Swimming Critters: Vertebrates

There are 28 main types of animals, or phylla. Only one type of animal, the sub-phyllum "Vertebrates", has a spine like ours. In other words, we are more closely related to an ordinary fish than that fish is to a starfish or jellyfish.

All vertebrates have a spine down the middle, and the left side looks like the right side. This is called "mirror symmetry" or "bilateral symmetry". So you'll never see a vertebrate with 5 arms (like a starfish), or 8 arms (like an octopus), or a lot of tentacles (like a jellyfish). Vertebrates don't move like those animals either.

Shark with Fish, and Robo-fish

Sharks are fish. Like all fish, they wag their tails side-to-side to swim.

Dolphin and Humpback Whale

Dolphins and whales are mammals. They swim by waving their tails up and down

Sea Lion and Sea Otter

These furry mammals have big hind feet for swimming and steering

Sea Turtle