followed by ground scratching, were the most frequently deposited scent‐mark. Scent‐marking rates were highest along or near territory boundaries, where distances between scent‐marking sites were reduced and the proportion of multiple marks was increased, relative to other areas. Marking rates increased with wolf numbers during patrols but not during other activities. Although all adult members of a pack contributed to scent‐marking, the dominant pair marked most frequently. Subadult males scent‐marked occasionally but subadult females never did. Wolves vigorously over‐marked neighbours' scent‐marks. Most direct encounters between neighbouring wolves at territory borders were aggressive and involved repeated chases, and the larger group was most likely to win. Resident wolves were more tolerant of opposite‐sex than same‐sex neighbours. Resident wolves therefore signalled pack composition and status at home range borders by olfactory and auditory cues and by aggressive contests. Such signalling may reduce the occurrence of potentially costly inter‐pack aggressive encounters at territory borders and provide information on reproductive status.
Blood supply to the eyes and brain of lamniform sharks (Lamniformes)
Authors: Alexander R. L. 
Published: February 2006

AbstractThe arterial supply to the eyes and brain of the common thresher shark, Alopias vulpinus, was examined and compared with that of five other lamniform shark species. Temperatures of the eyes and brain in two of these species were shown in previous studies to be higher than ambient. This was considered to be correlated with the presence of an orbital rete mirabile derived from the hyoidean efferent and pseudobranchial arteries. This study shows that the pseudobranchial artery forms a rete in only one of the two species previously shown to be warm, indicating that the brain of the other species is warmed by a non‐retial vessel. This finding raises the possibility of brain and eye warming in Alopias vulpinus, which lacks an orbital rete mirabile.
Inter‐ and intraspecific variation in the post‐natal skull of some lacertid lizards
Authors: Barahona Fabiola , Barbadillo Luis Javier 
Published: February 2006

AbstractIntra‐ and interspecific variation are analysed for the post‐natal skull of the lacertid lizards Gallotia galloti, Acanthodactylus erythrurus, Algyroides marchi, Lacerta monticola, Lacerta vivipara, Podarcis bocagei, Podarcis hispanica, Podarcis muralis, Psammodromus algirus and Psammodromus hispanicus. Individual variations identified include: the presence/absence, number and morphology of some structures, mainly in the lacrimal, sclerotic ossicles and maxilla; the number and location of foramina and the degree of ossification of some processes in chondrocranial bones. No differences have been found between the sexes with respect to presence and morphology of the bones but some species show sexual dimorphism in the size and robustness of the head and this may be reflected in the individual. The most substantial variations seen are ontogenetic: the appearance of new traits; development of articulations; differences between species in the timing of the stages of development of a given structure; changes in the relative position of some cranial elements; and the degree of calcification or ossification of processes. A total of 63 characters showing interspecific variations are identified. Some have not previously been described while others used in previous studies are redefined here on the basis of new morphological information obtained.