Cougar Series

A Cougar’s Ecological Importance

Chapter five explores a cougar's role in the ecosystem, including its important role as an apex predator and ecosystem engineer.

Show Chapter Topics
Hide Topic Overview

A Cougar’s Ecological Importance


As an apex predator, the cougar’s hunting preferences have an impact on everything in their environment from the deer they eat to the flowers that bloom.

As they have no natural enemies, cougars are considered apex predators at the top of their food chain. Cougars help regulate the ungulate population, indirectly affecting vegetation's impact. Studies have shown that in the absence of cougars, prey populations skyrocketed which directly impacted the health of the plant life¹. As a result, 75% of vertebrate species disappeared due to lack of food¹. 

Cougars are critical for healthy ecosystems. More than 200 different species - from beetles to foxes to birds to trees to vegetation - have been documented benefiting from cougar kills, which is why cougars are also known as ecosystem engineers².



Cougar diets vary, as they are opportunistic hunters. Diet preferences can also vary from cat to cat, indicating that a human-cougar conflict may be related to a single cat. They feed mainly on ungulate populations, with females preferring deer and males choosing to feed on larger ungulates, such as moose or elk¹. In fact, the number of cougars in an area is dependent on the availability of such prey².

Cougars typically consume one deer per week. A mom with kittens can consume up to four deer per week, depending on the size of her litter. Young adults tend to consume smaller prey, such as beavers, porcupines, raccoons, and rodents³. Although they prefer to hunt for their food, cougars have been known to scavenge when needed.

The cougar’s primary food source is deer with a preference to hunt young and/or vulnerable ungulates. This hunting strategy helps maintain healthy ungulate populations and reduces the risk of the cougar being injured while hunting. Targeting vulnerable prey in a consistent pattern helps control the ungulate population. Areas without predators tend to have large numbers of ungulates which causes overgrazing of vegetation in that area. The lack of vegetation impacts the lives of hundreds of other species that depend on vegetation for survival. In this regard, cougars and other apex predators are essential in establishing a well-balanced environment where all animals and plants can thrive.

In urban areas, cougars will also prey on small wild animals, such as pigeons and raccoons³. Studies have also found that a cougar’s predation on ungulates in urban environments is consistent with their hunting in the wilderness³. This suggests that the number of ungulates killed per cougar remains consistent regardless of their environment, and the cougar and ungulate populations can be sustained together in an urban environment.

Cougars suffocate their prey with powerful jaws or bite the back of the head or neck. Once a kill has been made, cougars drag their prey back to a cache site, usually in a densely covered area, to consume their meal. The cougar will then stay close to the cache site until they have fully consumed their prey, covering it with dirt, leaves, grass, snow, and other debris between meals to deter scavengers from eating it².

Cougars Effect on Western & Eastern Canada


Cougars are classified a keystone species, as they are critical in maintaining a healthy ecosystem in any given area. A healthy cougar population is an indication of a healthy environment. Their need for a large territory helps control prey species and protect numerous other species that use the same habitat. This has an indirect effect on the health of the plant life and, in turn, benefits all other species in the area.

The absence of this apex predator results in biodiversity loss and general ecosystem decline¹. For instance, the lack of predators allows the ungulate population to grow which directly affects the health of the vegetation, resulting in the loss of a variety of species dependent upon vegetation for survival.

Reintroducing cougars into eastern North America could have several benefits. For instance, cougars can maintain a healthy and appropriate deer population which would preserve vegetation, reduce erosion of rivers and lakes, help control the spread of disease amongst the deer population, and help reduce tick-borne illnesses in humans such as Lyme disease. 

Interestingly, a study has found that the presence of cougars could decrease the amount of car/deer collisions each year by 22%². This would be the equivalent of saving five lives, preventing 680 injuries, and $50 million in damages².  

Cougars also hunt coyotes. Reducing coyote populations grants smaller predators, like foxes, the opportunity to hunt smaller animals, such as mice. In essence, the presence of cougars helps maintain a balanced and healthy ecosystem and promotes sustainable biodiversity.

Next Chapter In Series...

Cougar Life Cycles


What does the life cycle of a cougar look like? Topics like life expectancy, reproduction, and family structures are explained in this chapter.

End of Series

Cougar Life Cycles

You've reached the end of this series! We hope you feel more informed, and better prepared to discuss the topics covered to help educate those around you.