Effects of male targeted harvest regime on sexual segregation in mountain lion

- Male targeted harvest regimes of mountain lion can have many unintended cascading effects on mountain lion populations.
- Our research found that female mountain lions in a heavily hunted area segregated away from males and spent more time at higher elevations than males or females without kittens.
- This behavior was more pronounced during summer than in winter and may have led to greater predation on declining mule deer.

Male targeted harvest regimes of carnivores are now widely accepted to result in increased sexually selected infanticide (SSI). Male targeted harvest regimes of males should therefore result in increased sexually segregated habitat use in infanticidal carnivores. We tested the effects of low and high levels of male hunting mortality and associated SSI on sexually segregated habitat use in mountain lions. The “no effect of hunting” hypothesis predicts that no sexual segregation would occur or that all female mountain lions would segregate from males because of sexual dimorphism. The “hunting effect” hypothesis predicts that females with kittens would segregate from younger immigrant males in the heavily hunted population during summer when kittens are vulnerable to SSI. We rejected the “no effect” hypothesis and accepted the “hunting effect” hypothesis for mountain lions. Females with kittens avoided immigrant males in the heavily hunted population during summer-others did not. This sexual segregation corresponded with females with kittens selecting for food-poor, high elevations in the heavily hunted population but not in the lightly hunted population. Avoidance of males and selection for high elevations resulted in prey switching by females with kittens from abundant primary prey in lower elevations to rare, sensitive and threatened secondary prey at higher elevations. It appears that remedial sport hunting of mountain lions to reduce predation on declining prey actually caused sexual segregation and increased predation on declining prey. We suggest that excess mortality of male carnivores could result in unanticipated cascade effects including sexual segregation and prey switching to declining prey.