A Mysterious Illness is Sickening Florida Panthers, and No One Knows What's Causing It

Florida wildlife officials are asking for the public's help in figuring out what's disabling wild cats in the state.
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A Florida panther

A Florida panther

The video's perspective is from ground-level, caught by a camera trap hidden in between palm trees and dense grass in southwestern Florida. An adult Florida panther prowls into focus, then stops to wait for her young.

The first juvenile panther to follow her walks unsteadily, its back legs criss-crossing as it weaves into the underbrush. The second collapses before it even makes it fully into frame, its back legs repeatedly giving out as it falls on its side and struggles to drag itself to its feet.

The cat is one victim of a mysterious neurological disorder that has stricken panthers and bobcats in the sunshine state over the past two months. In four counties in Florida, camera traps have recorded cats stumbling and collapsing to the ground in various stages of the illness. State and federal wildlife officials are working to determine the root cause of the sickness and prevent a possible epidemic before it spreads.

Florida panthers—actually an isolated population of Puma concolor, or cougars—were once nearly extinct, with less than three dozen roaming the state's forests. Since receiving protection under the Endangered Species Act in 1973, their population has begun to rebound. The Florida Fish and Wildlife Conservation Commission now estimates that there are between 120 and 230 individuals in the wild. The species still faces significant obstacles to full recovery, including diminished habitat and a limited gene pool that increases their susceptibility to disease.

The FWC received the first footage of a stumbling panther kitten last year; after reviewing still photos from 2017, the New York Times reports, the agency found what appeared to be another animal suffering from the disease. In 2019, officials began to receive additional video of struggling panthers, pulled from security cameras and traps, suggesting that the problem was more widespread than they had originally believed. In a press release, the agency said that in August, a necropsy confirmed neurological damage in a panther and a bobcat, both of which died from unrelated causes.

Dr. Rick Hopkins, a biologist with ecological consulting firm Live Oak Associates, researched cougars in California for 12 years. He said he had never seen symptoms similar to those observed in Florida.

"It is interesting that it has been found predominantly in young animals," he said. Either toxins or disease would be plausible causes, he added.

In an email, FWC spokesperson Carli Segelson wrote that the agency was testing for "various potential toxins, including neurotoxic rodenticides (rat pesticide), as well as infectious diseases and nutritional deficiencies."

Anticoagulant rodenticide in particular has been blamed for cougar deaths dating back to at least 2004, when staff at the Santa Monica Mountains National Recreation Area discovered two mountain lions that had died from internal bleeding caused by the substance. This year, the National Park Service told NBC's Los Angeles affiliate that it had found rat poison in 21 of 22 mountain lions it tested.

Among the other diseases the agency is investigating are distemper, which can be transferred between domestic and wild animals, and cerebellar hypoplasia, a developmental condition where the portion of the brain responsible for motor coordination doesn't develop properly, she said.

For now, the agency is asking that members of the public who see or record a sick panther contact them. You can submit observations at the Florida Fish and Wildlife Conservation Commission's Panther Sightings page.