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In primates, the primary source of vitamin D is synthesis in the skin through sun exposure. Decreased sun exposure may lead to vitamin D deficiency and consequently other health issues. In laboratory, sanctuary, and zoo settings, chimpanzees (Pan troglodytes) may be housed indoors for prolonged periods of time without regular exposure to unfiltered sunlight. However, little research has examined the relationship between housing conditions and vitamin D serum levels in captive chimpanzees. In this study, we retrospectively compared serum levels of total vitamin D, calcium, ionic calcium, phosphorous, albumin, and alkaline phosphatase in 18 female and 12 male chimpanzees as they cycled between indoor-only and indoor-outdoor enclosures. Total vitamin D was significantly lower and alkaline phosphatase significantly higher when subjects were in the indoor-only enclosures compared with when they had regular access to outdoor enclosures. A vitamin D effect occurred only in young and prime-adult animals. Changes were significant in female but not in male chimpanzees. Calcium, ionic calcium, phosphorus, and albumin did not differ between indoor-only and indoor-outdoor enclosures. However, female chimpanzees exhibited significantly lower calcium and phosphorous levels while in the indoor-only enclosures. These results suggest that adult captive chimpanzees experience vitamin D deficiency when housed without regular access to unfiltered sunlight and that these effects may be more acute for adult female animals.

In the wild, great apes sleep in beds they make by successively bending branches into an interwoven platform. These beds are functionally more closely related to human beds than they are to the nests and tree-holes used by other primate species. The idea that bed-building by great apes is learned behavior that is dependent on appropriate early experiences has been proposed but never fully tested. In the present study this hypothesis was indirectly tested in 73 captive adult chimpanzees (Pan troglodytes; 27 wild-born and 46 captive-born). Bed-building and use were tested experimentally by the introduction of three sets of bedding materials. Over 200 hr of scan-sampling data were collected during 45-min observations following introduction of the bedding material. The wild-born subjects built and used beds significantly more often than the captive-born subjects. Also, wild-born subjects used more complex techniques during construction. Captive-born subjects that were mother-reared through early adolescence spent more time building and using beds than their nursery-reared counterparts. These differences remained consistent even when previous adult experience with bedding (measured as naturalistic vs. traditional housing) was accounted for. These results suggest that bed-building is a learned behavior that requires early experience and practice for acquisition., ((c) 2005 Wiley-Liss, Inc.)