Sperm whale pod surfacing, Dominica

© Franco Banfi/Minden Picture

Taking a breather. Sperm whale pod surfacing

Ahoy there, giants of the sea! The planet's 92 whale species are split between baleen whales and toothed whales. Baleen whales use bristle-like mouth parts to filter krill from the water. The sperm whales pictured here, like the other 76 toothed species, use cone-shaped teeth to attack their prey. Unlike baleen whales, they hunt and navigate using echolocation, a method that uses sound to detect the things around them. Sperm whales also happen to have the largest brain of any animal on Earth! A whale's large brain-to-body mass ratio means that their intelligence is no fluke.