Imagine being a cougar in Yellowstone National Park in the northern USA. Until the mid-1990s, you were the area\u2019s top predator and could take down the abundant elk \u2013 herbivores very closely related to European red deer \u2013 almost at will.<\/p>\n
Then something changed. Wolves<\/a> were reintroduced and have slowly increased in number.<\/p>\n Over time, the cougars<\/a> found that they might go to the energy expense and danger of bringing down a massive elk<\/a> \u2013 an adult can weigh anything from 200 to 500kg \u2013\u00a0and then face losing it to a bunch of the newcomers.<\/p>\n Because, even though a cougar (especially a male) is usually bigger than a grey wolf, it can\u2019t compete with another carnivore that goes around in packs of up to 10 animals.\u00a0<\/p>\n According to\u00a0new research<\/a>\u00a0published by scientists from Oregon State University<\/a>, the cougars now avoid those areas where wolves make their kills and stay closer to trees they can climb as a means of escape if necessary.<\/p>\n And instead of trying to compete with wolves for the declining number of elk, they have switched their attention to smaller prey \u2013\u00a0mule and white-tailed deer.\u00a0<\/p>\n Remote cameras capture cougars and wolves hunting and scavenging for prey in Yellowstone National Park. Credit: Oregon State University<\/p>\n Comparing data for cougar kills between 1998 and 2005 with those made between 2016 and 2024, the researchers found the ratio of elk in their diet dropped from 80 to 52 per cent, while deer predation increased from 15 to 42 per cent.<\/p>\n Lead researcher Wesley Binder doesn\u2019t think cougars understand there is a greater risk to themselves or that they may risk losing their meal if they take elk because of the presence of wolves in the park.<\/p>\n \u201cWe do not think cougars are able to connect the dots and instead hunt what is available,\u201d he says. \u201cWe see variation in prey selection based on the age and size of the cougar \u2013\u00a0younger and smaller females tend to hunt more deer, while older, larger males hunt more elk.\u201d<\/p>\n Binder says it\u2019s important to understand how two top predators can affect each other\u2019s behaviour and that the coexistence of wolves and cougars depends on prey diversity as much as prey abundance.\u00a0<\/p>\n After heavy persecution of both species in the first half of the 20th century, cougar populations began to rebound in the 1960s and 70s, followed by wolves at least two decades later.\u00a0<\/p>\n This research, says Binder, will give wildlife managers in other parts of North America an idea of what to expect where both species are returning to ecosystems. It suggests the impact may not be additive on prey because cougars can switch what they hunt.\u00a0\u00a0<\/p>\n<\/p>\n Lead researcher Wesley Binder reveals more about the interactions between wolves and cougars in Yellowstone National Park. Credit: Oregon State University<\/p>\n