When a big cat comes up against a flightless bird, there’s a clear winner. Within just a few years, pumas have killed thousands of penguins in Argentine Patagonia. Cattle farming evicted pumas from their historic range in southern Argentina during the 20th century. Finding an area free of predators, penguins moved from their island homes to Monte León National Park on the mainland. But now that cattle farming is largely abandoned in the region, pumas (Puma concolor) are back—and the defenseless Magellanic penguins (Spheniscus magellanicus) are having to deal with an apex predator for the first time. Scientists estimated that the pumas along the Argentine coast have killed more than 7,000 penguins—about 7.6% of the colony’s entire population—from 2007 to 2010. The vast majority of the penguin carcasses were found uneaten by the pumas, a behavior that scientists call surplus killing. “The number of carcasses showing signs of predation we found in the colony is overwhelming, and the fact that they were left uneaten means pumas were killing more penguins than they required for food,” said Melisa Lera, a postgraduate student at Oxford University and lead author of research published in Journal for Nature Conservation. Based on population modeling, however, scientists don’t think the predation will be a long-term problem for the penguins. The colony is threatened instead by low breeding success and juvenile survival.
