Tentacle

Tentacle

A Tentacle is a flexible, mobile, elongated organ present in some species of animals, particularly invertebrates. Tentacles are used in various ways depending on the creature's lifestyle: feeding, feeling, grasping, locomotion, and/or reproduction.

Anatomy

Tentacles are elongated, flexible growths, sometimes hollow and filled with fluid. While they are primarily used for feeding, they can also be used for sensing the environment, locomotion, or for the capture and manipulation of objects.

Invertebrates

In invertebrates, tentacles are usually provided with suckers or adhesive organs, and often with the power of active movement. They are found especially among cephalopods and cnidarians.

Cephalopods

In cephalopods, tentacles are a form of muscular hydrostat. Most cephalopods possess tentacles for catching prey, with squid and cuttlefish bearing eight arms and two tentacles, and octopus species equipped with numerous sucker-bearing arms.

Cnidarians

In cnidarians, tentacles are armed with specialized cells called cnidocytes, which contain organelles called nematocysts. These are used to capture prey and as a means of defense.

Vertebrates

In vertebrates, the term "tentacle" is often applied to various elongated flexible organs such as the elephant's trunk and the tapeworm's scolex, which are not true tentacles as they are present in invertebrates.

See also

• Arm (anatomy)
• Cephalopod limb
• Cirrus (biology)
• Pseudopodium