One of the most bizarre yet fascinating creatures in the ocean are the tentacles. Sometimes it can be very hard to determine what a tentacle really looks like. Most people refer to it as an "oceanic clownfish", but since the actual name is quite vague, it is often left up to the viewer to come to a conclusion about its appearance. In actuality, the tentacle does not have a "face", but there are several distinct characteristics that help to classify this peculiar looking sea creature. Tentacles are not normally visible to the human eye, even though they tend to move about under the water in clusters.
Tentacles are known to be present in a number of different animal groups. They are present in the phylum Cnidaria (sea-worms) and are part of the siphonophore family. It is not entirely clear how these creatures come into existence, but the most common hypothesis is that they were once creatures of the ocean's bottom layers. As a result, the basic form of their anatomy is the same as that of fishes and other invertebrates: a thin, rigid tube with several mouthfuls at the opening.
The true external appearance of the tentacles, however, has been a mystery for many years. Physiological features, including the fact that most tentacles are simply soft-shelled discs, led some researchers to conclude that they must be fed by some type of food. For many years, the exact function of tentacles was a subject of great debate.
Recently, efforts have been made to find out more about the behavior and lifestyle of tentacles. Tentacles are actually capable of swimming through the ocean, although their rate of movement is slow. They usually stay near the bottom of the ocean, feeding on small crustaceans, tiny bivalves, algae, and various forms of bacteria. Some tentacles have even been discovered alive. However, because these animals are not closely related to any living being on Earth, their exact relation to humans remains uncertain.
Some current theories suggest that the development of tentacles may have originated in the ocean's early evolution. Another possibility is that the animal first emerged from its natural habitat on Earth through an accidental, symbiotic relationship with another terrestrial animal. Perhaps, the earliest of the tentacles ever found were the ones that wrapped themselves around the pre-existing arthropods that already existed on Earth.
Today, it is very difficult to say anything about the exact relationship between tentacles and the animal kingdom. In fact, the scientific community has never been able to identify a single tentacle that belongs to any specific group of organisms. There are, however, certain types of tentacles that tend to look a lot like the animal that they wrap around. Thus, it is possible to conclude that all tentacles belong to a class that includes smooth oval body with smooth legs and three to four pairs of proteinuric tentacles (where the name comes from).