Alaska marmots wake every three or four weeks during hibernation mainly to do what?

Alaska marmots wake every three or four weeks during hibernation mainly to urinate and defecate.

This is an unusual interruption of an otherwise remarkably deep winter sleep. Alaska marmots remain inside communal winter dens from roughly September until early May, while their body temperature, heart rate and breathing rate fall sharply to conserve energy.

The den is sealed with soil, vegetation and feces, helping the colony endure Arctic conditions. Marmots also tolerate unusually high carbon dioxide and low oxygen levels inside the enclosed hibernaculum. Periodic arousals allow them to eliminate waste rather than soil the central sleeping area.

This should not be confused with waking to hunt or drink: Alaska marmots do not forage during these brief winter arousals. Their hibernation is also communal, with family groups sharing a den, a strategy thought to reduce heat loss and metabolic costs in the far north.