Crustacean -

While they vary immensely in shape and behavior, most crustaceans share several defining biological traits:

: Tiny but essential links in the marine food web, supporting massive animals like whales.

: Because their shells are rigid, crustaceans must periodically shed and regrow them to accommodate growth. crustacean

: A few groups have adapted to life on land, including woodlice (sowbugs/pillbugs) and certain land crabs, though they still require damp environments to breathe through their gills. Common Examples

Crustaceans are primarily , found in nearly every marine and freshwater environment on Earth. While they vary immensely in shape and behavior,

The most well-known crustaceans belong to the order , characterized by five pairs of legs:

: Their bodies are usually segmented, often featuring a cephalothorax (a fused head and trunk). Diverse Habitats and Ecological Roles Common Examples Crustaceans are primarily , found in

: Species like crayfish are common in rivers and lakes.