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Yellow-bellied marmots populate areas above treeline

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Over the years, my late husband, Bill, and I drove the highway to the summit of Mount Evans many, many times. It was one of our favorite places. We loved the high mountains, and Mount Evans was one of the good guys because he wore a white hat (of snow).


I loved the alpine botany, and Bill always looked for the nesting birds and especially for a black swift flying over. We both were impressed by the silent grandeur of the Continental Divide, and the serenity and peace in the high mountains. In some way, we both seemed to feel at home there.
I haven’t driven that road now for several years for I don’t believe the shortage of oxygen would be good for me, however in years past, there was always a large yellow-bellied marmot that claimed one of the pull offs on a switchback very near the top. She had her den beneath a large rock in the rock slide that was part of the highway construction. She whistled at every car that went by or pulled off over her burrow. She was a big old marmot that was wise in the ways of her kind and whistled a warning every time a predator came close enough to be a threat. Be it a golden eagle overhead or a car on the road, her whistle sent young marmots and other animals scurrying into their burrows.
If you were an easterner, you probably slowed down to take a good look at that “big woodchuck” for they are closely related. In fact, many people call these marmots roadchucks. They are in the same genus as the woodchuck. Their Latin name is Marmota flaviventris, which is the European name for their marmot, and flava simply means yellow and ventris is underside or belly. They don’t look for areas of deep soil to dig a burrow as woodchucks do but prefer to take over the natural tunnels formed by rock slides where they cannot be dug out.
The yellow-bellied marmot is usually bigger than the woodchucks I knew in the East, but most of the reference books I have say they are smaller. That may just be because the woodchucks in the East seldom live long enough to become full size while yellow-bellied marmots on Mount Evans in their rock burrowslive long enough to reach a large and venerable age.
The hoary marmot of the Northwest is the largest of the three and has much white and black (hoary) on the fur on its head and shoulders. The books also list the range of the yellow-bellied marmot from the foothills to above timberline. I have never seen one down this low, perhaps because all our local meadows are home to other ground squirrels.
Many books list prairie dogs in the lower foothills, which I have never seen either. The nearest prairie dog town I know of is near Chatfield Reservoir.
Marmots live almost entirely on soft, tender, new plant growth and do not consider the dry brown grasses at the end of summer fit to eat. In drought summers such as we had this year, they estivate, which means they go to sleep or into a hibernation-like state in summer when the grasses and other plants have turned brittle and dry. If we get rain and plants turn green again with new growth, they begin to feed again.
However, frost comes early at their altitude, and the grass soon turns brown again, and they go into hibernation for the long winter. They have the longest hibernation of any of the small mammals. They often are in this deep sleep-like state for more time than they are awake each year.
They are not awake on Groundhog Day and would not go back to sleep if they saw their shadow. They usually appear sometime in April but once awake, they stay awake. They mate in the early spring and have young in late spring. The young develop very quickly for they have a very short time to put on enough fat to see them through their first winter’s hibernation.
The marmot’s voice is a sharp whistle, a warning call that there is some predator in the area. Although it is sometimes described as a musical whistle, it has no melody. It sounds like a short, loud blast of a single note on a police whistle. I know that sound well for my mother had a police whistle that she blew whenever she wanted us children to come home. We roamed over more than 600 acres in the summer, but one blast on the whistle meant we were to come home, and it was not an acceptable excuse that we couldn’t hear it.
The Mount Evans road is closed this year, but do go up it next summer to look for the yellow-bellied marmots. They are an interesting part of the arctic life we find above timberline.