Inbreeding Causes Anxiety About Mountain Lion Extinction

AGOURA HILLS, CA — Signs of physiological and genetic issues caused by inbreeding have raised concerns of extinction for Southern California mountain lions.

A new University of California, Los Angles-led study examined 12 mountain lions from Dec. 2019 to Dec. 2020 from the Santa Monica and Santa Ana Mountain ranges for signs of a population decline based on inbreeding.

Researchers have already been aware of high rates of inbreeding among Southern California mountain lions; but this newer study detects dangerous physiological and reproductive problems caused by inbreeding.

The animals studied averaged a 93% abnormal sperm rate, while some also displayed physical signs of inbreeding, like deformed tails or testicular defects.

The scientists cited a real risk of extinction for the mountain lions in the Santa Monica and Santa Ana ranges. Once significant inbreeding depression is found — meaning decreased fertility and reduced kitten survival — extinction is predicted to occur within 50 years, according to 2016 and 2019 papers evaluating population viability that included scientists from UCLA, National Parks Service, University of California, Davis, the University of Wyoming and the University of Nebraska.

"These reproductive and physical signs of inbreeding depression in Southern California mountain lions increase the urgency of conservation efforts in the region," the researchers said in the study.

Southern California mountain lions have among the lowest genetic variation of any mountain lion population, matched only by the Florida panther, according to the study. This is largely because freeways separate genetically different populations of mountain lions, according to the study.

Read More: Groundbreaking of Wildlife Crossing in Liberty Canyon Nears

The California Department of Transportation is expected to break ground on a wildlife freeway crossing project to help connect the mountain lions in the Santa Monica Mountains to the mountain lions in Northern California.

City News Service contributed to this story.