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Since 1994 Denver Zoological Gardens has evaluated the growth and development of 13 captive‐born Polar bear Ursus maritimus cubs. In the wild ♀♀ fast while they are in the den; however, at Denver Zoological Gardens food was available all year round and the ♀♀ ate, urinated and defecated in the den, fouling it with a strong ammonia smell. Concerns for the developing cubs meant that the mothers were periodically separated from the cubs in order to clean the den. This provided the opportunity to examine and weigh the cubs until they were 12 weeks old. Additional body‐mass data were collected from other zoological institutions either through personal communications or from the literature. Infrared camera, 24 hour videotaping and audio surveillance also provided unique insights into the Polar bear maternity den.

We postulated that dietary ingestion of vitamin D may be used by some Alaskan Arctic marine mammal species in addition to, or instead of, cutaneous production to meet nutritional requirements. Zooplankton (n ¼ 5) sampled near Kaktovik, Alaska, contained no measurable vitamin D 2 or D 3 , but did contain provitamin D (7-dehydrocholesterol), the cutaneous precursor for previtamin D 3 in mammals. Fillets and livers from five fish species were sampled near Barrow, Alaska, and evaluated for vitamin D 3 content (no vitamin D 2 was detected). Differences in vitamin D 3 content appeared significant (Pr0.10) among fish livers (KruskalWallis [H test] ¼ 8.25, df ¼ 4, P ¼ 0.08) and among fish fillets (H ¼ 7.80, df ¼ 4, P ¼ 0.01). We also found significant differences in several pairwise comparisons (Mann-Whitney U-test) of vitamin D 3 levels in fillets and livers. Blubber from six species of marine mammals had no detectable vitamin D 2 . The H test results for blubber vitamin D 3 concentration were highly significant: 28.12, df ¼ 5, Po0.001. There were also significant differences in vitamin D 3 content from blubber in pairwise comparisons of primarily invertebrate feeders (bowhead whale (Balaena

We examined variables that might affect survivorship of neonatal argali sheep (Ovis ammon), including body weight, date of birth, gender, precipitation, and year affects, which often influence neonatal survivorship in other species of sheep. From 2003 to 2008 we handcaptured 75 argali lambs (38(, 36&, 1 undetermined) and attached expandable, drop-off radio collars in Ikh Nart Nature Reserve, Mongolia. We collected morphometric and physiological measurements and radiotracked lambs to obtain data on survivorship and mortality. We found similar morphometric and physiological measurements for male and female lambs, with significant differences only in foreleg length (&-() and respiration rates (&)(). Only 44.6% of argali lambs survive their first month of life, but thereafter their mortality rate decreases. Lambs not born in 2006, born in years following years with higher April precipitation, and born later in the year enjoyed significantly higher survival to one month. We found high mortality in the years with severe drought (2005)(2006), which depressed overall survivorship. We found no significant effect of any physiological or morphometric variables on lamb survival. Argali lambs die from several causes, with predation (44.6%) and starvation (21.4%) being the most significant.

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The difference between serum levels from 36 captive and 56 free‐ranging polar bears (Ursus maritimus) for 25‐hydroxyvitamin D (25‐OH‐D) was found not to be significant (mean ± SD = 348 ± 215 nmol/L [captive], 360 ± 135 nmol/L [free‐ranging], t = 0.30, df = 52.8, P = 0.76), whereas the difference for retinol and α‐tocopherol was significant (retinol, 1.37 ± 0.67 μmol/L [captive] 1.89 ± 0.63 μmol/L [free‐ranging], t = 3.88, df = 72.4, P <0.001, α‐tocopherol, 18.56 ± 18.56 μmol/L [captive], 48.76 ± 13.92 μmol/L [free‐ranging], t = 7.85, df = 61.9, P < 0.001). Due to the high fat content in the polar bear diet, seal blubber may be the source of these fat‐soluble vitamins. Six skin biopsies were analyzed from captive polar bears at the Denver Zoological Gardens for 7‐dehydrocholesterol levels and found to contain 0.11 ± 0.03 nmol/cm2. This finding also helps to support the contention that the source of vitamin D for polar bears may be ingestion and not cutaneous production. Vitamin D content in the milk from one captive sow in the den (0.14 nmol/g) and 10 free‐ranging sows with cubs of the year out on the ice pack (0.0042 ± 0.0073 nmol/g) were also evaluated. It would be helpful to evaluate additional milk samples from denning and non‐denning sows with cubs to see whether vitamin D content varies according to the stage of lactation. Zoo Biol 17:285–293, 1998. © 1998 Wiley‐ Liss, Inc.

Excessive maternal iron may affect female fetuses more than males, possibly inducing leukoencephalomalacia by catalyzing production of highly toxic hydroxyl free radicals during crucial periods of in utero development. Reduction of maternal iron overload may decrease the probability of developing leukoencephalomalacia and some other disorders commonly affecting rhinoceroses in captivity.

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