• Question: what is a crustacean?

    Asked by johnfraser to Zara on 23 Jun 2011.
    • Photo: Zara Gladman

      Zara Gladman answered on 23 Jun 2011:

      Hi johnfraser!

      The crustaceans are a group of animals that are usually aquatic (e.g. crabs, lobsters, crayfish, shrimp) but some are found on land (e.g. woodlice in the garden!). There are about 50,000 species that we know of. Crustaceans have a tough outer skeleton (an ‘exoskeleton’) and their bodies are divided into segments, with jointed legs. They breathe using gills to extract oxygen from water (or from air). Crustaceans hatch out of eggs and often have many life stages before they reach adulthood. In order to grow, they have to shed their exoskeleton and grow a new, bigger one.

      The biggest crustacean is probably the Japanese spider crab. We have a specimen here at Glasgow University in our zoology museum. I filmed it here: http://www.youtube.com/watch?v=zqR7g1PzPEs – let me know if your school can’t access youtube and if so, I’ll upload it somewhere else! 🙂

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