Zoos have too many endangered male animals

Zoos are too male-centric when it comes to the sex ratio of some of their endangered animals, according to an analysis of birth records, and that could be a problem for conservation. A study published in Scientific Reports of 2.6 million zoo birth records for 450 different species revealed that there were more males than females of some species, including endangered ones like Asian elephants (Elephas maximus). The reasons for these sex ratio biases are varied and depend on the species. But in animals that are endangered—and especially in those used for captive breeding programs—it could cause problems with inbreeding and even housing, where conflicts occur between same-sex individuals. “Our findings show that even well-managed zoos may be silently accumulating sex biases that threaten the survival of endangered species,” said Oscar Miranda, the first author of the study and a researcher at the University of Debrecen in Hungary, in a press release.

Read more at the University of Bath.