![]() This in turn harms all the organisms, or living things, that rely on the kelp forests. Without their natural predator, sea urchin populations are exploding and overgrazing the kelp. For example, the endangered sunflower star helped control sea urchin populations in kelp forests on the Pacific coast. The loss of any species causes a ripple effect in its habitat. This disease is made worse by rising water temperatures, like those caused by global climate change. It has affected multiple species from New England to Mexico to Alaska. A disease called sea star wasting disease has caused massive population losses since 2013. Like many marine animals, sea stars are threatened by rising ocean temperatures, ocean acidification and pollution, and other human activity. In captivity, most live 5-10 years when well cared for. On average, they can live 35 years in the wild. How long do sea stars live?Īgain, with so many species of sea stars, it’s hard to generalize lifespan. Generally, sea stars are between 4-10 inches across, but some can grow much larger. With so many species, sea stars come in a huge range of colors and sizes. The serpent sea star has long, snake-like legs that help it move faster than other sea stars. The “chocolate chips” of the chocolate chip sea star are an adaptation that warns potential predators like sharks, otters, and turtles, that this sea star will not be a tasty meal. If the torn off limb survives with any part of the central disk attached, it can grow into a whole new sea star. If they survive an attack, they are able to regenerate, or grow back, limbs that were lost. Their armor-like skin can be a range of colors to camouflage, or blend in, with their surroundings. How do sea stars protect themselves from predators?ĭepending on their habitat, sea stars have different adaptations for survival. They absorb oxygen directly from the water around them through a process called osmosis. ![]() Sea stars don’t need lungs or gills to breathe. The sea star extends its stomach out through its mouth and then pulls its food back inside. They eat mollusks like scallops, clams, and oysters, as well as sea urchins, crustaceans, and fish.Ī sea star uses its tube legs and strong muscles to pry open mollusk shells just enough for the predator’s stomach to slip inside and dissolve its prey. What do sea stars eat?īelieve it or not, sea stars are predators. At the tip of each arm is an eyespot, which can sense changes in light. Sea stars have hundreds of these tube feet on their 5 (or more) arms, which are called rays. This system includes many tube feet that act like suction cups, allowing the animal to walk, breath, and eat. They do not have brains and their vascular systems pump seawater instead of blood. Most have pentameral (or five-rayed) symmetry. By comparison, stegosaurs like Wally lived during the late Jurassic Period, 163.5 million – 100.5 million years ago.Įchinoderms are marine invertebrates (animals without a backbone) that have a skeleton of hard calcite plates. The Cambrian Period was a geological time span of 53 million years that saw an evolutionary explosion of new organisms, including our own chordate (backbone-having) ancestors. The fossil record shows that these animals have lived on earth for about 500 million years (since the Cambrian Period). Other classes include sea urchins (Echinoidea), sea cucumbers (Holothuroidea), and a huge range of living and extinct creatures. Sea stars are one class of echinoderm, Asteroidea. They are in a phylum of animals called echinoderms. What kind of animal is a sea star?Įven though they are sometimes called “starfish,” sea stars are not fish at all. The serpent sea star is indigenous to the coral reefs of the Caribbean Sea. Orange sea stars are found in seagrass meadows, sandy seafloors, and oyster beds throughout the Western Atlantic and Gulf of Mexico. They live mostly in shallow lagoons but have been discovered at depths up to 23 meters (75 feet). The chocolate chip sea star is indigenous, or naturally occurring, throughout the Indo-Pacific. Some live 9000 meters (more than 5½ miles) underwater.īerkshire Museum is home to three species, the chocolate chip sea star (Protoreaster nodosus), the orange sea star (Echinaster spinulosus), and the serpent sea star (Ophiorderma cinereum). Others live in kelp forests or coral reefs. There are about 1,600 living species of sea stars that have adapted to survive in almost every ocean habitat, even the Arctic! Some live in tidal pools or sandy seabeds.
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