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A keystone species is a species that is responsible for the natural balance in an ecosystem. A keystone species can be a plant or an animal that plays a vital and unique role in an ecosystem’s functioning. These species may be small in number, but they significantly impact biodiversity and other species populations.

A tremendous change occurs when a keystone species is removed from an ecosystem. One species will significantly increase in population leading to the possible extinction of another species.


Their natural prey thrives if a keystone predator is eliminated from an ecosystem. An increase in their prey numbers means the animals this prey feeds on will dramatically decrease in population. For this reason, the presence of keystone species is very significant.

Here are ten of the keystone mammals of North America.

 Brown Bear

Grizzly bear

Brown bears or grizzly bears act as nature’s gardeners. Brown bears do not solely prey on animals. They also eat roots, seeds, nuts, and bulbs. When looking for sources and bulbs, they dig into the ground, turning over soils in the terrain. 

As a result, brown bears unknowingly aerate the soil and mix organic materials already in the ground. Also, grizzly bears carry and distribute various seeds through their feces. These seeds later grow into shrubs and trees.

Grizzly bears also like to eat salmon. They often carry the fish deep into the forest and eat it there. This type of fish is rich in phosphorus and nitrogen, all essential nutrients for the soil. Leftover carcasses and feces from this animal enrich the forest soil with these nutrients.

Grizzly bears are predators that help regulate the numbers of some species, such as moose. They hunt down these animals on occasion and feed on their flesh. If brown bears were not around, moose would thrive in their natural habitat.

If you want to learn more about the brown bear, I have compiled 101 facts, which you can read here.

Gray Wolf

Gray wolves are one of North America‚Äôs top predators and are vital to an ecosystem’s existence. Typically, in a habitat, there exist many herbivores. With so many animals that depend on vegetation as food, they compete significantly. 

A moose can feed on sixty pounds of vegetation in a single day. If the moose population grows, less vegetation will be left to meet other herbivores’ requirements.

This is where the role of the gray wolf becomes essential. Gray wolves prey on moose, deer, and rabbits, some of the main herbivores in North America. 

Gray wolves keep their populations in check and reduce competition for vegetation. Due to gray wolves, there is no overgrazing and plenty of greenery for all wildlife.

I have written a complete guide if you would like further information on the gray wolf. You can read it here.



Beavers are considered engineers of an ecosystem because they create dams across a stream, diverting it. In the past, these animals were hunted for their pelts and to prevent them from altering the landscape. 

However, it is now understood that this intervention is essential to the life of an ecosystem.

The natural dams they create on rivers and wetlands are a habitat for other animals and fish, such as trout and salmon. Salmons thrive the most due to the natural dams beavers create on streams. 

The dam traps fine sediments, and clean water flowing downstream is conducive to salmon laying eggs.

Did you know that beavers do not stop growing? I have written an article on how giant beavers mature. You can read it here.

Prairie Dog

Prairie dog

Prairie dogs can be found in most grasslands in North America. These animals are mainly herbivores and prefer to graze on plants and grasses. When they feed on grass, they strike a balance and diversity in plants, attracting more insects and birds.

Another thing is that they have a positive impact on the water cycle. Feeding on vegetation reduces water loss from the soil through vegetation. This is especially important during the dry seasons. 

During dry weather, there is less evaporation of water from plant surfaces. Moisture is kept in the soil, plants can thrive longer, and the landscape remains green for much longer.

Prairie dogs also like to burrow. This acts to aerate the soil, adding organic matter, such as their droppings. Their burrowing also allows water to seep underground. On other occasions, their burrows provide shelter to other wildlife.

Have you ever wondered why prairie dogs kiss? I have written an article explaining this here.

Mountain Lion

Mountain lion

Mountain lions are a top predator and a keystone species. Mountain lions maintain balance in the ecosystem by preventing the overpopulation of their natural prey. These animals also aid in avoiding overgrazing. 

Mountain lions prey on moose and deer. However, given a chance, they will kill and eat most animals, including rabbits and porcupines.

Mountain lions must feed on at least ten pounds of the flesh daily. For this reason, they are excellent at regulating prey populations in a habitat. The high population of their game being herbivores such as moose means there will be more vegetation. 

Without mountain lions, many other animals that depend on plants as their food sources would ultimately die of starvation.

Ever wondered if mountain lions attack people? Find out in an article I have written.

Sea Otter

Sea otters are mammals found in the Northern Pacific ocean. These animals ensure the coastal marine ecosystem is kept in check. Sea otters eat sea urchins, and one of the primary sources of food for sea urchins is kelp or seaweed. 

Several organisms, such as snails and crabs, rely on kelp as their food. Without sea otters, there would not be enough kelp to feed other populations of animals. Because the sea otters regulate the sea urchin population, other species that feed on kelp continue to thrive.

Kelp also reduces soil erosion at the coast by slowing down the speed and impact of the sea. Kelp also mitigates adverse climatic changes by absorbing carbon dioxide from the air.

If you want to know why otters hold hands, I have written an article here.

Snowshoe Hare

Snowshoe hare

The snowshoe hare has a large population, making it different from many other keystone species. Unfortunately for the snowshoe hare, they are on this list because they prey on many predators. 

They mainly inhabit boreal forests in Canada, and in this area, the snowshoe hare is prey for several predators. They are among the primary food sources for many carnivores inhabiting the forest.

If snowshoe hares were removed from their ecosystem, many predators would lack enough food to survive. This means there would be no balance between prey and predators in the ecosystem.

As a result, some species would disappear, or their populations will decrease.

For 101 facts about snowshoe hares, click here.


Jaguars are unique and vital keystone species. They are apex predators that have a preference for larger prey. Their food preference is quite broad, including about eighty-seven species of animals. 

The reason why jaguars are a keystone species is due to their diverse diet. They help keep the presence of each one of these species manageable in their ecosystem.

Jaguars feed on birds, turtles, reptiles, monkeys, frogs, rodents, and deer, among many others. Their diet mainly consists of large prey such as deer. 

For this reason, jaguars control the population levels of these animals. The absence of jaguars will mean an increase in the population of various animals in an ecosystem.  

This could negatively affect the ecosystem, such as a lack of food for wildlife that feeds on vegetation. Also, competition for food would result in overgrazing, and an adverse effect on the environment, such as soil erosion. 

For more information on jaguars, check out 101 facts I have written here.


The caribou may not be a predator, but significantly affects other species and its ecosystem. Typically, these animals fall under the category of prey in the food chain, but the caribou are vital for an ecosystem’s existence. 

Apex predators like to feed on larger prey, such as the caribou. When there are no more caribous in the habitat, many top predators will have less food. Some of these animals will start dying of starvation. 

In this case, the presence of other prey will increase because there are fewer predators. Ultimately, the result would be overpopulation, overgrazing, and higher competition for food.

Caribou are grazers, and lichen makes up the more significant part of their diet. However, they also feed on grasses, birch, and foliage in willow trees. The absence of caribou would cause some specific plant species to take over more prominent sections of the forest. 

Lichens are their primary food source; without caribou, there would be too many lichens in their habitat. Without the caribou, there would be no balance in the ecosystem.

Kangaroo Rat

Kangaroo Rat

Kangaroo rats are considered a keystone species because they play a role in keeping the ecosystem healthy. These small animals are prey to a variety of predators, including burrowing owls, coyotes, snakes, and squirrels. Many of these predators would be adversely affected if kangaroo rats disappeared.

Additionally, kangaroo rats make underground burrows. These burrows shelter other animals, such as squirrels and lizards. 

Their burrowing also works to aerate the soil and provides channels for water to enter the ground and mix organic matter. This makes the land suitable for the growth of healthy and robust vegetation. 

When kangaroo rats eat nuts and seeds, they disperse them to different locations through their droppings. This activity encourages the growth of other plant species in the entire habitat.

As we can see, some keystone species are predators, but just as important are the animals on this list that are classed as prey. Without any of the above animals in the environment, habitats would completely change, leading to many animals and plants’ loss.