What are Invertebrates?

Did you know that some animals don’t have a backbone? A backbone is a line of bones that runs down our back and helps us stand up tall and strong. But not all animals need one! The animals that don’t have a backbone are called invertebrates.

Invertebrates can be very small, like tiny beetles, or a bigger, like jellyfish and octopus. Instead of a skeleton made of bones, many invertebrates have a hard outer shell or exoskeleton that protects their soft insides. This shell can be found on animals like crabs, insects, and spiders. Other invertebrates, like jellyfish and worms, have soft bodies that can bend and move easily. Even without bones, invertebrates are strong and can do many amazing things! They crawl, fly, swim, and live in all kinds of places. Let’s learn more about these incredible animals and the different types of invertebrates we can find around us!

Comparing Vertebrates and Invertebrates
Types of Invertebrates
Where Do Invertebrates Live?
How Do Invertebrates Move?
Fun Facts About Invertebrates
Look for Invertebrates Around You
Resources for Learning About Invertebrates
- Available in HOKA

Comparing Vertebrates and Invertebrates

Video: Fun Science Demos

Vertebrates and invertebrates are both groups of animals, but they have one big difference: vertebrates have a backbone, while invertebrates do not. A backbone is a set of bones that runs along the middle of an animal’s back and helps it stay strong and upright. Animals like dogs, birds, and fish are vertebrates because they have backbones. On the other hand, animals like worms, insects, and jellyfish are invertebrates because they don’t have a backbone. Even though they are different in this way, both vertebrates and invertebrates can move, eat, and live in many different places around the world.

Types of Invertebrates

Video: MooMooMath and Science

Here are some common invertebrates you may have seen or heard of!

Insects: Insects are the largest group of invertebrates. They have three main body parts: the head, thorax, and abdomen. Insects also have six legs and often have wings. Examples of insects are butterflies, ants, and bees.
Arachnids: Arachnids are invertebrates that have eight legs. Unlike insects, they don’t have wings or antennae. Spiders and scorpions are common examples of arachnids.
Mollusks: Mollusks are soft-bodied invertebrates, and many of them have shells for protection. Snails, clams, and octopuses are all mollusks. Some live on land, like garden snails, while others live in water, like squids.
Crustaceans: Crustaceans are invertebrates that usually live in water and have a hard shell and multiple pairs of legs. Crabs, lobsters, and shrimp are all crustaceans. They have a special shell called an exoskeleton that protects their soft bodies.
Worms: Worms are long, soft-bodied invertebrates that live in many different environments. Earthworms live in the soil, while some worms, like tapeworms, live inside other animals.
Cnidarians: Cnidarians are invertebrates that usually live in the ocean and have soft, jelly-like bodies. Jellyfish and sea anemones are examples of cnidarians. They often have tentacles that can sting.

Where Do Invertebrates Live?

Invertebrates can live almost anywhere in the world! They are very adaptable and can be found in many different environments.

On Land: Many invertebrates live on land, like insects and spiders. You can find them in gardens, forests, fields, and even in your own backyard. Ants build their homes underground, while spiders spin their webs in trees and corners of buildings.
In Water: Some invertebrates live in water. Crustaceans like crabs and lobsters live in the ocean, while freshwater snails can be found in ponds and rivers. Jellyfish and octopuses are also invertebrates that live in the ocean.
Underground: Worms and other invertebrates like to live underground, where it’s dark and damp. Earthworms, for example, help make the soil healthy by breaking down dead plants.
In the Air: Insects like bees and butterflies are invertebrates that can fly. They move from place to place in search of food and flowers.

Invertebrates are everywhere, from the tops of trees to the depths of the ocean. No matter where you go, you’re likely to find some kind of invertebrate living nearby!

How Do Invertebrates Move?

Invertebrates move in many different ways, depending on their bodies and where they live. Let’s explore how some of them get around:

Crawling and Slithering: Many invertebrates, like worms and snails, move by crawling or slithering along the ground. Worms use their muscles to stretch and squeeze their bodies, while snails glide slowly on a slippery trail of mucus.
Walking: Insects, spiders, and other arthropods have legs that help them walk. Insects like ants have six legs, while spiders have eight. They can move quickly or slowly, depending on what they need to do.
Flying: Some invertebrates, like butterflies, bees, and dragonflies, have wings that let them fly. They use their wings to travel from one place to another, looking for food or finding new homes.
Swimming: Invertebrates that live in water, like jellyfish, octopuses, and crabs, often swim to get around. Jellyfish drift through the water by pulsing their bodies, while octopuses use their arms to push themselves along. Crabs use their legs to walk on the ocean floor or swim short distances.
Jumping: Some invertebrates, like grasshoppers and fleas, can jump very high or far. They use their strong legs to leap quickly, which helps them escape from danger or move to a new spot.

Each invertebrate has a special way of moving that helps it survive in its environment. Whether they’re crawling, flying, or swimming, invertebrates are always on the move!

Fun Facts About Invertebrates

Invertebrates are amazing creatures, and there are so many fun things to learn about them! Here are some cool facts:

Butterflies Taste with Their Feet: Butterflies don’t use their mouths to taste things like we do. Instead, they use their feet! When a butterfly lands on a flower, it can taste the nectar with tiny sensors on its feet.
Octopuses Have Three Hearts: Did you know that an octopus has three hearts? Two hearts pump blood to the gills, and the third heart pumps blood to the rest of the body. This helps the octopus stay strong while swimming.
Ants Are Super Strong: Even though ants are tiny, they are incredibly strong! Some ants can lift things that are 50 times heavier than their own body weight. That’s like you being able to lift a car!
Jellyfish Glow in the Dark: Some jellyfish can glow in the dark, a special ability called bioluminescence. They light up to attract prey or scare away predators.
Spiders Spin Silky Webs: Spiders create their webs using silk that comes from their bodies. This silk is strong and sticky, perfect for catching insects. Some spider silk is even stronger than steel!
Crabs Can Walk Sideways: Crabs have a funny way of walking—they move sideways! This helps them move quickly and escape from predators while keeping their strong claws ready to defend themselves.
Earthworms Help Plants Grow: Earthworms are like little gardeners. They eat dead leaves and other plant material in the soil, breaking it down into nutrients that help plants grow. They also dig tunnels that help water and air reach plant roots.
Bees Dance to Communicate: When bees find a good source of food, they do a special dance called the “waggle dance” to tell other bees where to go. The direction and length of the dance show the location of the flowers.

Invertebrates might be small, but they have big talents and amazing abilities that make them special!

Look for Invertebrates Around You

Invertebrates are all around us, in the soil, the air, the water, and even in our own backyards. They might be small, but they play important roles in nature. Now that you know more about these amazing animals, you can start looking for them wherever you go. Whether it’s a butterfly fluttering by or a worm wiggling in the dirt, there’s always something new and exciting to discover about invertebrates!