Feather stars are a type of marine invertebrate with featherlike arms that radiate from a central body. They date back about 200 million years, says Tomasz K. Baumiller, a professor of paleontology at the University of Michigan.
“Feather stars are thought of as living fossils,” Baumiller says. “They have a tremendous diversity that traces its roots deep down in the geological past.”
These animals inhabit a broad geographical range, from the Equator to the poles, and from the shallow waters on top of reefs to the depths of the ocean. In particular, the western edge of the Pacific around Asia is a “cradle of diversity” for feather stars, Baumiller adds.
Not all feather stars can swim. Many species are only able to crawl along the bottom. There are a few theories about the reason behind the swimming adaptation, including to escape from predators or to more easily relocate.
Regardless, their movement through the water is captivating.
Feather stars can be a variety of spectacular colors, from deep reds to vibrant oranges and electrifying yellows. Each arm can be up to a foot long.
Born with a stem that they shed in adulthood, feather stars can have as few as five arms and as many as 200. Their appendages are used to catch food, making these animals filter feeders. They sit in the water, expose their arms, and let nutrients moved by the current come to them, a characteristic that makes them quite conspicuous to divers and snorkelers.
Feather stars also have the ability to shed an arm the way some lizards can their tails, which is also likely an anti-predator response. Some feather stars are also toxic, helping them avoid getting eaten. But because small animals like snails often live on them, fish may comb through feather stars looking for a tasty meal.