What special adaptations do these walruses have that allow them to float on top of the water and sleep?

Walruses have large, buoyant bodies and a thick layer of blubber that provides insulation and helps them float on the surface of the water. Their muscular flippers allow for efficient movement while swimming and can also be positioned to support their weight when resting. Additionally, walruses can sleep while floating by using their tusks to anchor themselves to ice or other surfaces, allowing them to relax without fully submerging.