Marmots live in burrow systems underground, which they dig with their powerful front teeth and claws. A marmot burrow can be enormous — sometimes three metres deep and over ten metres long, with separate chambers for sleeping, eating and raising young. The burrow is always warm inside, even when there is snow above.
Marmots are one of Europe's largest rodents — a fully grown one can weigh as much as a cat. In autumn they eat as much as possible to build up a thick layer of fat, then they sleep through the entire winter in their burrows. This deep winter sleep is called hibernation and can last up to six months.
During hibernation a marmot's heartbeat slows down dramatically — from around 120 beats per minute to just three or four. Its body temperature drops close to freezing. When spring arrives and the mountain meadows become green again, the whole marmot family wakes up and gets very busy very quickly.
Marmot families live together in groups, with one dominant pair in each group. They are very sociable and spend a lot of time playing, grooming each other and lazing in the sun on warm rocks. If you sit very quietly in an alpine meadow, you might see one pop up from its burrow and look around.