Sea otters hold hands to protect themselves while sleeping. Since sea otters float on top of the water, they are at risk of drifting away from their groups, so while they sleep, the otters typically hold each other’s paws to keep from becoming separated. These groups of sea otters are referred to as rafts and can consist of just a few or as many as 100 otters. During the daytime, sea otters often tie themselves with sea plants growing on the ocean floor to anchor themselves so they don't float away. They generally do this when lying on their backs and using rocks to crack open mussels or clam shells to eat.
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