Signs of inbreeding among SoCal lions raise fears of extinction

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LOS ANGELES (CNS) – Scientists tracking two local populations of cougars, one in the Santa Monica Mountains and the other in the Santa Anas, have identified the first reproductive signs of inbreeding among these groups, which are cut off from the breeding options by busy highways.

According to the UCLA-led study – which is available online and will be published in the January 2022 edition of the journal Theriogenology – animals averaged an abnormal sperm count of 93%, while some also had abnormal sperm count. physical signs of inbreeding, such as deformed tails or testes. defaults.


What would you like to know

  • Scientists tracking two local populations of cougars have identified the first reproductive signs of inbreeding among these groups
  • According to the UCLA study, the animals averaged an abnormal sperm count of 93%, while some also showed physical signs of inbreeding, such as deformed tails or testicular defects.
  • The researchers said the findings urgently need wildlife crossings, structures that allow mountain lions and other animals to roam further and find a larger pool of potential mates.
  • The California Department of Transportation has groundbreaking groundwork for early 2022 on a wildlife crossing on Highway 101 in Agoura Hills

Researchers have long had genetic evidence for inbreeding, but malformed sperm is the first evidence that inbreeding occurs in the reproductive system.

“This is a serious problem for an animal that is already endangered locally,” said lead author of the study, Audra Huffmeyer, a postdoctoral researcher at UCLA who studies fertility in large feline species and is a National Geographic explorer. “It’s pretty harsh.”

The researchers said the findings urgently need wildlife crossings, structures for mountain lions and other animals to roam further and find a larger pool of potential mates. Mountain lions – also known as cougars – are a flagship species, making them a leading indicator that inbreeding could soon cause problems for other species in the Santa Monica and Santa Ana mountains, have said the authors.

The California Department of Transportation has scheduled one such wildlife crossing, a bridge over the Ventura Highway (101) in Agoura Hills, to open in early 2022, with a mix of public and private funding.

Biologists and land managers hope this project will lead to more crossings. The first plans are being formulated for a possible structure on Interstate 15 in Riverside County.

The latest study builds on the work of scientists at UCLA, the National Park Service’s Santa Monica Mountains National Recreation Area, and the UC Davis Wildlife Health Center. The NPS and UC Davis are conducting long-term studies of Southern California cougar populations, currently tracking 17 cats.

Over the past year, the research team has identified nine adult males from the Santa Monica and Santa Ana ranges showing signs of inbreeding, including early signs of reduced fertility.

Their results are similar to the signs of severe inbreeding seen early in most Florida panthers in the 1990s, including crooked tails, undescended testes, and teratospermia (60% or more of abnormal sperm), Huffmeyer noted. . The Florida panther population did not recover until the introduction of Texas pumas.

“The Florida panthers were also severely isolated and severely inbred, so the fact that we are seeing the same traits in our population of pumas is alarming,” she said. “If we don’t do anything to introduce more genetic diversity to the mountain lions of southern California, we will have more males with reproductive problems, fewer kittens and a lower kitten survival rate.” “

Scientists have suggested a real risk of extinction for pumas in the Santa Monica and Santa Ana ranges. Once significant inbreeding depression is found – meaning decreased fertility and reduced kitten survival – extinction is expected to occur within 50 years, according to articles from 2016 and 2019 assessing the viability of the kitten. population which included scientists from UCLA, NPS, UC Davis, University of Wyoming and University of Nebraska.

While a few pumas – especially the cougar known as P-22, which frequents Griffith Park – have successfully crossed the freeways, many more have been killed trying to do so.

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