Dancing Shrimp (Rhynchocinetes durbanensis), Indonesia. Lars Hallström / age fotostock / Getty Images

Arthropods are animals in the Phylum Arthropoda, a very diverse group of organisms that includes insects, crabs, lobsters, scorpions, and centipedes.

Characteristics of Arthropods:

All arthropods have:

  • Jointed legs, making them quick-moving organisms
  • A segmented body
  • A hard exoskeleton made of a strong polysaccharide called chitin. This hard "shell" helps protect the animal and retains moisture.


Habitat and Distribution:

Arthropods are found in habitats all over the world - dry land, fresh water, and salt water. In the ocean, they can live from coastal habitats like sandy beaches and intertidal areas all the way to the deep sea.


Most arthropods reproduce sexually, through internal fertilization. In many arthropods, such as crabs, you can see eggs attached to the abdomen.

Marine Examples of Arthropods:

Examples of marine arthropods: