Temporal and individual variation in the feeding habits of Asiatic black bears (Ursus thibetanus).

Foraging plays a vital role in the survival of wildlife, and shifts in food availability can impact species fitness and survival. Ursids are known to consume a wide variety of foods and are known to be opportunistic omnivores. Consequently, seasonal shifts in diet, which correspond to temporal and spatial shifts in the availability of food resources, have long captivated researchers studying the foraging behavior of Ursidae. Nevertheless, comprehensive dietary studies encompassing both the population and individual levels remain scarce. In this study, we investigated the dietary patterns of Asiatic black bears (Ursus thibetanus) at both the population and individual levels, using data collected through GPS collars and field surveys of individual bear scat samples in Nagano Prefecture, Japan, from 2016 to 2020. From early April to late June, bears mainly foraged on green vegetation. During this period, male and large-bodied female bears showed a strong preference for green vegetation. Small-bodied female bears also ate mostly green vegetation but tended to consume more fruit than other bears towards the end of this period. From June to October, bears' diets included a substantial amount of fruit, with notable peaks in fruit consumption in late June and early September. During the summer months, female bears often incorporated social insects into their diet compared to the population-level trend. In mid-September, the consumption of seeds from the Fagaceae family surged, becoming the primary dietary component during this period. This trend was consistently observed across the population. These findings underscore the importance conducting in-depth dietary analyses that take into account individual characteristics such as sex, age, and body weight.

Applying a Random Encounter Model to Estimate the Asiatic Black Bear (Ursus thibetanus) Density from Camera Traps in the Hindu Raj Mountains, Pakistan.

Estimating the population density of vulnerable species, such as the elusive and nocturnal Asiatic black bear (Ursus thibetanus), is essential for wildlife conservation and management. We used camera traps and a Random Encounter Model (REM) to estimate the population density of U. thibetanus during the autumn and winter seasons in the Hindu Raj Mountains. We installed 23 camera traps from October to December 2020 and acquired 66 independent pictures of Asiatic black bears over 428 trap nights. Our results showed that the bears preferred lowland areas with the presence of Quercus spp. We estimated, using the REM, a population density of U. thibetanus of 1.875 (standard error = 0.185) per square kilometer, which is significantly higher than that in other habitats. Our results showed that during autumn and winter, the bear population density tends to concentrate at lower elevations. Forest cover showed a positive correlation with the rates of bear encounters unlike the Euclidean distance to human settlements, altitude, and aspect variables. The approaches used here are cost-effective for estimating the population density of rare and vulnerable species such as U. thibetanus, and can be used to estimate their population density in Pakistan. Population density estimation can identify areas where the bears live and human-bear conflicts occurred and use this information in future wildlife management plans.

The vitamin D receptor in osteoblastic cells but not secreted parathyroid hormone is crucial for soft tissue calcification induced by the proresorptive activity of 1,25(OH)2D3.

The vitamin D receptor (VDR) is expressed most abundantly in osteoblasts and osteocytes (osteoblastic cells) in bone tissues and regulates bone resorption and calcium (Ca) and phosphate (P) homeostasis in association with parathyroid hormone (PTH). We previously reported that near-physiological doses of vitamin D compounds suppressed bone resorption through VDR in osteoblastic cells. We also found that supra-physiological doses of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] induced bone resorption and hypercalcemia via VDR in osteoblastic cells. Here, we report that the latter, a proresorptive dose of 1,25(OH)2D3, causes soft tissue calcification through VDR in osteoblastic cells. High concentrations of vitamin D affect multiple organs and cause soft tissue calcification, with increases in bone resorption and serum Ca levels. Such a variety of symptoms is known as hypervitaminosis D, which is caused by not only high doses of vitamin D but also impaired vitamin D metabolism and diseases that produce 1,25(OH)2D3 ectopically. To clarify the biological process hierarchy in hypervitaminosis D, a proresorptive dose of 1,25(OH)2D3 was administered to wild-type mice in which bone resorption had been suppressed by neutralizing anti-receptor activator of NF-κB ligand (RANKL) antibody. 1,25(OH)2D3 upregulated the serum Ca x P product, concomitantly induced calcification of the aorta, lungs, and kidneys, and downregulated serum PTH levels in control IgG-pretreated wild-type mice. Pretreatment of wild-type mice with anti-RANKL antibody did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but inhibited the increase of the serum Ca x P product and soft tissue calcification induced by 1,25(OH)2D3. Consistent with the effects of anti-RANKL antibody, VDR ablation in osteoblastic cells also did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but suppressed the 1,25(OH)2D3-induced increase of the serum Ca x P product and calcification of soft tissues. Taken together with our previous results, these findings suggest that bone resorption induced by VDR signaling in osteoblastic cells is critical for the pathogenesis of hypervitaminosis D, but PTH is not involved in hypervitaminosis D.

Effect of Sway Frequency on the Joint Angle and Center of Pressure in Voluntary Sway.

Voluntary sway is the periodic movement of one's body back and forth. The study aimed to clarify the effects of sway frequency on center of pressure and joint angle during voluntary sway. We measured 10 unrestricted voluntary sway conditions with different frequencies and natural pace conditions. The frequencies ranged from 0.1 to 1 Hz in 0.1-Hz increments. The joint angles and centers of pressure during voluntary sway were compared between the conditions. The joint angle amplitude of the trunk and knee were greater in the slow frequency condition than in the fast frequency condition. The trunk and knee joint angles during voluntary sway were considered to change according to the sway frequency.

The Vitamin D Receptor in Osteoblast-Lineage Cells Is Essential for the Proresorptive Activity of 1α,25(OH)2D3 In Vivo.

We previously reported that daily administration of a pharmacological dose of eldecalcitol, an analog of 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], increased bone mass by suppressing bone resorption. These antiresorptive effects were found to be mediated by the vitamin D receptor (VDR) in osteoblast-lineage cells. Using osteoblast-lineage-specific VDR conditional knockout (Ob-VDR-cKO) mice, we examined whether proresorptive activity induced by the high-dose 1α,25(OH)2D3 was also mediated by VDR in osteoblast-lineage cells. Administration of 1α,25(OH)2D3 (5 µg/kg body weight/day) to wild-type mice for 4 days increased the number of osteoclasts in bone and serum concentrations of C-terminal crosslinked telopeptide of type I collagen (CTX-I, a bone resorption marker). The stimulation of bone resorption was concomitant with the increase in serum calcium (Ca) and fibroblast growth factor 23 (FGF23) levels, and decrease in body weight. This suggests that a toxic dose of 1α,25(OH)2D3 can induce bone resorption and hypercalcemia. In contrast, pretreatment of wild-type mice with neutralizing anti-receptor activator of NF-κB ligand (RANKL) antibody inhibited the 1α,25(OH)2D3-induced increase of osteoclast numbers in bone, and increase of CTX-I, Ca, and FGF23 levels in serum. The pretreatment with anti-RANKL antibody also inhibited the 1α,25(OH)2D3-induced decrease in body weight. Consistent with observations in mice conditioned with anti-RANKL antibody, the high-dose administration of 1α,25(OH)2D3 to Ob-VDR-cKO mice failed to significantly increase bone osteoclast numbers, serum CTX-I, Ca, or FGF23 levels, and failed to reduce the body weight. Taken together, this study demonstrated that the proresorptive, hypercalcemic, and toxic actions of high-dose 1α,25(OH)2D3 are mediated by VDR in osteoblast-lineage cells.

Dietary specialization depending on ecological context and sexual differences in Asiatic black bears.

The food habits of the Asiatic black bear (Ursus thibetanus) are well studied, but there is a little evidence of dietary specialization-that is, when individuals use a narrower set of resources compared to the population as a whole. To examine the dietary composition at the individual level, seasonal patterns of dietary specialization, and sex-based dietary differences in Asiatic black bears, we attached Global Positioning System (GPS) collars to 15 Asiatic black bears and collected their scats in Nagano Prefecture, Japan from 2017 to 2018. Our results showed that the dietary composition differed among individuals, although seasonal changes in dietary composition were observed at the population level. Dietary specialization was high in summer (resources less abundant) and low in spring and autumn (resources more abundant), indicating a relationship with general food abundance and the dietary diversity of bears. In spring, all bears consumed green vegetation and/or seed of Fagaceae family from previous autumn; in early- and late- summer, dietary composition, such as green vegetation, insects, and fruits, greatly differed among individuals. In autumn, most bears heavily depended on seeds of Fagaceae which is high-quality food for bears. Although we did not find statistical differences between sexes in terms of dietary specialization and diversity, we found variations in the timing of feeding on the Fagaceae family, being earlier in females compared with males. We also found considerable variation in dietary composition within sexes, suggesting that dietary specialization depends on multiple factors besides food abundance, food diversity, and sex.

Representations of microgeometric tactile information during object recognition.

Object recognition through tactile perception involves two elements: the shape of the object (macrogeometric properties) and the material of the object (microgeometric properties). Here we sought to determine the characteristics of microgeometric tactile representations regarding object recognition through tactile perception. Participants were directed to recognize objects with different surface materials using either tactile information or visual information. With a quantitative analysis of the cognitive process regarding object recognition, Experiment 1 confirmed the same eight concepts (composed of rules defining distinct cognitive processes) commonly generated in both tactile and visual perceptions to accomplish the task, although an additional concept was generated during the visual task. Experiment 2 focused only on tactile perception. Three tactile objects with different surface materials (plastic, cloth and sandpaper) were used for the object recognition task. The participants answered a questionnaire regarding the process leading to their answers (which was designed based on the results obtained in Experiment 1) and to provide ratings on the vividness, familiarity and affective valence. We used these experimental data to investigate whether changes in material attributes (tactile information) change the characteristics of tactile representation. The observation showed that differences in tactile information resulted in differences in cognitive processes, vividness, familiarity and emotionality. These two experiments collectively indicated that microgeometric tactile information contributes to object recognition by recruiting various cognitive processes including episodic memory and emotion, similar to the case of object recognition by visual information.