Dry Season Diet of the Sloth Bear (Melursus ursinus) in Hadagarh Wildlife Sanctuary,Eastern India

Dry season food habit of sloth bear (Melursus ursinus) in Hadagarh Wildlife Sanctuary was characterized by scat analysis. Importance value index (IVI) of contribution of different food items in the diet of sloth bear was estimated from the undigested food remnants. Percentage of dry weight and IVI score of Ziziphus fruits was highest, termites were the most frequently occurring food item in the diet and percentage of frequency occurrence was equal for both fruits and insects. The present study, as compared to previous studies, suggests that the dietary preference of sloth bear varies according to availability of food and the habitat quality.     

Seed Dispersal by the Sloth Bear (Melursus ursinus) in South India1

Previous studies have shown that sloth bears are mainly myrmecophagous, but in this study, 39 and 83 percent (wet and dry season, respectively) of scats surveyed in South India contained fruits. Seeds from three of six plant species collected from scats germinated faster than seeds not passing through bears; germination percentage was not higher in any of the six species. These results suggest that the sloth bear may play an important role in the population dynamics of fleshy‐fruited species of the region.     

Habitat occupancy of sloth bear Melursus ursinus in Chitwan National Park,Nepal

Mammals have experienced a massive decline in their populations and geographic ranges worldwide. The sloth bear, Melursus ursinus (Shaw, 1791), is one of many species facing conservation threats. Despite being endangered in Nepal, decades of inattention to the situation have hindered their conservation and management. We assessed the distribution and patterns of habitat use by sloth bears in Chitwan National Park (CNP), Nepal. We conducted sign surveys from March to June, 2020, in 4 × 4 km grids (n = 45). We collected detection/non‐detection data along a 4‐km trail that was divided into 20 continuous segments of 200 m each. We obtained environmental, ecological, and anthropogenic covariates to understand determinants of sloth bear habitat occupancy. The data were analyzed using the single‐species single‐season occupancy method, with a spatially correlated detection. Using repeated observations, these models accounted for the imperfect detectability of the species to provide robust estimates of habitat occupancy. The model‐averaged occupancy estimate for the sloth bear was 69% and the detection probability was 0.25. The probability of habitat occupancy by sloth bears increased with the presence of termites and fruits and in rugged, dry, open, undisturbed habitats. Our results indicate that the sloth bear is elusive, functionally unique, and widespread in CNP. Future conservation interventions and action plans aimed at sloth bear management must adequately consider their habitat requirements.     

Hematology of sloth bears (Melursus ursinus ursinus) from two locations in India

Standard hematology parameters were determined for 122 sloth bears (Melursus ursinus ursinus) at the Sur Sarovar Bird Sanctuary, Uttar Pradesh, India (27 degrees 0'N; 77 degrees 45'E), and the Bannerghatta Biological Park, Karnataka, India (12 degrees 48'N; 77 degrees 34'E) from March 2003 to July 2006. These two native sloth bear habitats have different climatic conditions and provided an opportunity to examine the effect of climate on the physiologic hematology values of these bears. We primarily analyzed the influence of age, sex, season, and body weight on the different hematology parameters. Several values were significantly different in sloth bear cubs (1 yr). The cubs had a lower erythrocyte count, hemoglobin concentration, packed cell volume (PCV), and mean cell hemoglobin (MCV) values when compared to adult and subadult bears. The cubs also had higher leukocyte counts, due to higher circulating neutrophils, as compared to adult and subadult bears. Within subadult and adult bears, we also identified a sexual dimorphic difference in leukocyte count in adult and subadult bears, wherein female bears had higher counts than males. This difference was the result of a significantly higher number of circulating neutrophils in female bears. Platelet counts were also higher in females as compared to males. On comparing different seasons, leukocyte counts were higher in winter as compared to the summer and monsoon seasons. When compared based on location, erythrocyte counts were higher in subadult and adult bears at Bannerghatta, which was at a higher altitude than Sur Sarovar. Within subadult and adult bears, we did not find any significant influence of age or body weight on the different hematologic parameters. In this study we have obtained mean hematologic values for sloth bears in their native habitat to serve as a reference for this species. This report will be useful to develop and evaluate health profiles of sloth bears under various ecological conditions.     

Genetic Variation,Structure, and Gene Flow in a Sloth Bear (Melursus ursinus) Meta-Population in the Satpura-Maikal Landscape of Central India

Sloth bears (Melursus ursinus) are endemic to the Indian subcontinent. As a result of continued habitat loss and degradation over the past century, sloth bear populations have been in steady decline and now exist only in isolated or fragmented habitat across the entire range. We investigated the genetic connectivity of the sloth bear meta-population in five tiger reserves in the Satpura-Maikal landscape of central India. We used noninvasively collected fecal and hair samples to obtain genotypic information using a panel of seven polymorphic loci. Out of 194 field collected samples, we identified 55 individuals in this meta-population. We found that this meta-population has moderate genetic variation, and is subdivided into two genetic clusters. Further, we identified five first-generation migrants and signatures of contemporary gene flow. We found evidence of sloth bears in the corridor between the Kanha and Pench Tiger Reserves, and our results suggest that habitat connectivity and corridors play an important role in maintaining gene flow in this meta-population. These corridors face several anthropogenic and infrastructure development threats that have the potential to sever ongoing gene flow, if policies to protect them are not put into action immediately.     

Behavioural ecology of the Greater one-horned rhinoceros (Rhinoceros unicornis)

In the Chitawan Valley of Nepal there were estimated to be between 270 and 310 Greater one-horned or Indian rhinoceroses (Rhinoceros unicornis L.). Population densities reached 4.85 rhinos/km² in the favoured areas of high diversity of early successional vegetation types on the valley floor. The overall population composition was 32.3% adult females, 19.9% adult males, 21.2% sub-adults and 26.6% calves. Females first calved at a mean age of 7.1 years and the median intercalving interval was 2.8 years. Causes of death included poaching, tiger predation on calves and fighting among males. The population was increasing.
Rhinos fed from 183 species of plants belonging to 57 botanical families but grass (50 species) made up between 70 and 89% of their diet according to the season. Considerable seasonal variations in food availability resulted in movements of rhinos between vegetation types. Rhinos' ranges were smallest in the areas of greatest vegetational diversity.
Rhinos rarely formed groups. The most common type consisted of sub-adults–mainly males. Ten auditory displays were distinguished and visual displays, although less striking, included baring the lower incisor tusks. Scents were carried in the dung, the urine and the pedal scent glands. Squirt urination and foot-dragging displays were performed by breeding males only.
There was some degree of range exclusivity among breeding males but no true territoriality. Poor visibility and the relatively unpredictable distribution of resources in time and space have perhaps selected against a territorial mating system. Relationships between ecology and social organization are discussed with reference to other rhino species.
Threats to the continued survival of the Indian rhino include poaching, agricultural encroachment and erosion. In order to spread the risk of a catastrophe, reintroductions of rhinos to other protected areas are proposed.     

Behavioural ecology of the black mongoose (Galerella nigrata) in Namibia

The black mongoose (Galerella nigrata) occurs in northern Namibia, where it occupies habitats dominated by large boulders (petrophily). Because of its restricted distribution, virtually nothing has been documented about its natural history. To fill this data gap, six males were radio-tracked in the foothills of the Erongo Mountains, Namibia in 2003. Although largely solitary, some home ranges overlapped nearly 100%. Males sometimes formed hunting diads similar to other congeners. The animals were diurnal and denned alone, using multiple sites haphazardly from night to night. The diet included many petrophilic vertebrates. The taxonomic status of the black mongoose is controversial; in addition to morphological evidence that it is a full species, it appears to be a habitat specialist compared with other forms of Galerella in southern African.     

Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus)

In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.     

Comparative Phylogeography of the Atlantic Forest Endemic Sloth (Bradypus torquatus) and the Widespread Three-toed Sloth (Bradypus variegatus) (Bradypodidae, Xenarthra)

The comparative phylogeographic study of the maned sloth (Bradypus torquatus) and the three-toed sloth (Bradypus variegatus) was performed using a segment of mitochondrial DNA (mtDNA) control region. We examined 19 B. torquatus from two regions and 47 B. variegatus from three distant regions of Atlantic forest. This first characterization of molecular diversity indicates a great diversity (B. torquatus: h = 0.901 ± 0.039 and π = 0.012 ± 0.007; B. variegatus: h = 0.699 ± 0.039 and π = 0.010 ± 0.006) and very divergent mitochondrial lineages within each sloth species. The different sampled regions carry distinct and non-overlapping sets of mtDNA haplotypes and are genetically divergent. This phylogeographic pattern may be characteristic of sloth species. In addition, we infer that two main phylogeographic groups exist in the Atlantic forest representing a north and south distinct divergence.     

灰喜鹊的行为生态学研究 Ⅰ．生殖行为

在从南到北的地理分布上,灰喜鹊的繁殖期相应有所推迟．在它们的繁殖区域,人类的影响越大,其巢也建得越高、越隐蔽．这种很强的适应性使得它们在城区和近郊区能够更好地生存和繁殖．北京地区的灰喜鹊在４月中、下旬开始建巢,５月底是产卵高峰期．在孵卵期它们不断地翻动卵,以使其受热均匀．灰喜鹊对卵的数量比对卵的颜色和大小更敏感．孵卵期约１５—１７天,幼鸟１８—２０天出巢．在北京大学校园内的灰喜鹊的繁殖成功率约为６９．０５％．建立了灰喜鹊的发育行为谱．在繁殖期,灰喜鹊的巢彼此靠得较近,形成一个集体生殖领域,共同进行集体防御．     

灰喜鹊的行为生态学研究Ⅰ．生殖行为

在从南到北的地理分布上,灰喜鹊的繁殖期相应有所推迟。在它们的繁殖区域,人类的影响越大,其巢也建得越高、越隐蔽。这种很强的适应性使得它们在城区和近郊区能够更好地生存和繁殖。北京地区的灰喜鹊在4月中、下旬开始建巢,5月底是产卵高峰期。在孵卵期它们不断地翻动卵,以使其受热均匀。灰喜鹊对卵的数量比对卵的颜色和大小更敏感。孵卵期约15-17天,幼鸟18-20天出巢。在北京大学校园内的灰喜鹊的繁殖成功率约为69.05%.建立了灰喜鹊的发育行为谱。在繁殖期,灰喜鹊的巢彼此靠得较近,形成一个集体生殖领域,共同进行集体防御。     

Behavioural ecology: hidden benefits revealed

In the cooperatively breeding superb fairy-wren, helpers have negligible effect on breeding success. So why help? The answer is hidden in the size of the eggs.     

Architectural Properties of Sloth Forelimb Muscles (Pilosa: Bradypodidae)

Tree sloths have reduced skeletal muscle mass, and yet they are able to perform suspensory behaviors that require both strength and fatigue resistance to suspend their body mass for extended periods of time. The muscle architecture of sloths is hypothesized to be modified in ways that will enhance force production to compensate for this reduction in limb muscle mass. Our objective is to test this hypothesis by quantifying architecture properties in the forelimb musculature of the brown-throated three-toed sloth (Bradypus variegatus: N = 4). We evaluated architecture from 52 forelimb muscles by measuring muscle moment arm (r _m), muscle mass (MM), belly length (ML), fascicle length (L_F), pennation angle (θ), and physiological cross-sectional area (PCSA), and these metrics were used to estimate isometric force, joint torque, and power. Overall, the musculature becomes progressively more pennate from the extrinsic to intrinsic regions of the forelimb, and the flexors are more well developed than the extensors as predicted. However, most muscles are indicative of a mechanical design for fast joint rotational velocity instead of large joint torque (i.e., strength), although certain large, parallel-fibered shoulder (e.g., m. latissimus dorsi) and elbow (e.g., m. brachioradialis) flexors are capable of producing appreciable torques by having elongated moment arms. This type of functional tradeoff between joint rotational velocity and mechanical advantage is further exemplified by muscle gearing in Bradypus that pairs synergistic muscles with opposing L_F/r _m ratios in each functional group. These properties are suggested to facilitate the slow, controlled movements in sloths. In addition, the carpal/digital flexors have variable architectural properties, but their collective PCSA and joint torque indicates the capability for maintaining grip force and carpal stability while distributing load from the manus to the shoulder. The observed specializations provide a basis for understanding sustained suspension in sloths.     

Behavioural ecology: social networking for dullards

A recent paper shows that dull-plumaged male house finches can improve their mating success by moving to a different social network, where their plumage is brighter relative to that of other males.     

Intertroop relations of chacma baboon (Papio ursinus)

Intertroop relations among four troops of the chacma baboon population on the Suikerbosrand Nature Reserve, southern Transvaal, South Africa, were studied for 18 months using radiotelemetry. Encounters between troops occurred only rarely and were relatively nonantagonistic in character. Dominance among the four troops was difficult to identify by means of behavior although differences in range quality among the four were marked. The way in which intertroop relations affected the fitness of members of each of the troops was, therefore, unclear. Transfer of individuals from one troop to another was easily accomplished by both males and females and probably negated the effects of differential range quality on individual reproductive fitness.