NEW YORK. – The Penguins in the southern seas have to fear being captured by seals or hunted by killer whales. On land they can find safety when they are in a group. But in the region Argentine PatagoniaThese flightless seabirds become a snack for an unexpected land predator: the cougars.
New research published Wednesday in the journal Proceedings of the Royal Society Boffers “a nice mix of animal movements and who eats what,” said Jake Goheen, a wildlife ecologist at Iowa State University who was not involved in the research.
He found that pumas prefer to hunt herbivorous mammals rather than small birds like Magellanic penguins.
“It’s an extraordinary example of how flexible large carnivores can be,” Goheen said.
At the beginning of the 20th century, Patagonian pumas were wiped out by widespread sheep farming. With the disappearance of these predators, Magellanic penguins, which had lived primarily on oceanic islands, formed large breeding colonies on the Argentine coast. Conservation efforts have brought cougars back into the landscape, laying the foundation for new interactions between these animals.
Mitchell Serota, ecologist and lead author of the study, was interested in how Magellanic penguins, as a new food source, changed puma movement patterns across the landscape. I was also curious about how cougars interact with each other and what their population density is.
To understand behavioral changes, Serota, who completed the research at the University of California at Berkeley, and some of his colleagues fitted 14 pumas in Monte León National Park with collars with GPS trackers. They collected data from 2019 to 2023. Because penguins are migratory animals and only stay in the park’s breeding colony for half a year, scientists tracked how the pumas moved and interacted over the seasons.
They found that the pumas’ behavior changed the more time they spent near the penguin colony. Cougars that hunted penguins had smaller territories than those that didn’t, and the big cats interacted with each other more often in the colony.
Briana Abrahms, a wildlife ecologist at the University of Washington who was not involved in the research, was familiar with cougar attacks on penguins. He had been studying a penguin colony north of Monte León and thought the attacks were relatively unusual.
“What surprised me at first, although I think it makes a lot of sense, is just the level of predation that’s occurring on these penguins,” he said, “and how much the cougars have adapted to this new food source.”
After integrating GPS tracking with camera trap data, scientists also discovered what may be the highest density of mountain lions ever documented in a single location, Serota said. Although cougars are typically solitary animals, their population density in this area was about twice as high as elsewhere, leading to an increase in interactions between the cats.
Serota compared their presence to that of brown bears, which tolerate each other during the salmon migration. “Penguins seem to do something similar to cougars,” he said. “Food can unite predators.”
Changes in ecosystems can influence when, where and how predators obtain their food, which has far-reaching ecological implications. These ecological impacts are still unknown for the region’s pumas, which typically feed on guanacos, llama-like herbivores.
“Because cougars and guanacos form the dominant predator-prey relationship in the region, changes in the way cougars move and hunt can have a huge impact,” Serota said.
Helpless penguins, easy prey for pumas, could even get caught up in this chain reaction. “Will we see a situation in the future where penguins return to living primarily on oceanic islands?” Goheen said.
For Serota, the study showed that a new predator-prey relationship, like the one that exists between pumas and penguins, is changing the ecosystem.
“Restoring wildlife in today’s changing landscapes does not simply mean returning ecosystems to the past,” Serota said. “It can create entirely new interactions that change animal behavior and populations in truly unexpected ways.”
It is often assumed in the scientific literature that the reintroduction of large carnivores can return an ecosystem to the state it was in before. But other things have changed in the absence of carnivores. “Carnivores are being reintroduced into an ecosystem that is not necessarily similar to the one in which they became locally extinct,” Goheen said. Animals face new situations.
“As scientists, we have to come to terms with this,” he said, “and not sell the general public on the idea that if we revive carnivores, in a chain reaction they will have all sorts of benefits for the rest of the ecosystem.”
He added: “We need to reintroduce carnivores because they deserve to be there and because we were the ones who wiped them out in the first place.”
Qor Alexa Robles Gil
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