Mountain lions with crooked tails have been spotted in the Santa Monica mountains, an unsettling sign of extremely low genetic diversity within an isolated population of less than two dozen individuals roaming the rugged canyonlands just north of Los Angeles.
In early March, biologists examined a young sedated male mountain lion. The cougar, designated P-81, had a kinked tail shaped like the letter “L” and only one descended testicle, a condition known as cryptorchidism.
“That was alarming to see,” says Jeff Sikich, a biologist with the Santa Monica Mountains National Recreational Area and an expert on local mountain lion populations. “It’s something we have feared might happen without any new animals coming in and mixing up the genetic diversity in our mountains.”
Since then scientists have found two more big cats with similar deformities. The researchers suspect that one of them is closely related to the first cougar, and is possibly even its sibling.
Biologists have long known that inbreeding was a growing risk for the local lion population. The Santa Monica Mountains are surrounded by the 101 Freeway to the north, the Pacific Ocean to the south, and highways and development to the east and west, creating an isolated environment for this group of mountain lions, who face possible extinction. “We’re actually seeing very low levels of genetic diversity; our animals are trapped in here,” adds Sikich. A 2016 study predicted a nearly 100% chance that the lions will be extinct in the mountain range within 50 years due to the genetic bottleneck.
Mountain lions aren’t the only creatures affected. Sprawling development and habitat fragmentation threaten millions of species around the world. Recently panthers living in Florida experienced a similar problem with inbreeding, including the kinked tails and cryptorchidism. Conservationists remedied the situation by importing eight female mountain lions from Texas, raising the population up from around two dozen to an estimated 200 individuals.
Conservationists in southern California are hoping to tackle the problem differently. A potential solution in the works is a wildlife overpass that would include a bridge over the 101 freeway to allow the Santa Monica mountain lions to reconnect with surrounding cougar populations. Construction could begin in late 2021.