Natural systems are not egalitarian. Some animals dominate over others, meaning they consistently win when competing for food, space, or other resources. Dominant species also win in physical fights, which sometimes escalate and result in the death of the loser. Occasionally winners eat losers, but more often they don’t—not all fights are about food.
In a new paper just published in PeerJ, we found that mountain lions are often losers—and subordinate to at least one other apex carnivore in 47.5% of their 22,735,268 square kilometer range across North and South America.
Anna Kusler, a graduate researcher with Panthera’s Teton Cougar Project from Pace University, and I set out to investigate the mountain lion’s position in animal hierarchies by reviewing past research assessing interactions between mountain lions and other large carnivores. We knew they were at the top—but they are not alone, as they share this rank with grizzly bears, wolves, jaguars and several others.
As it turns out, the combined research of the last 60 years strongly suggests that mountain lions are subordinate to grizzly bears, black bears, wolves, and jaguars, but dominant over coyotes and maned wolves.
Mountain lions are heavily regulated through hunting to reduce conflicts with livestock and people, which raises an important question: Should we reduce human hunting where dominant competitors like wolves and bears make mountain lion lives more difficult, or, at minimum, reduce hunting where dominant competitors are expanding their range into areas where mountain lions were the top carnivore?
Wolves seem to influence mountain lions the strongest. When they live with wolves, mountain lions reduce their use of open habitats, where wolves have the advantage, and restrict their movements to forests and cliffy areas where they can easily escape wolves that might pursue them. They also change which prey they hunt when they live with wolves.
Wolves kill all age classes of mountain lions, frequently chase and harass them, and push them from their kills. In three puma-wolf studies in the Northern Rocky Mountains, wolf reintroductions and recolonization increased starvation among mountain lions. Mountain lions, too, occasionally kill wolves.
Past research also suggests that the winners of contests can be predicted by the size of the two animals involved—bigger animals are almost always dominant over smaller. Overall, this seemed to be true for relationships between pumas and other species. For example, evidence that jaguars are dominant over mountain lions is strongest in areas where jaguars are large and weigh considerably more than mountain lions, but more ambiguous in Northern Mexico, where the two species are similar in size.
Wolf packs also appear to have a clear advantage over individual mountain lions—but one-on-one, the outcome of competitive interactions between these species is less certain, or dependent upon differences in age (e.g. adult mountain lions killing young wolves; see Hunters or Hunted? Wolves vs. Mountain Lions).
Our review, if nothing else, highlighted how little we know about the competitive interactions between mountain lions and other apex carnivores. For one, we don’t know how the negative effects imposed on mountain lions by wolves, bears, and jaguars interact with the negative effects of lethal human management.
This means it’s incredibly difficult to determine what is a “sustainable” mountain lion hunt and what is not. Instead, mountain lion management must be reactionary, carefully following populations to determine whether they are in decline, and rapidly adjusting hunting pressure accordingly.
Mountain lion populations, unfortunately, are very difficult and very expensive to track, so declines may go undetected for some time. Therefore, we recommend reducing mountain lion hunting in areas where wolves and grizzly bears are expanding their range, until we know for certain how mountain lions will be affected by these species, as well as the combined effects of hunting and dominant competitors.
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