Whales, dolphins, otters, walruses, and orcas are just like us, they’re mammals. Well, they’re not just like us. They live in the ocean. They breathe air, have hair, nurse their babies, and they are warm-blooded. They keep the same body temperature all day. To do that in the ocean isn’t easy. Water soaks up heat, so the ocean is really pretty cold. Marine mammals have all sorts of ways to keep warm. Whales, dolphins, and walruses have thick layers of fat called “blubber.” It’s great insulation. It holds their body heat keeping them warm in the cold ocean. Sea otters have thick layers of fur that cover their whole bodies. Otters fluff their fur to trap air between the hairs. It helps them float, it the air keeps them warm even when they dive deep hunting for food. These adaptations make it possible for marine mammals to live all over the world’s oceans.