Mountain lions that essentially live in isolation in the Santa Monica Mountains have become dangerously in-bred as genetic diversity diminishes in the population, researchers found in a study published Thursday in Current Biology.
Cut off from a larger habitat by a freeway and housing developments, the mountain lions live in around 410 square miles, roughly half of the roaming range they need to thrive, Science Magazine reported.
Seth Riley, a wildlife ecologist for the National Park Service at the Santa Monica Mountains National Recreation Area, and a research team did genetic analyses for 42 lions that live in the Santa Monica Mountains, KPCC reported.
The scientists found that the cramped mountain lion population had the second-lowest genetic diversity among North American large carnivores, coming in next to the Florida panther. The lions became isolated over time after the Ventura Freeway was built in the 1950s, as housing developments sprang up on either side of the highway.
According to the study, the diminishing diversity in the mountain lion population has caused the big cats to turn against each other. Young lions normally spread outside their birth ranges, especially if they are male.
Researchers found at least seven incidents where lions were killed by other lions; five of the instances were male lions fighting their brothers, own offspring or former mates.
"All of those things really don't seem to make much sense in an evolutionary perspective. The whole goal is to pass your genes on to other generations," Riley said.
To further minimize genetic variety, a male lion known as P1 that scientists tracked for years bred with his own female offspring. Just one new male lion has made its way into the mountain range in the last 10 years, but his successful reproduction gives the population hope.
"The fact that P12 crossed and then became a dominant male, and then he transmitted all of this genetic material from the north into the Santa Monica Mountains, and so he really transformed the genetic structure of the population," Riley said.
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