A new study by researchers at UC Santa Cruz suggests that mountain lions in Santa Cruz do not make accurate assessments of where they are most likely to be killed by humans, especially in regarding the threat of being killed in retaliation for the loss of livestock.
Cougars fear humans and modify their behavior to avoid densely populated areas, where human activity is most evident. But it’s actually the areas of intermediate housing density that prove the deadliest for mountain lions in the Santa Cruz Mountains. This is largely because these areas are the site of conflicts over livestock. Between 2009 and 2019, the leading cause of mountain lion deaths in the region was “retaliatory killings,” where a landowner kills a mountain lion for hunting livestock, most often goats kept in small numbers on rural residential properties. .
Researchers analyzed data on retaliatory killings over this 10-year period and found that they accounted for 36% of total cougar mortality and the majority of human-caused deaths. The team then looked for patterns of risk distribution of these killings in space and time. They compared this with tracking data from cougars fitted with GPS collars, which shows how cats choose their habitats. This comparison demonstrated what is likely a discrepancy between the mountain lion’s perception of risk and the actual human risk over 17% of the study area.
Chris Wilmers, professor of environmental studies who directs the Project Santa Cruz Puma, was the lead author of the paper, and Anna Nisi, a former graduate researcher from Wilmers’ lab, was the lead author of the study. The team believe their findings show that humans are “unpredictable predators” for mountain lions.
“People who commit retaliatory killings are distributed in locations where there are fewer cues related to overall levels of human activity that mountain lions can use to understand risk,” Nisi explained. “So while cougars generally behave in ways that avoid encountering humans, there are places that they feel are safe that actually carry a lot of risk.”
Cougars tended to avoid regions of intermediate housing density during the day, but they actually seemed to prefer these high-risk habitats at night. The researchers found no indication that this was related to hunting behavior. Pets make up just 4% of the cougars’ diet, and the team’s analysis showed cougars killed to prey on livestock weren’t leaner than others and didn’t last long. longer since the last killing of their main food source: deer. This means that cougars were probably not attracted to these areas due to the possibility of eating livestock. The research team has a different theory.
“The spatial requirements of cougars are quite large, which means that in the Santa Cruz Mountains most animals have some degree of habitat fragmentation within their home ranges,” Nisi said. “We think the reason we see them using these areas of intermediate housing density at night is that they just need to get through these spaces, so they end up doing it at night, when there’s less of a chance of meet a person.”
Unfortunately, crossing these areas at night does not spare cougars from chance encounters with livestock. And if a mountain lion takes the opportunity for an easy meal, then it may become the target of retaliation. Hunting or killing cougars has been illegal in California since 1990, but there are exceptions for the protection of livestock. The California Department of Fish and Wildlife issues “depredation permits” that allow cougars to be killed in verified cases when a domestic animal has been attacked.
The vast majority of reprisal killings analyzed in the study were authorized. However, after the study period, the process for issuing depredation permits in the Santa Cruz Mountains changed significantly. In 2020, local cougars received temporary special protections as part of a proposal to list certain regional cougar populations under the California Endangered Species Act. These temporary protections require a step-by-step process of non-lethal efforts to deter cougars before a depredation permit can be issued.
Nisi says improving animal care practices — like keeping livestock in a covered pen at night — can significantly reduce the risk of mountain lions attacking pets. If the proposal to list local cougars under the California Endangered Species Act is approved, these types of non-lethal measures could become a first resort on a more permanent basis. Additionally, Chris Wilmers, who has been studying local cougars for more than a decade, says he hopes the new paper’s findings will draw attention to the larger question of how development patterns set the stage for conflicts.
“This study is an example of how low-density peri-urban areas are where we see the most human-wildlife conflict, and it can turn a place that could have been potential habitat into an area to high mortality,” Wilmers said. “I think this should make us think about how much of this kind of sprawl we allow on the landscape, especially since this is the type of development that is growing the fastest in all of the West. American.”