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 pumas 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 pumas’ position in animal hierarchies by reviewing past research assessing interactions between pumas 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 pumas are subordinate to grizzly bears, black bears, wolves, and jaguars, but dominant over coyotes and maned wolves.
Pumas 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 puma lives more difficult, or, at minimum, reduce hunting where dominant competitors are expanding their range into areas where pumas were the top carnivore?
Wolves seem to influence pumas the strongest. When they live with wolves, pumas 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 pumas, frequently chase and harass them, and push them from their kills. In three puma-wolf studies in the Northern Rocky Mountains, wolf reintroductions and natural recolonization appeared to increase starvation among pumas. Pumas, 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 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.
Wolf packs also appear to have a clear advantage over individual pumas—but one-on-one, the outcome of competitive interactions between these species is less certain, or dependent upon differences in age (e.g. adult pumas 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 pumas and other apex carnivores. For one, we don’t know how the negative effects imposed on pumas 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” 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.
Puma populations, unfortunately, are very difficult and very expensive to track, so declines may go undetected for some time. Therefore, we recommend reducing puma hunting in areas where wolves and grizzly bears are expanding their range, until we know for certain how pumas will be affected by these species.