Its brown coat darkens over the summer, starting with two black patches on the shoulders. By autumn the marmot is almost black.

Squirrels and Marmots · day 1 of 7
Black fur spreads from the shoulders until the coat is almost black in autumn.
They have four whistle types, unlike their closest relatives.
When they greet, they usually touch noses or nose to cheek.
In deep hibernation the heart can slow to three beats per minute.
Until they relearn landmarks hidden by snow, they may wander until they find their burrow.
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