Specialized Characteristics of Forbes' Sea Star

Digestion

• Forbes' sea stars are carnivores that digest their food outside of their bodies. When the sea star has obtained its prey, it forces its stomach out of its mouth. Here, it uses enzyme-rich digestive fluids to liquefy its prey before drawing the food inside its body. A large part of a Forbes' sea star's diet is made up of mollusks. These mollusks only need to be partially opened for the sea star's stomach to enter the shell where it will digest the contents.

Arms

• Most Forbes's sea stars have 5 arms connected to the central part of their bodies. The majority of this animal's internal organs can be found within its arms. A single eye spot is located on the end of each arm. The sea star uses these eye spots to detect light levels. Sea stars are able to generate new arms if they lose any. This process can take up to 12 months and the sea star may grow more than one arm to replace the lost appendage.

Tube Feet

• The undersides of a Forbes sea star's arms are covered with tiny tube feet which serve a number of purposes. The Forbes' sea star grips onto surfaces and prey by building suction in its tube feet. To achieve this, the sea star draws water into a hole on top of its body called a madreporite. This creates pressure which leads to suction in the tubes. The sea star also uses this process to achieve movement, causing its tube feet to move through controlling water pressure levels in its body. By applying pressure, this sea star uses its tube feet to pry mollusk shells open.

Skeleton and Skin

• All sea stars are invertebrates, meaning that they do not have a backbone. However, these animals do not have an exoskeleton either. Like humans, sea stars have an endoskeleton but it is arranged very differently than the human skeleton. The Forbes' sea star has a skeleton that is made up of a number of small plates. These plates are connected by tissue which provides the sea star with flexibility. Sea stars are echinoderms.This means that they have a calcified layer of skin which protects the sea star's skeleton and protects the animal from predators. Bony spikes also protrude from the sea star's skin to defend it from attack. Although colors can vary from orange to purple, these sea stars are often brightly colored which also acts as a deterrent for predators.