Shrimp, crab, crayfish, and lobsters are all crustaceans. In Japan, the giant spider crab grows to 12 feet when measured between the outstretched limbs.
Most of the 30,000 species of crustaceans live in salt water, but some live in fresh water.Some live on land.
The bodies of crustaceans have 3 parts: the head, the thorax, and the abdomen. Crustaceanshave 2 sets of antennae and 6 to 14 pairs of legs. Crustaceans havecompound eyes. Crustaceans have small brains.
Crustaceans are essential to aquatic ecosystems because they feed on microorganism that livein water.
