Sea stars are invertebrates of Phylum Echinodermata (lit. trans. ‘Echino-skin-a’), comprising roughly 1,800 and many more rising stars that have yet to be discovered by Science’s talent scouts. They are also known as star fish, though using that term became a bit awkward after someone pointed out that they’re not fish.
Who was calling this a fish again? You’re fired.
Physically, most sea stars have five tapered appendages pointing out from a center mass, and thus do, in fact, resemble stars. This fact gives sea stars sufficient cover to adopt one of the most self-congratulatory names of any animal, terrestrial or marine.
Didn’t you see my name? Q.E.D., dude.
Sea stars are noted for their two stomachs, one for digestion and one for engulfing and digesting food outside the body, giving the sea star a disgusting something in common with their echinoderm brother, the sea cucumber. Sea stars also feature a ringed water vascular system, which is used for food and waste transportation, respiration, locomotion, and innumerable mind-bendingly boring freshman bio lectures. The water vascular system also provides the hydraulic force for the sea star’s tube feet, which resemble tiny suction cups and are used to eat and move about as slowly as you can possibly imagine.
Whereas most animals (humans included) are bilaterally symmetrical, sea stars are one of a special group of those who exhibit radial symmetry. In other words, they do not have left or right sides, but simply a top and bottom. So enjoy making conversation at the sea floor office party.
Why are you staring at my shoulder?
Perhaps you have heard that sea stars can regenerate lost appendages. So have we. So has everyone. Perhaps you have also heard that Coca-Cola used to have cocaine in it. And Eskimos have a hundred words for snow. Way to go.1 What’s important is that before this Lazarus-like ability of sea stars was understood, fishermen doubled their problems when, in an attempt to get rid of sea stars (who competed unfairly for the same prey), they cut them in half and, disgusted by what they had done, tossed them back into the ocean, only to find themselves facing twice as many now-angry sea stars later on.
In addition to being able to regenerate lost body parts and bore high schoolers, sea stars also have the ability to be a keystone species. In the North American Pacific coastline, sea stars eat mussels, keeping their population in check and preventing the mussels from crowding out other species. This serves to protect biodiversity and reminds us that everyone, no matter how small, has an important role to play. And Eskimos have a ton of words for snow.
1 According to linguist Steven Pinker in his book The Language Instinct, the stuff about the Eskimo and the words for snow really isn’t true at all. Generously speaking, he comes up with no more than a dozen. But the Coca-Cola thing with the cocaine is true. But keep in mind, back when Coca-Cola was invented, you could buy cocaine from policemen to treat hangovers.