Invertebrates

An invertebrate is an animal that does not have a backbone. This includes insects, spiders, jellyfish, worms, and snails. About 97 percent of all animals are invertebrates. They come in many different shapes and sizes.

Types of Invertebrates

There are many groups of invertebrates. Arthropods include insects, spiders, and crabs. Mollusks include snails, clams, and octopuses. Cnidarians include jellyfish and coral. Worms are another large group of invertebrates.

How They Support Their Bodies

Without bones, invertebrates use other ways to support their bodies. Insects and crabs have hard outer shells called exoskeletons. Earthworms use water pressure inside their bodies to keep their shape. Jellyfish float in water, which supports their soft bodies.

Fun Facts

• The giant squid is the largest invertebrate and can be up to 43 feet long.
• Earthworms have five heart-like structures in their bodies.
• Some invertebrates, like tardigrades, can survive in outer space.

Did You Know?

Octopuses are some of the smartest invertebrates. They can solve puzzles, open jars, and even use tools!