When digging their burrow, marmots take the excavated dirt out of the hole. This pile of excavated dirt is called a hillock. The burrow is repaired every year, and additional dirt is removed, so the hillock gets bigger and bigger year after year. The hillocks of the hibernation and summer burrows are usually not that big. Sometimes the hillocks of burrows with many entrances or several adjacent burrows will combine to create an extra-large hillock. The hillocks of burrows located on the slopes of mountains were lower, and were shaped like an ellipse. The hillocks of burrows located on flat landscapes had a round shape, and the downhill side was the tallest, usually with a height of up to 1.3m.
