Common Mammals of the Rocky Mountains

The Rocky Mountains are home to about 70 different mammals, which can be found from the lowest foothills all the way up to the highest peaks.  These include many of the more common mammals such as the deer, moose, and chipmunk.  They live in a variety of habitats and range in size from a tiny chipmunk up to a large moose.

In addition to mammals, there are many other kinds of animals that live in the Rocky Mountains.  These include birds, reptiles, and amphibians.  Do you know what it is that makes a mammal a mammal?  Even though there are many different kinds of animals, visitors to the Rocky Mountains often come to view the big mammals, such as elk, bears, and some of the other common mammals.

Common Mammals of the Rocky Mountains


common mammals, beaverAppearance: Brown.  Can be up to 4 feet long.  Tail is flat.

Diet: Herbivore – leaves, bark, twigs, and aquatic plants.

Lifespan:  Up to 24 years.

When Active: Nocturnal.

Fun Facts:  Beavers have an amazing ability to change the landscape, by building dams on rivers and streams.   They are much more comfortable in the water than on land and are good swimmers.  In fact, they can stay underwater for up to 15 minutes!    Beavers live in lodges, which are dome shaped and often located in the middle of a pond.  The lodge can only be entered underwater.

Bighorn Sheep

common mammals, big horn sheepAppearance: Up to 3 1/2 feet tall and 5 feet long.  Males have large curved horns.  Females also have horns, but they are smaller.

Diet:  Herbivore.

Lifespan:  Up to 12 years.

When Active:  Daytime.

Fun Facts:  The horns can weigh up to 30 pounds!  In the fall, males come together and clash horns to see who will get to mate with the females.  They raise up on their back legs; run at each other at high speeds; lower their heads and crash into each other.  The sound can be heard up to a mile away.  Eventually, one will give up and walk away while the winner gets to mate with the female.

Black Bear

common mammals, black bear eat fishAppearance:  Up to 5 or 6 feet long.  They can be black, brown, or cinnamon in color.

Diet:  Omnivore.  They will eat anything such as berries, and fish.

Lifespan:  Up to 20 years.

When Active:  Daytime.

Fun Facts:  They are the most common kind of bear in the Rockies.  Black bears are solitary animals and wander over a very large territory – from 15 to 80 square miles.  Know how to be safe when you are in bear country with kids.

Chipmunk (Least Chipmunk)

common mammals, least chipmunkAppearance:  Small – 7 to 9 inches tall.   5 alternating black and white stripes running down it body from the head to tail.

Diet: Omnivore.

Lifespan:  Up to 3 years.

When Active: Daytime.

Fun Facts:  Chipmunks have a large fur lined pouch in their cheek that they use for carrying nuts and seeds.  Newborn chipmunks are pink and have their eyes closed.  Their mother takes good care of them for many weeks.


common mammals, cougarAppearance:  Up to 5 feet long.

Diet:  Carnivore – they eat everything from deer to small rodents.

Lifespan: Up to 13 years.

When Active:  Mainly at night.

Fun Facts:  Cougars need a lot of room to survive in order to hunt.  They are incredible athletes – able to jump as high as 18 feet or as far as 40 feet, and can run as fast as 40 or 50 mph!  Know how to be safe around cougars with kids.


mammals coyoteAppearance:  Up to 3 feet long and 50 pounds – a medium sized dog – and smaller than a wolf.

Diet:  Omnivore.

Lifespan: Up to 14 years.

When Active: Both during the day and night.

Fun Facts:  They are smart and clever.  In fact they are one of the few animals that has managed to thrive despite the human population growing and taking over land.  They usually live with just their mate and young.  Although, they will come together with others in order to hunt down larger animals.


An elk in the Rocky Mountains

An elk in the Rocky Mountains

Appearance: Up to 5 feet tall and 1,000 pounds. Males have antlers up to 4 feet tall. Their body is light brown like a deer, but their head is a dark brown.

Diet:  Herbivore

Lifespan:  Up to 12 years.

When Active: Daytime.

Fun Facts:  Newborn elk can stand by the time they are 20 minutes old.  Elk are ruminants, meaning they eat their food twice.  First, they bite their food, chew it and swallow it.  Then they regurgitate it, chew it up and swallow it again!

Marmot (Yellow Bellied)

mammals marmotAppearance:  The size of a housecoat.  It has brownish fur.

Diet:  Herbivore – grasses, flowers, and sometimes seeds.

Lifespan:  Up to 15 years.

When Active:  Daytime.

Fun Facts:  They live up in the mountains and hibernate during the cold, snowy winter.  When not hibernating they spend a lot of time sunning themselves on rocks.  They dig a complex system of tunnels and burrows underground and rocks.  These have burrows for hibernation and multiple entrances.


mammals mooseAppearance:  Up to ten feet tall.  Males have a large rack (antlers).

Diet: Herbivore.

Lifespan: Up to 20 years.

When Active:  Daytime.

Fun Facts:  Moose antlers have a large flat area on it from which the antlers extend. That area is shaped in a way that improves the Moose’s hearing and helps males hear female moose.  This gives those males an advantage when it comes to mating and reproduction.  Know how to be safe around moose when hiking with kids.


mammals red squirrelAppearance:  Up to 15 inches, not including the tail.

Diet:  Omnivore.

Lifespan:  Up to 1 1/2 years, but only 25% make it through first year.

When Active:  Daytime.

Fun Facts:  Their four front teeth never stop growing, which is good because they are always gnawing away at nuts.  They bury nuts to save for eating during the winter.  Unfortunately, about 25% of those are stolen by other animals.  To avoid this, they will sometimes fake bury a nut.  They act like they are burying a nut then take the nut and bury it somewhere else.


mammals gray wolf headAppearance:  Up to 5 feet long and 175 pounds.  Bigger than a coyote.

Diet:  Carnivore.

Lifespan:  Up to 8 years.

When Active:  Daytime.

Fun Facts:  They live and hunt in packs.  When they have killed an animal they can eat a huge amount of food at one time – up to 20 pounds.