This gentle giant can eat up to a tenth of its body weight in seagrass each day, and boat strikes are among its biggest threats since it surfaces slowly to breathe.
What defines this group — Marine mammals
Warm-blooded, they nurse their young and breathe air — the group closest to us underwater.
They breathe through a blowhole (whales, dolphins) or nostrils (seals, sea lions).
A thick layer of blubber, rather than fur, insulates them from the cold.
Many navigate and hunt by sound, using echolocation.