Milk production in males has never before been reported in wild animals. Thus far, it has been seen only in some highly inbred domestic animals and human males with tumors, those undergoing hormone treatments, or babies at birth. Even in these instances, it is extremely rare. In the case of Dayak fruit bats, the males have the correct plumbing and physiological capability to lactate, but the scientists don't yet know what it means. Although the males produced milk, their mammary glands and nipples were not as large as females, and the amount of milk was only about a tenth of that produced by females. Males were not observed nursing young.

Data Sources: Mace, G.M. and Balmford, A. 2000. Patterns and processes in contemporary mammalian extinction. In: A. Entwhistle and N. Dunstone (eds) Future priorities for the conservation of mammalian diversity. Cambridge University Press, Cambridge.

Photograph Information: Courtesy of Lubee Collection