Vitamin D Status and Bone and Connective Tissue Turnover in Brown Bears (Ursus arctos) during Hibernation and the Active State

BACKGROUND: Extended physical inactivity causes disuse osteoporosis in humans. In contrast, brown bears (Ursus arctos) are highly immobilised for half of the year during hibernation without signs of bone loss and therefore may serve as a model for prevention of osteoporosis. AIM: To study 25-hydroxy-vitamin D (25OHD) levels and bone turnover markers in brown bears during the hibernating state in winter and during the active state in summer. We measured vitamin D subtypes (D₂ and D₃), calcitropic hormones (parathyroid hormone [PTH], 1,25-dihydroxy-vitamin D [1,25(OH)₂D]) and bone turnover parameters (osteocalcin, ICTP, CTX-I), PTH, serum calcium and PIIINP. MATERIAL AND METHODS: We drew blood from seven immobilised wild brown bears during hibernation in February and in the same bears while active in June. RESULTS: Serum 25-hydroxy-cholecalciferol (25OHD₃) was significantly higher in the summer than in the winter (22.8±4.6 vs. 8.8±2.1 nmol/l, two tailed p-2p = 0.02), whereas 25-hydroxy-ergocalciferol (25OHD₂) was higher in winter (54.2±8.3 vs. 18.7±1.7 nmol/l, 2p<0.01). Total serum calcium and PTH levels did not differ between winter and summer. Activated 1,25(OH)₂D demonstrated a statistically insignificant trend towards higher summer levels. Osteocalcin levels were higher in summer than winter, whereas other markers of bone turnover (ICTP and CTX-I) were unchanged. Serum PIIINP, which is a marker of connective tissue and to some degree muscle turnover, was significantly higher during summer than during winter. CONCLUSIONS: Dramatic changes were documented in the vitamin D₃/D₂ ratio and in markers of bone and connective tissue turnover in brown bears between hibernation and the active state. Because hibernating brown bears do not develop disuse osteoporosis, despite extensive physical inactivity we suggest that they may serve as a model for the prevention of this disease

Despotism and Risk of Infanticide Influence Grizzly Bear Den-Site Selection

Given documented social dominance and intraspecific predation in bear populations, the ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female grizzly bears (Ursus arctos) will avoid areas occupied by adult males to reduce risk of infanticide. Under ideal despotic distribution, juveniles should similarly avoid adult males to reduce predation risk. Den-site selection and use is an important component of grizzly bear ecology and may be influenced by multiple factors, including risk from conspecifics. To test the role of predation risk and the sex hypothesis of sexual segregation, we compared adult female (n = 142), adult male (n = 36), and juvenile (n = 35) den locations in Denali National Park and Preserve, Alaska, USA. We measured elevation, aspect, slope, and dominant land cover for each den site, and used maximum entropy modeling to determine which variables best predicted den sites. We identified the global model as the best-fitting model for adult female (area under curve (AUC) = 0.926) and elevation as the best predictive variable for adult male (AUC = 0.880) den sites. The model containing land cover and elevation best-predicted juvenile (AUC = 0.841) den sites. Adult females spatially segregated from adult males, with dens characterized by higher elevations ( = 1,412 m, SE = 52) and steeper slopes ( = 21.9°, SE = 1.1) than adult male (elevation:  = 1,209 m, SE = 76; slope:  = 15.6°, SE = 1.9) den sites. Juveniles used a broad range of landscape attributes but did not avoid adult male denning areas. Observed spatial segregation by adult females supports the sex hypothesis of sexual segregation and we suggest is a mechanism to reduce risk of infanticide. Den site selection of adult males is likely related to distribution of food resources during spring

Brazilian cave heritage under siege

info:eu-repo/semantics/publishe

Avifaunal records from Chalis Ek, North Andaman Island: insights into distribution of some Andaman Island birds

Species records are important for assessing the distribution and status of species over a spatiotemporal scale. Andaman archipelago, off Southeast Asia, is a high avian endemism area, covering an area of >5000 km2. We conducted this survey in 2011 to make an inventory of avifauna of Chalis Ek area. A total of 73 species, belonging to 61 genera and 34 families were recorded, of which 60 were resident, 11 were winter migrants, one vagrant, and a single species introduced from mainland India. Three species were found to be new records, expanding distribution. Thirteen were endemic to the Andaman and Nicobar group of islands and eleven were listed as near threatened in the IUCN Red List. This study shows that sites such as Chalis Ek, even though subject to moderate anthropogenic disturbance, still hosts a large and distinctive avifauna and should be protected

Avifaunal records from Chalis Ek, North Andaman Island: insights into distribution of some Andaman Island birds

Species records are important for assessing the distribution and status of species over a spatiotemporal scale. Andaman archipelago, off Southeast Asia, is a high avian endemism area, covering an area of >5000 km2. We conducted this survey in 2011 to make an inventory of avifauna of Chalis Ek area. A total of 73 species, belonging to 61 genera and 34 families were recorded, of which 60 were resident, 11 were winter migrants, one vagrant, and a single species introduced from mainland India. Three species were found to be new records, expanding distribution. Thirteen were endemic to the Andaman and Nicobar group of islands and eleven were listed as near threatened in the IUCN Red List. This study shows that sites such as Chalis Ek, even though subject to moderate anthropogenic disturbance, still hosts a large and distinctive avifauna and should be protected

Roosting patterns of the Edible-Nest Swiftlet (<i>Aerodramus fuciphagus</i>) of the Andaman Islands: effects of lunar phase and breeding chronology

<p>Environmental conditions and biological rhythms can affect the behavioural routines of animals. However, the effect of lunar phase on individual roosting behaviour remains uninvestigated in most species. Here, we monitored the effect of lunar phase, sunset time, temperature, humidity and the breeding chronology on the roosting patterns of the Edible-Nest Swiftlet (<i>Aerodramus fuciphagus</i>) of the Andaman Islands, across breeding stages. Counts revealed that more than 98% of the population returned to the roosting caves during peak roosting hours, i.e. 1700–2000h. The proportion of birds roosting in caves was highest during the ‘new moon’ phase and when birds were at the nest-building and fledging stage of their breeding cycle. We confirmed that the variation in the roosting behaviour of the Edible-Nest Swiftlet is linked both to the stages in the breeding cycle and to the lunar phase. We hypothesise that the cause for the lunarphilic roosting pattern is an anti-predator strategy. Feeding habits and food requirements during different breeding stages are presumed to influence the roosting pattern of the species. An improved understanding of the association of the behaviour, physiology and the environmental conditions which influence these traits can only help us improve conservation outcomes for this economically important species.</p

Asians as the model minority: Implications for US Government's policies

Asian Americans are often perceived as a `model minority' - an ethnic minority that are high achieving, hardworking, self-reliant, law-abiding, as well as having few social and mental health problems. Although the impact of the model minority image on the US government's redistributive policies is a widely contested topic in public discourses, there has been little research on the association between the model minority image, people's worldviews, and attitudes towards the US government's redistributive policies. In an experiment that measured American participants' worldviews and manipulated the salience of the model minority image, we have demonstrated that those who believed in a malleable social reality were relatively unsupportive of government policies that help the Asian American (vs African American) communities. Theoretical and practical implications of this finding are discussed