P-53 was found dead in the Santa Monica Mountains in summer 2019. Researchers did not find a cause of death for the four-year-old cat. Her carcass was too decomposed by the time biologists reached her in Malibu. Testing, however, did identify four different compounds of anticoagulant rodenticide in her liver.
This cat is believed to be the sole survivor of P-23’s litter from summer 2015. When researchers went to the den, there was only one kitten found. That kitten, P-43, and an unknown sibling were later found dead, killed by another animal. And that seemed to be the grisly end of that litter. But then researchers noticed P-23’s movements were still consistent with traveling with young. A remote camera was placed at a deer kill site and, lo and behold, there was another kitten! Researchers waited until she had grown large enough to wear a GPS radio collar, which was in July 2016. The GPS collar later dropped off of P-53, according to the programmed schedule (and before the biologist was able to recapture her and replace the battery).
In March 2019, National Park Service researchers re-captured P-53 and treated her for mange, a parasitic disease of the hair and skin. Mange is generally rare in wild cats, however, it has been widespread in bobcats in the Santa Monica Mountains area since an epizootic started in 2002 caused extensive mortality and a significant population decline.
This is the fifth case of mange in mountain lions since the study began in 2002.