Hermit Crab
All About Crabs
From tiny water fleas to large lobsters – crustaceans are true all-rounders and can be found in many habitats!
What Are Crustaceans?
Crustaceans are invertebrate animals. This group includes crabs, shrimp, lobsters, and woodlice. Most species live in the sea or freshwater, but some have adapted to life on land. In total, there are thousands of species with a wide variety of shapes and sizes.
Main Characteristics of Crustaceans
1. Hard Shell
Crustaceans have an exoskeleton made of a horn-like material called chitin and calcium. This exoskeleton is very hard, providing protection against predators. They grow throughout their lives, shedding their old, too-small shell to allow a new one to grow.
2. Ten Legs and two Claws
Most crustaceans have ten legs, which are paired. They have five legs on each side. In some species, the first two legs are transformed into claws. These claws help them defend themselves, hold onto prey, and communicate with their fellow species.
3. Two Pairs of Antennae
All crustaceans have two pairs of antennae, which means they have a total of four. One pair is often really long – like in the case of lobsters. They use them to sense their environment.
Crustaceans Family Tree
Amazing Facts About Crustacanes
- There are 67,000 species of crustaceans.
- The most well-known are pistol shrimp, cleaner shrimp, coconut crab, hermit crab, mantis shrimp, water flea, barnacle, fiddler crab, brown crab, lobster, and spiny lobster.
- The body structure of crustaceans is so varied that they share only a few common features.
- All crustaceans breathe using gills.
- Most crustaceans live in the sea. However, there are also species that occasionally come ashore and burrow into the wet sand. Terrestrial hermit crabs and woodlice live exclusively on land.
- Crustaceans are omnivores. They mainly eat fish, shellfish, sea urchins, and other crustaceans. They also consume algae and plankton.
- The largest land-dwelling crustacean is the coconut crab. It is a terrestrial hermit crab. It can grow up to 15 inches (40 cm) in body length, have a wingspan of up to 39 inches (1 meter), and weigh as much as 9 pounds (4 kg).
- The fastest crustacean in the water is Henslow's swimming crab. It can reach a speed of 4.2 feet (1.3 meters) per second. That translates to approximately 2.8 mph (4.6 km/h).
- The fastest crab on land is the ghost crab. It can reach speeds of 13 feet (4 meters) per second. That translates to about 8.6 mph (14 km/h).
