Pumas in Patagonia are hunting penguins, and this is changing the way the big cats interact with each other.
The pumas in question have re-established themselves in an Argentine national park where a penguin breeding colony was located, and the cats immediately began eating the birds. Now it turns out that the normally solitary, penguin-eating cats tolerate each other more often than expected, says a new study published Wednesday (December 17) in the journal Proceedings of the Royal Society B reports.
“Restoring rewilding in today's altered landscapes does more than simply return ecosystems to the past,” said study co-author. Mitchell's proverbecologist at Duke Farms in New Jersey. “This could create entirely new interactions that change animal behavior and populations in unexpected ways.”
Sheep farmers in Patagonia displaced pumas 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 pumas, other species have adapted to the reduced hunting pressure. For example, the group of Magellanic penguins (Spheniscus magellanicus), usually found on offshore islands, have established a mainland breeding colony of approximately 40,000 breeding pairs.
Shortly after the park was founded, researchers began noticing penguin remains in puma scat. Cougars have taken advantage of the changed ecosystem.
“We thought there were only a couple of people doing this,” said Serota, who conducted the research while a doctoral student at the University of California, Berkeley. “But when we got there… we noticed a lot of pumas near the penguin colony.”
In the new study, researchers used cameras to estimate how many cougars lived near the penguin colony, a 1.2-mile (2-kilometer) stretch of beach within the national park. They also tracked 14 individual pumas using GPS collars and examined penguin kill sites over several field seasons between 2019 and 2023. Nine of the pumas they tracked were hunting penguins, but five were not.
The study found that pumas that fed on penguins had greater range fluctuations from season to season. Penguin-eating cats stayed close to the penguin colony when the birds were in the national park during the breeding season. But when the birds migrated to sea in the summer, they flew about twice as far.
Pumas that fed on penguins also interacted with each other more often than cougars that relied on other prey. The researchers recorded 254 encounters between any two cougars that ate penguins, and just four encounters between cougars in which neither of them ate penguins. Most puma sightings occurred within 0.6 miles (1 km) of the penguin colony.
Because few pumas used the colony as a food source, this disparity suggests that pumas that feed on penguins tolerate other pumas better than those that rely on other prey, likely because they do not have to compete as much for plentiful food. In fact, researchers found that the density of pumas in the park was more than double the highest concentration previously recorded in Argentina. Typically, adult cougars are solitary and create large ranges in order to 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 develop management strategies based on how ecosystems actually function today, rather than on how we assume they should function based on the past.” Juan Ignacio Zanon Martineza population ecologist at Argentina's National Council of 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 guide future conservation efforts at the park.
For example, cougar predation may not have much impact on large breeding colonies, but may affect the growth of new, smaller colonies. It's a “difficult situation for the people who manage the territory because you have two indigenous people.” [species] interact” in a way that is different from what it was before human activity changed the ecosystem, said Javier Ciancioa biologist at CONICET who was not involved in the new study.
In future work, the team will examine how the relationship between pumas and penguins affects other puma prey, such as guanacos, Serota said.Lama Guanico), a relative of the lama.
