ASA, Cheryl; Saint Louis Zoo: Recovery of Endangered Mexican Gray Wolves (Canis lupus baileyi) and Island Foxes (Urocyon littoralis)

Captive breeding can be a critical component of recovery for endangered species. The Mexican wolf, extinct in the wild, became the focus of a binational zoo-based recovery plan and has been reintroduced into part of its original range. Following population crashes from eagle predation and disease, foxes from California�s Channel Islands were brought into captivity for safe keeping until those threats could be mitigated. While in captivity, reproductive monitoring of these species revealed information important to their recovery and of basic scientific interest. Our work with Mexican wolves, focused originally on semen banking, found an inverse correlation between sperm quality and inbreeding coefficient. The three founder lineages were highly inbred before zoos began population management. After the lineages were crossed, sperm quality of offspring improved and became equivalent to that of generic gray wolves. We plan to evaluate semen from isolated populations of free-ranging wolves to determine whether sperm quality is typically affected by inbreeding in this species. During endocrine monitoring of island fox reproduction, we discovered that they are induced ovulators. Females with males showed hormone profiles typical of other canids, but females housed alone or with other females experienced little or no hormone fluctuation. This result was surprising, since all other canids are thought to ovulate spontaneously, including the closely related gray fox on the mainland. Captive breeding may not be necessary or even appropriate for all endangered species, but in many cases it has proven critical to recovery. Research and monitoring of captive animals increase our understanding of basic biological processes and contribute to our ability to manage them well.