copula - an equating verb (such as `be' or `become') that links the subject with the complement of a sentence. copulative, linking verb. verb - a content word that denotes an action, occurrence, or state of existence.
Different species of crabs eat different foods. Depending on the species, they may eat plankton, worms, shrimps, prawns and other shellfish, and they scavenge for animal and/or plant remains. 1  They are detrivores. 2  They will consume animal as well as plant matter (algae, etc.).
Crabs are 'carrion eaters', meaning they feast on what's left after a larger predator has its fill. Typically, they munch on pieces of dead fish or whatever else happens to wind up on the bay or ocean bottom, since that is where they live.