Mountain lions (pumas) are North America's most widely distributed wild cat, yet urban expansion has fragmented their habitat and created conflict that threatens both individual welfare and population viability.
Mountain lion welfare in California and similar urbanising landscapes is shaped by the collision between expanding suburbs and the large territories these solitary predators require. Young males dispersing from natal ranges face the highest mortality risk: they must cross freeways, navigate urban development, and establish territories in a landscape increasingly hostile to large carnivores. Roadkill is a significant mortality source for all age classes. Secondary poisoning from anticoagulant rodenticides — accumulated through eating prey that ingested poison bait — causes a lingering, painful death from internal haemorrhage. The construction of wildlife crossings — most notably the proposed Liberty Canyon crossing over US-101 in California — represents a concrete welfare investment that reduces road mortality and genetic isolation. The alternative — allowing the Santa Monica Mountains population to become inbred and locally extinct within decades — is both a conservation and welfare failure.