Crab

Crabs are interesting animals that belong to a group of sea creatures called decapods. They have a hard shell that protects them, and their tails are hidden under their bodies. One special thing about crabs is that they can run sideways, and they often hide in rocky places in the ocean.

There are many different kinds of crabs. Some are very small, like the pea crab, which is only a few millimeters wide. Others are very large, like the Japanese spider crab, which can have legs stretching up to 4 meters (13 feet) apart! Crabs eat different things — some eat a mix of plants and animals, some only eat plants, some only eat animals, and a few even live by attaching themselves to other creatures.

People all over the world enjoy eating crabs. In Britain, a dish called dressed crab is a favorite. In places like Goa and Mozambique, people often eat crab curry. Crabs have also been important in stories and art for many years, appearing in myths, paintings, and even as a symbol in astrology. Some people keep hermit crabs as pets.

Diversity

Crabs are not just one group of animals. They include true crabs and many other groups such as hermit crabs, mole crabs, king crabs, and porcelain crabs. Even horseshoe crabs, though they look similar, are actually more related to spiders and scorpions.

Crabs come in many sizes and shapes. The smallest are just a few millimeters wide, like the pea crab. The largest, such as the Japanese spider crab, can have legs stretching over 4 meters. Some crabs live in water, while others live on land or even in freshwater. They eat different things — some eat plants, some eat small animals, and others live inside other animals and eat what they eat.

Similarity of body plan through carcinisation

Main article: Carcinisation

Most crabs are a group called the Brachyura, or "true crabs". There are about 7,000 types. Some other sea animals, like king crabs and porcelain crabs, look like crabs because they changed over time to have similar shapes and ways of living. This is called carcinisation. It shows that crabs did not all start from the same ancestor but developed similar looks in different ways.

Many crabs can move quickly sideways. Some walk forward or even swim. Crabs have a flat shell, joined body parts, and a folded tail that fits under their body.

Interactions with humans

See also: Human uses of arthropods

Fisheries and food

Crabs are an important part of the food we eat. Many people around the world enjoy eating crabs. In Western Europe, people often eat brown crabs because they taste sweet and delicate. The United Kingdom has big fisheries for this crab, especially in Scotland and the South West of England. In North America, blue crabs are caught along the Atlantic coast of the United States and in the Gulf of Mexico. In places like Goa and Mozambique, people enjoy eating crab curry. And in Japan, snow crab meat and eggs are used to make sushi.

In culture

See also: Arthropods in culture

Crabs have been important in stories, art, and myths for a long time. Both the constellation and the astrological sign called Cancer are named after the crab. Crabs have also been shown in art from ancient times. For example, people in ancient Peru often drew crabs, and famous artists like Albrecht Dürer have painted them too. There are also crab designs in clothes made by people from Panama.

One popular story for children is "The Crab that Played with the Sea" by Rudyard Kipling.

As pets

Hermit crabs are often kept as pets and used in fish tanks. One popular kind is the Caribbean hermit crab. They can live for up to 30 years if they have the right home, with sand, coconut fibre, fresh water, and salt water.

Meme

There is a funny joke that says crabs are the "ultimate forms" of life because many sea creatures have evolved to look more like crabs over time.