Mounting mountain lion questions: Are cats getting sicker, are they more in our midst?
Quick Take
Sightings of mountain lions, some unhealthy looking, have caused concern for the big-cat population — and public safety — especially after the CZU fire. But scientists say fires are unlikely to be a serious stressor for the cats, and that technology might be making people more aware of their whereabouts.
On New Year’s Eve, Santa Cruz authorities responded to a mountain lion patrolling the Cypress Point Apartments by Neary Lagoon. The wild animal’s appearance in an urban setting was startling, but even more unsettling was the cat’s condition: absolutely emaciated. It was clear to even the untrained eye that this cat was on death’s door.
California Fish and Wildlife staff captured the lion, later confirmed to be a male between five and seven years old, and transported him to the Oakland Zoo for treatment. The lion was “obviously very unwell,” said Colleen Kinzley, the Zoo’s vice president for animal care, conservation, and research. The staff did their best for him, but he died on Jan. 2.
After the cat’s sighting in such an unexpected environment, and obviously poor condition, concern for the health of mountain lions — and public safety — has been a topic of much discussion, especially on social media, where sightings are often reported by residents in well-populated parts of Santa Cruz, Scotts Valley and other communities.
Just days after the dramatic event, another mountain lion was seen on a security camera in Boulder Creek. He seemed to be limping, and Wildlife Emergency Services, a local volunteer-run non-profit, wrote in a social media post that he appeared “sickly.”
The organization raised the questions many locals have shared about the lions: ”Is their condition related to the fires that ravaged through these mountains, is it something in the water, like fire retardant, is it exposure to rodenticides, or something else?”
Experts weigh in
Experts say local fears that mountain lions are being driven into urban areas to look for prey because their habitat has been destroyed are mostly unfounded. “I would be very surprised if this had anything to do with fires,” said Chris Wilmers, director of UC Santa Cruz’s Puma Project.
Justin Dellinger, another mountain lion researcher with the California Department of Fish and Wildlife, agreed. “They’re pretty skilled at finding food,” he said. Dellinger and Rudd both said that home security cameras can often contribute to a feeling that wildlife sightings are increasing, which could make residents feel the lions are encroaching in unusual areas.
“These security cameras, doorbell cameras, everything else. Now people are just learning what’s always been there in the night,” said Dellinger.
Lions, if they have a choice, definitely don’t often like hanging out in the urban areas. “However, places like Santa Cruz, it’s kind of diffusely built into the woods,” he said. “What that does is it creates a lot more edge habitat, which inherently draws in all the things that mountain lions like to eat.”
Rudd said a healthy lion could be just as likely as a sick or starving one to venture into an urban area to pick up a raccoon, especially if there’s green space nearby — which is true for many areas in Santa Cruz County.
Residents of Santa Cruz County are understandably concerned about ecological disturbance after the fire. The CZU fire was unprecedented in size and intensity for this area, and may have effects unlike other wildfires.
But, if previous history is any indicator, the animals will adapt just fine — and residents will be under no greater threat of a mountain lion attack than before the fires.
The coroner’s (preliminary) report
Jaime Rudd works for the Department of Fish and Wildlife in the Wildlife Investigations unit. She performs necropsies — the animal versions of autopsies — on mountain lions and other large mammals that die in unusual circumstances. It’s her job to determine the cause of death and look for disease or pesticide exposure.
Rudd performed the necropsy on the New Year’s Eve lion after he died.
“He was emaciated, he had a lot of muscle wastage, a lot of muscle atrophy, was dehydrated,” she said. “But he also had just a lot of nonspecific changes to his major organs that could be suggestive of something more chronic, more ongoing like disease.” He was so wasted away, in fact, the lab couldn’t take X-Rays.
Most significantly, Rudd and her team found a perforation in his upper small intestine, just below the stomach, that was causing a leak of gastric fluid, “possibly into his abdominal cavity,” Rudd said. This perforation, she believes, is likely what led to his eventual death.
-
Track mountain lions virtuallyUC Santa Cruz’s Puma Project includes an online mapping tool that tracks lions that have been collared.
Rudd said she didn’t know how the perforation happened, or whether it was an acute occurrence — something that immediately led to rapid deterioration — or a chronic problem that worsened over time. “That’s something that I’m not going to know until I get further lab results back,” likely in February, she said. Some of the possible causes are bones from a meal damaging his intestine, or bacteria causing an ulcer.
But while she was saddened by the state of the lion, his capture did not set off major alarm bells.
While reluctant to make definitive conclusions before the full toxicology and other lab reports were complete, Rudd thought it was unlikely that either rodenticides (poisons designed to kill rats, mice and other rodents) or post-fire starvation were the cause of this animal’s distress — or that they are major threats to the Santa Cruz County mountain lion population as a whole. Locals have expressed concerns about the impact of both factors on big cats.
Emaciation is a common — though serious — condition in mountain lions. “Lions have such a really high metabolic demand,” said Rudd. “What we’ve learned from some of the collar [tracking] studies is that they can go from a really good body condition to almost the condition of this animal in a really short period of time. Less than a month, like within three weeks.”
Anticoagulant rodenticides, which are a serious problem for many kinds of wildlife because they impede their blood from clotting, are unlikely to have caused the animal’s intestinal perforation, or the emaciation observed in this animal and possibly the lion spotted recently in Ben Lomond. Animals killed by anticoagulant rodenticides are usually found in overall good health, but they’ve bled to death.
Wider analysis
Rudd recently concluded a years-long surveillance study in which she and her colleagues performed necropsies on 111 California mountain lions to assess their general health and exposure to anticoagulant rodenticide, among other things. It was a sort of “state of the state on mountain lions in California,” as she called it.
In the “state of the state,” 105 of the 111 lions had anticoagulant exposure. But the rodenticides were not the cause of death for any of those animals, and they weren’t able to find a correlation between body condition and rodenticide exposure.
“It’s a complicated topic, Rudd said. “I’m not trying to say it’s not a problem. We just don’t really know. But we know that it wasn’t leading to the mortality of those individuals.”
The CZU fire, though absolutely devastating, is also unlikely to have been what caused this animal to starve.
Dellinger said that in his research tracking mountain lions, he’s seen that they overwhelmingly evade the immediate damage of fires, and he pointed out that their range is usually so vast — around 100 square kilometers or more — that it’s relatively easy for them to relocate as needed to hunt.
In the Santa Monica Mountains, about half of all the mountain lion habitat burned in the Woolsey fire in 2018. But, “this past summer it was the greatest number of kitten litters recorded than in any other time of the 20 years of that project,” Dellinger said.
“I’m not trying to say that we should cut the mountain lion’s habitat in half and that it’ll boost productivity,” he added. ”But those animals, they’re having litters and still going about their day to day, and at a rate that the park service staff hasn’t seen before.”