Crustacea facts for kids
Quick facts for kids Crustacea |
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Crustaceans are a huge group of animals that belong to the arthropod family. Think of them as cousins to insects! There are over 50,000 different kinds, or species, of crustaceans.
You might know some of them already, like crabs, lobsters, crayfish, shrimp, krill, and barnacles. These amazing creatures have been around for a very long time. We have found their fossils from way back in the Cambrian period.
Most crustaceans live in water, especially in the ocean. But some have made their homes on land. For example, some crabs and woodlice live on dry land.
Crustaceans come in all shapes and sizes. Some are super tiny, like a parasite that's only 0.1 millimeters long. Others are giant, like the Japanese spider crab. This crab can have legs that stretch up to 14 feet (4.3 meters) wide! The North Atlantic lobster can also grow very big, weighing over 40 pounds.
Most crustaceans can move around, but some become fixed in one spot after they are babies. Barnacles, for instance, attach themselves to rocks. Some crustaceans are also parasitic, meaning they live on or in other animals. Examples include fish lice.
Crustaceans usually have male and female individuals. Their eggs hatch into tiny baby forms called larvae.
Contents
What Makes a Crustacean?
Crustaceans have three main body parts: a head, a middle section called the thorax, and a tail section called the abdomen. On their head, they usually have two pairs of antennae, two eyes, and three pairs of jaws.
Most crustaceans breathe using gills, which help them take oxygen from the water. However, some land crabs have special lungs to breathe air.
Many crustaceans, like lobsters and crabs, have a hard outer shell called an exoskeleton. This shell protects them. As they grow bigger, they have to shed their old shell. This process is called molting.
Where Do They Live and How Do They Move?
Most crustaceans crawl along the bottom of rivers, streams, and the ocean. Because they live on the bottom, they are called benthic creatures.
Even though animals like lobsters and shrimps can swim, they usually prefer to walk along the seafloor.
Crustaceans and Humans
Crustaceans are very important to humans. People catch or farm millions of tons of them every year to eat. Shrimp and prawns are the most popular ones.
Tiny crustaceans like krill and copepods might not be eaten as much by humans, but they are super important in the ocean. They are a vital part of the food chain, meaning many other animals rely on them for food.
Baby Crustaceans: Larvae
Crustaceans have different stages as they grow from an egg to an adult. The earliest and most common baby form is called a nauplius.
After the nauplius stage, many crustaceans go through other baby stages. One common stage is called a zoea. This tiny creature often has spikes on its shell. These spikes might help them swim in a certain direction.
For some crustaceans, like many decapods (which include crabs and lobsters), the zoea is the first baby stage they have. Depending on the type of crustacean, the zoea stage might be followed by a mysis stage or a megalopa stage.
Images for kids
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A shed carapace of a lady crab, part of the hard exoskeleton
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Body structure of a typical crustacean – krill
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Abludomelita obtusata, an amphipod
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Eggs of Potamon fluviatile, a freshwater crab
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Zoea larva of the European lobster, Homarus gammarus
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Copepods, from Ernst Haeckel's 1904 work Kunstformen der Natur
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Decapods, from Ernst Haeckel's 1904 work Kunstformen der Natur
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Norway lobsters on sale at a Spanish market
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See also
In Spanish: Crustacea para niños
