Where the hunting grounds of apex predators overlap, there are always winners and losers. Large carnivores use their brawn to force smaller rivals off meals, or worse: to wipe out the opposition entirely. Others use strength in numbers to gain ground and resources. It's a struggle for dominance that America's second-largest cats know well, a new study shows. 

A map showing where pumas are dominant and subordinate across their range.

Research from global wild-cat conservation organisation Panthera reveals that in almost half of their expansive range across the Americas, pumas are outmatched by at least one other large predator in the contest for food, space and resources. While the cats certainly rank at the top of the food chain, they are forced to share this position with contenders like wolves, bears and jaguars. The study found that pumas came off second best to other large predators in as much as 47.5% of their 22,735,268 square-kilometre range – a habitat that's greater than any other large land mammal in the Western Hemisphere.

To figure out just how the tawny cats stacked up against their carnivorous competition, Panthera Puma Program lead scientist, Dr Mark Elbroch, and Anna Kusler, a graduate researcher with Panthera's Teton Cougar Project, combed through 60 years of scientific literature and flagged anything featuring interactions between mountain lions and other carnivores (hardly glamorous, but wildlife research isn't all darting elephants and tracking jaguars). Using 64 sources to assess dominance among pumas and other apex predators, they found that pumas are often outranked by black bears, grizzlies, wolves and jaguars, but are dominant over maned wolves and coyotes.

"Wolves seem to influence pumas the strongest," Dr Elbroch writes in a blog post outlining the findings. "Wolves kill all age classes of pumas, frequently chase and harass them, and push them from their kills." Where wolves and mountain lions share ground, it's the cats that are usually forced to surrender territory, shifting their movements away from open plains, and instead skulking in forests and over rockier terrain to better evade prowling wolves. The big cats may even adjust their prey preferences, targeting deer and other animals rather than elk.

A puma monitored by Panthera pushed off his kill by a wolf. 

Pumas don't always settle for the subordinate position, though; the cats sometimes emerge victorious in scuffles with rivals, and have even been recorded killing their canid adversaries on occasion (usually lone wolves that lacked the competitive edge that comes with rolling in a pack). For predators jostling for top spot on the food chain, strength in numbers can make a big difference. Wolves outranked pumas in 78% of the sources turned up by Elbroch and Kusler – an impressive track record that mostly came down to a numbers advantage.

Size plays a big role, too. Larger animals will almost always come out on top, which is why pumas outrank smaller mesocarnivores like ocelots and lynxes, but often lose to the far heftier bear species. But when it comes to jaguars, the contest is a little less clear-cut. "Evidence that jaguars are dominant over pumas is strongest in areas where jaguars are large and weigh considerably more than pumas, but more ambiguous in Northern Mexico, where the two species are similar in size," Elbroch explains. It's unclear if pumas actually outrank their spotted cousins (that's a research topic waiting to be explored), but the results of the study show that size certainly does matter.

The apex predators of North and South America and their relative competitive relationship with pumas (E). Bold arrows denote dominance, and point from the dominant species to the subordinate. Thin arrows denote some evidence to the contrary. (A) gray wolf (Canis lupus), (B) grizzly bear (Ursus arctos), (C) American black bear (Ursus americanus), (D) jaguar (Panthera unca), (E) puma (Puma concolor), (F) maned wolf (Chrysocyon brachyurus), (G) coyote (Canis latrans). Drawings by Mark Elbroch/Panthera

Clashes for the number-one spot among America's large carnivores are complex, and there's still much we don't understand about these interactions, or the impact they have on the ecology of the species involved (and the other critters that depend on them). Puma numbers are heavily controlled through hunting in order to reduce conflict with livestock and humans – clashes that are almost inevitable for a cat with such a massive home range. For Elbroch, it's important to understand how predator dominance affects these cats before we put them in the crosshairs.

"It's incredibly difficult to determine what is a 'sustainable' puma hunt and what is not – instead, puma management must be reactionary, carefully following populations to determine whether they are in decline, and rapidly adjusting hunting pressure accordingly," he argues.

Until we better grasp the impact of other carnivores on mountain-lion populations, hunting should be reduced – at least in areas where wolves and grizzlies are expanding their range, says Elbroch. If the cats can't cope with competition from other predators, they certainly don't need any more from us.