We all know that fish live in the water, but did you know that there are a lot of other creatures that live in the water too? Like arthropods, mammals, and mollusks. And don’t forget the birds that rely on water to survive!
Today, we’re diving deep into the world of the other water animals.
Arthropods are invertebrate animals with exoskeletons (or outside skeletons), segmented bodies, and jointed legs.
Lobsters, crabs, insects, and spiders are all arthropods.
Let’s start with insects. You might think of insects flying around the park or getting into your food at a picnic, but many live on or near the surface of the water. Some insects also lay their eggs in the water.
See how this water strider walks on the water?
Insects like this can walk on the water because of three things: small size, water-repellent hairs on their feet and legs, and surface tension.
Water molecules at the surface of the water “stick” together, much more so than the water molecules beneath the surface. This creates surface tension, which means that the water acts like it has skin on the surface. There isn’t really skin on the water, but it does take a lot more force to break through the surface of water than to move around under the surface.
Since water striders are so light-weight and have those special hairs, their feet don’t get went when they stand on the water. This means that they don’t sink, allowing them to stand and walk across the surface of the water.
A fun water stream insect activity:
Christine Elder, a science educator and visual artist, has great coloring pages on her site, like this stream insects coloring page. Christine’s passion is helping grown-ups and kids connect with nature. Her site is full of videos and stories about nature, her travels around the world, and tips on nature sketching.
We had a great time coloring her insects coloring page.
Crabs, lobsters, shrimp, and barnacles are all crustaceans.
Even though they all look different, they share a few characteristics like a hard exoskeleton (or shell), segmented bodies, and jointed legs. When they outgrow their exoskeleton, they need to shed it.
The hermit crab is a little different from other crabs. It cannot make its own shell, so it needs to find shells to protect its body. When it outgrows its shell, it moves in to a bigger one.
Fun crustacean fact:
Did you know that the roly poly is also a crustacean? (but it doesn’t live in the water!)
Maybe you already knew that lobsters and crabs live in the water, but did you know that some spiders do, too?
The water spider, also known as the diving bell spider, is a special spider that lives almost it’s entire life in the water. The diving bell spider doesn’t need gills like a fish, it creates underwater air bubbles where it can catch a breathe, eat, and raise its babies.
A mammal is a warm-blooded animal that has hair, has live babies (not eggs), and feeds its babies milk. You are mammal!
There are mammals like dolphins, whales, and manatees that only live in the water.
Mammals like whales and dolphins need to breathe just like you do when they swim. They have to come to the surface to take a breath and then hold their breath when they’re under water.
Just one of the big differences between you and a whale or dolphin is that they don’t breathe through their mouth or nose. They don’t even have nostrils! They breathe through a blowhole on the top of their head.
Like this one:
There’s a lot to learn about whales, like this beluga whale:
Some baleen whales, like the humpback and blue whale, are known for their unique singing.
A baleen whale is one with special bristles in its mouth instead of teeth to help them skim food from the water. Even though they grow to be very big, these whales eat small things like small fish and plankton.
Listen to these whales sing:
The manatee is another marine animal. Manatees also come to the surface to breathe. When they come to the surface, they take a big breath through their nose before going back underwater.
Birds are warm-blooded animals with feathers, wings, beaks. They lay eggs.
Even though birds don’t live entirely in the water, many of them are very good swimmers. Think of ducks, penguins, and geese.
To get a look at water birds in action, just look at these penguins go!
Other aquatic birds need the water to live, like the pelican and flamingo.
Flamingos are well known for their bright pink or orange feathers, but did you know that they are born with grey feathers? Flamingos turn pink over time due to the pink and orange pigments, called carotenoids, in the food they eat. If they didn’t have these pigments in their diet, they would be white or a very pale, faded pink.
Sometimes flamingos gather in very, very large groups for feeding and mating.
A mollusk is an animal with no backbone (or an invertebrate). It has a soft body, lives in a wet environment, and often has a hard shell.
Snails, clams, and oysters are all mollusks. So are cephalopods like the squid and octopus.
Aquatic snails are a special kind of snail that live in the water. It’s important to keep in mind that not all snails can live in the water! They breathe through gills or special lungs.
An octopus is also a mollusk, even though it looks very different from snails, clams, and oysters. The octopus does not have a shell.
Did you know that an octopus camouflages itself by changing colors?
It can also defend itself by releasing ink to distract a predator while it makes a quick getaway.
Phew, that’s a lot of water animals, and that’s only the beginning!
What’s your favorite animal that lives in the water?
Want to keep the innovation going? Join Rosie on her imaginative adventure in building a robot in the free digital picture book, How to Build a Robot from A to Z.