Tentacle

In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates.

Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats.

They take the form of highly mobile muscular hydrostats with various appendages such as suction disks and sometimes thorny hooks.

[3] These tentacles are made of stalks of axial nerve cords that are covered by circular transverse muscle tissue that contract in response to stimuli.

There is a layer of helical muscle that helps each tentacle to twist or turn in any direction where the prey is sensed.

[1] The modern convention, however, is to speak of appendages as "tentacles" when they have relatively thin "peduncles" or "stalks" with "clubs" at their tips.

The colloblasts burst open when prey comes in contact with the tentacle, releasing sticky threads that secure the food.

[8] The legless amphibians called caecilians have two short tentacles, one on each side of the head, between their eyes and nostrils.

The current opinion is that these tentacles supplement the normal sense of smell, possibly for navigation and to locate prey underground.

[2] The star-nosed mole, Condylura cristata, of North America, has 22 short but conspicuous tentacles around its nose.

They are mobile and extremely sensitive, helping the animal to find its way about the burrow and detect prey.