tentacule

Tentacule is a term used in biology to describe a flexible, elongated appendage that extends from an animal’s body and is used for sensing, manipulating, and capturing prey. The word is cognate with the English tentacle and is used in several languages for similar structures. In many contexts, tentacules are found in cephalopods, cnidarians, and a variety of other invertebrates.

In cephalopods, tentacles are typically long, muscular, and capable of rapid extension. They function mainly to seize prey, often with a club-like distal end that bears suction cups or hooks. Most cephalopods also possess shorter, prehensile arms that surround the mouth and aid in handling prey and locomotion. In species such as octopuses, two specialized feeding tentacles can be extended from the head region, while squid and cuttlefish usually have a pair of long tentacles plus eight arms.

In cnidarians, such as sea anemones and jellyfish, tentacles radiate from the body around the mouth and are armed with stinging cells (cnidocytes) used for defense and prey capture. Tentacules may also be present in other invertebrate groups, sometimes as sensory or locomotor structures rather than feeding appendages.

The morphology and function of tentacules vary widely among taxa, reflecting adaptations to different feeding ecologies and environments. They are generally flexible, muscular structures, though their distribution, sensory capabilities, and mechanical design differ across species.