Sucker (zoology)

Sucker in zoology refers to specialised attachment organ of an animal. It acts as an adhesion device in parasitic worms, cephalopods, and certain fishes and bats. It is a muscular structure for suction on the host or substrate. In parasitic worms such as annelids, flatworms and roundworms, suckers are the organs of attachment to the host tissues. In tapeworms and flukes, they are parasitic adaptation for attachment on the internal tissues of the host, such as intestines and blood vessels. In roundworms they serve as attachment between individual particularly during mating. In annelids, a sucker can be both functional mouth and locomotory organ. The structure and number of suckers are often used as basic taxonomic diagnosis between different species, since they are unique in each species. In tapeworms there are two distinct classes of suckers, namely "bothridia" for true suckers, and "bothria" for false suckers. In digenetic flukes there are oral sucker at the mouth and ventral sucker (or acetabulum) posterior to the mouth. Roundworms have their sucker just in front of the anus, hence, is often called preanal sucker.