Watchin’ Varmints: Yellow-Bellied Marmot Behavior

While I was up on Mount Blue Sky this summer, one of my favorite pastimes was marmot watching. And this summer I got a lot of marmot watching in. No thats not a weird euphemism! I really watched marmots this summer. But before we dig in on some fun behavior…

You Might be Wondering…

What is a Yellow-Bellied Marmot?

Yellow bellied marmot, rockchuck, and whistle-pig are some of the names you’ll hear these animals called. They are essentially a really big ground squirrel. They range from about 3 to 11 lbs full grown and males are longer and weigh more than females.

They are found in the western US & Canada. In Colorado they are found at 5,400 ft up to 14,000 ft. In other places like Eastern Washington they are found at much lower levels.

They are herbivores, eating herbaceous plants and grasses. They will also find room in their diet for grains, fruit, legumes (bean family) and the occasional insect.

In Colorado, yellow-bellied marmots can spend up to 8 months of the year hibernating. Needless to say, they spend their summers eating as much as they can so they have fat to burn while they are sleeping the winter away.

They make a variety of different noises including a “chuck” sound, a whistle-like chirp, and a scream. When I hear them I always think they sound like a mutant bird.


Marmots “kiss”, and it’s considered a bonding activity. This behavior is usually with a pup or between a pair of bonded adults. In the picture below we see a pup (left) and an adult (right). It happened very quickly and I was happy I got to see this!

Territorial Behavior

A marmot perched on a rock sunning, is normal behavior. They will do this alone or with members of their colony. If a marmot intrudes that is not a member of their colony he is given hostile treatment in the form of posturing, chasing and sometimes fighting.

I got a chance to witness this in the field, when I saw a male marmot sneak into a burrow. I immediately heard crazy growling. It intensified and then the marmot burst out of the hole with another full grown marmot going full bore after it. They chased each other down into a small rocky field where they began to fight. Both of them stood up on their hind legs and tussled like angry wrestlers. Their aggro dance lasted just a few minutes before the smaller of the two ran off. Leaving the colony to go back and perch on a rock in the sun.


The next day, while on a hike down to Chicago Lakes from Summit Lake. I noticed a marmot on a rock, doing what they do best… not much. It saw me and started running after me on the path like a puppy, and when I stopped it got fairly close and stood up on its hind legs like it was begging. When it realized that I didn’t have anything to give it, it turned around and ran back to its rock.

Somebody must have fed it in the past, and as you probably guessed, feeding marmots is bad form. They have specialized diets based on the flora around them, things like granola bars and chips will make them sick.

To Wrap it Up

It’s always a gift when you can spend time in an animal’s habitat and watch them interact. I hope to see more interesting behavior next year after their 8 month nap!

And at that… I’ll leave you with this, courtesy of the internet.


Marmota Flaviventris

Rocky Mountain National Park – Marmot

National Park Service – Jewel Cave – Marmot

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Heather Valey is an award winning conservation photographer, writer and passionate naturalist. For information on licensing images please reach out to Heather via email- Heather's photography site is:

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