Is a Crab a Carnivore or an Omnivore?

Like most humans, crabs are omnivores. This means that they eat both plants and animals. That does not mean that a crab's diet is similar to a human's. The most common feature of a crab's diet is algae, a photosynthetic plant that occurs in many different forms, from single-cellular organisms to large kelp. Since crabs are omnivorous, their diets vary based on the environment around them. Some feed on coral, others on dead animals. Crab diets also vary depending on species.

  1. Algae and Other Plants

    • Algae comprises a large part of a crab's diet. This is partly because it is so ubiquitous in most crab habitats. Kelp, for example, is abundantly common in most saltwater locations where crabs are plentiful. There also several species of live plants that appear in crab habitats that crabs will sometimes eat.

    Worms, And Other Sea Animals

    • Some crabs, like the Dungeness crab, eat worms, starfish and sometimes small fish. The snow crab, for example, eats worms, and also eats small fish that appear in the sea. Crabs usually eat these creatures after they are adults, and subsist on plants and algaes in their first few weeks.

    Other Crabs and Detritus

    • Blue crabs, among other species, sometimes eat other crabs. Sometimes they will catch the other crab and eat it alive, while at other times they will eat dead crabs. In addition to other crabs, crabs feed on several kinds of detritus, from floating fish parts to snails. This diversity of diet allows crabs to live in several different climates.

    Conclusion

    • Crabs are omnivores with a remarkably diverse palette of food. Crab diets are strongly related to their immediate environment, in part because they are so versatile and can feed on just about anything, from fish, worms, and other crabs to algae and plants. This versatility is a testament to the diversity of the oceans as an ecosystem.