The possibility that predators choose prey selectively based on age or condition has been suggested but rarely tested. Researchers from Colorado and Utah State Universities examined whether mountain lions (Puma concolor) selectively prey upon mule deer (Odocoileus hemionus) infected with chronic wasting disease, a prion disease. They compared disease prevalence among lion-killed adult (≥2 years old) deer with prevalence among deer taken by hunters in the vicinity of the mountain lion kill sites. The survey suggest that mountain lions in this area actively selected prion-infected individuals when targeting adult mule deer as prey items.
(Source: Biology letters, 23 April 2010, published online before print)