Animal Group

Invertebrate Facts For Kids

Invertebrates are animals that have NO backbone! They include insects, spiders, octopuses, crabs, jellyfish, and many more. In fact, more than 95% of all animals on Earth are invertebrates. They live everywhere from deep oceans to your backyard!

Quick Invertebrate Facts

How many kinds?: Over 1 million known species (most animals on Earth!)
Body covering: Many wear exoskeletons (hard outsides) like a suit of armor
Body temperature: Cold-blooded
Babies: Most lay eggs; many change shape as they grow
Breathing: Through gills, lungs, or tiny holes in their bodies
Smallest: Microscopic, smaller than a grain of sand
Largest: Colossal squid, over 40 feet long

Insects: The Six-Legged Wonders

Insects have six legs, three body parts, and most have wings. There are more insects than any other kind of animal! From hardworking ants to beautiful butterflies, insects are everywhere.

Featured animals: Butterflies, Bees, Ants, Ladybugs, Beetles, Dragonflies

Arachnids: The Eight-Legged Hunters

Arachnids have eight legs and two body parts. They include spiders, scorpions, and ticks. Most arachnids are predators that eat insects. Spiders spin amazing webs to catch their food!

Featured animals: Spiders, Tarantulas, Scorpions

Mollusks: The Soft-Bodied Animals

Mollusks have soft bodies, and many wear shells to protect themselves. Snails and clams are mollusks. So are super-smart octopuses and squids! Octopuses can solve puzzles and even open jars.

Featured animals: Octopuses, Squids, Snails, Clams

Crustaceans: The Underwater Armor-Wearers

Crustaceans wear hard shells and have many legs. Most live in water. Crabs, lobsters, and shrimp are crustaceans. They grow by shedding their old shells and growing new ones.

Featured animals: Crabs, Lobsters, Shrimp

Other Amazing Invertebrates

Jellyfish drift in the ocean using stinging tentacles. Sea stars have five arms and can grow back any arm they lose. Worms tunnel through soil, keeping it healthy for plants.

Featured animals: Jellyfish, Sea Stars, Worms

Cool Facts About Invertebrates!

Octopuses have three hearts! Two hearts pump blood to the gills, and one pumps blood to the rest of the body.
Spiders eat their own webs! Spiders eat their old webs to recycle the silk, then spin new ones.
A jellyfish has no brain! Jellyfish have no brain, no heart, and no bones, yet they have drifted through the oceans since long, long ago.
Ants can carry 50 times their weight! If you were as strong as an ant, you could lift a car over your head.
Bees do a dance to give directions! When a worker bee finds flowers, it dances in a special way to tell the other bees exactly where to find them.

Invertebrate Questions Kids Ask

What does invertebrate mean?

An invertebrate is an animal without a backbone. Animals with backbones like us, dogs, fish, and birds are called vertebrates. Most animals on Earth are invertebrates!

Are spiders insects?

No! Spiders are arachnids, not insects. Insects have six legs and three body parts. Spiders have eight legs and only two body parts. Spiders are more closely related to scorpions than to butterflies.

How can a body work without a backbone?

Invertebrates have different ways to support their bodies. Some wear hard exoskeletons like armor. Others have fluid-filled bodies that hold their shape. Some, like worms, just use strong muscles.

Are octopuses really smart?

Yes! Octopuses are some of the smartest invertebrates. They can solve puzzles, open jars, escape from tanks, and even use tools like coconut shells for shelter.

Why are bees important?

Bees pollinate flowers, which helps plants make fruits, vegetables, and seeds. Without bees, we would have much less food. Bees are some of the most important animals on Earth!