Mollusks Lesson for Kids

Instructor: Heather Pier

Heather has taught high school and college science courses, and has a master's degree in geography-climatology.

Come learn about an interesting group of animals called mollusks. Mollusks can be found all over the world. They can live on land and in water, and range in size from very small to very large.

What is a Mollusk?

Even if you've never have seen or heard the word 'mollusk', there is a very good chance you have seen one. If you've ever seen a snail or a slug, then you've seen a mollusk!

One of the most well known mollusks is the snail.

Mollusks are a group of animals that have a common set of body features. Snails, slugs, octopuses, clams, and oysters are all mollusks. It may seem like a snail wouldn't have much in common with an octopus, but it turns out that they do.

Mollusk Features

All mollusks are invertebrates. This means that they have no backbone, or spine. If you look at a slug, which is squishy, you can tell it doesn't have a backbone. It is actually a good thing that they don't have backbones, because it would be very hard for a snail to slide into its shell or an octopus to sneak into a tight corner if they had backbones.

All mollusks also have soft bodies. In many cases, they grow shells to help protect their soft body parts.

All mollusks also have a body part called a foot. Their foot is kind of like your foot, because it is used to help them move around. The main difference between your foot and their foot is that their foot can sometimes take up most of their body. Imagine what your life would be like if your foot went from your current foot to your neck!

Mollusks also have a special feature called a radula. Their radula is a sharp tongue-like body part that is used to scrape food off of hard surfaces and push it into their mouths.

Mollusks can be found all over the world, on land and in the water. Depending on the animal, they can be found in either freshwater or saltwater.

Clams can live in both freshwater and saltwater. This is a saltwater clam.

Types of Mollusks

There are three different types of mollusks, just like there are many different types of mammals:

  • Gastropods are the group that includes snails and slugs. These mollusks have a large foot and can live on both land and in the water.

Snails can be found on land and also in water, like this sea snail.

  • Bivalves are the group that includes clams and oysters. All bivalves have two shells, one on each side of their body, which can close up together to completely cover the body of the bivalve. Their shells closing would be like if you could close yourself up in a sleeping bag for protection. Bivalves only live in the water, but they can live in either freshwater or saltwater.

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