Pumas in Patagonia started feasting on penguins — but now they’re behaving strangely, a new study finds
Patagonian pumas are preying on penguins – and it’s changing the way the big cats interact with each other.
The pumas in question resettled in an Argentinian national park home to a penguin breeding colony – and the cats quickly began eating the birds. It now turns out that the normally solitary cats that eat penguins tolerate each other more often than expected, according to a new study published Wednesday (December 17) in the Proceedings of the Royal Society B reports.
“Restoring wildlife to today’s altered landscapes does not simply return ecosystems to the past,” said the study co-author. Mitchell Serotaecologist at Duke Farms in New Jersey. “This can create entirely new interactions that reshape animal behavior and populations in unexpected ways.”
Patagonian sheep herders drove mountain lions from the region in the 20th century. After Monte Leon National Park was established in 2004, pumas began to return. But in the absence of mountain lions, other species have adapted to the reduced hunting pressure. For example, a group of Magellanic penguins (Spheniscus magellanicus), generally confined to offshore islands, has established a breeding colony on the mainland consisting of some 40,000 breeding pairs.
Shortly after the park was established, researchers began noticing penguin remains in mountain lion droppings. Mountain lions took advantage of the altered ecosystem.
“We thought it was just a few people doing this,” said Serota, who conducted the research while he was a doctoral student at the University of California, Berkeley. “But when we got there…we noticed a ton of mountain lion detections near the penguin colony.”
In the new study, researchers used cameras to estimate how many pumas lived near the penguin breeding colony, a 2-kilometer beach inside the national park. They also tracked 14 individual pumas with GPS collars and surveyed penguin mortality sites over several field seasons between 2019 and 2023. Nine of the pumas they tracked hunted penguins, while five did not.
The study found that mountain lions that ate penguins showed greater variation in their range from season to season. The penguin-eating cats stayed near the penguin colony when the birds were in the national park during the breeding season. But they extended about twice as far when the birds migrated offshore during the summer.
Penguin-eating pumas also interacted more often with each other than pumas that depended on other prey. Researchers documented 254 encounters between two pumas both eating penguins, and only four encounters between pumas where neither ate penguins. Most puma encounters took place within 1 km of the penguin colony.
Given that several pumas used the colony as a food source, this disparity suggests that penguin-eating pumas are more tolerant of other pumas than those that rely on other prey, likely because they do not have to compete as much for abundant food. In fact, researchers found that the density of pumas in the park was more than twice the highest concentration previously recorded in Argentina. Usually, adult pumas are solitary and establish large territories to ensure they have enough prey to feed themselves and their kittens.
Understanding how large carnivores behave when they return to human-impacted ecosystems “is essential for conservation planning because it allows managers to…design management strategies based on how ecosystems actually function today, not how we assume they should function based on the past.” » Juan Ignacio Zanon Martíneza population ecologist from Argentina’s National Council for Scientific and Technical Research (CONICET) who was not involved in the study, wrote in an email to Live Science.
Knowing how puma behavior affects both cats and penguins could help the park’s future conservation efforts.
For example, mountain lion predation might not have a major effect on large breeding colonies, but it could affect the growth of new, smaller colonies. It is a “complex situation for the people who manage the area, because there are two indigenous [species] interact,” in a way different from what it was before human activities changed the ecosystem, said Javier Cianciobiologist at CONICET who did not participate in the new study.
In future work, Serota says the team will study how the relationship between pumas and penguins affects other puma prey, such as guanaco (Guanicoe lama), a relative of the llama.
