Frequently observed by snorkelers and divers, sea urchins are abundant in the Hawaiian Islands. These echinoderms are closely related to sea stars and sea cucumbers and use tube feet that extend through their pores to help cling and move along surfaces. They are characterized by a globular or flattened skeleton, called a test, and have hundreds of moveable spines, tube feet, and tiny pincer-like organs called pedicellariae.

Spines on sea urchins vary between species and serve as a form of protection from various predators. Some have long, sharp spines, others have massive blunt spines, and some species even have venomous spines. The long-spined urchin, or wana in Hawaiian, is one of the venomous species and can inject a painful sting. The pain usually settles within a few hours, but the spines will remain inside for extended periods, with your body eventually absorbing them with no potential danger.

Sea urchin reproduction happens through spawning, where male and female urchins will simultaneously release eggs and sperm into the water. Fertilized eggs then hatch into larvae that drift in the planktonic stage and later settle as bottom dwellers. Sea urchins generally graze on algae, and their mouths are located on the underside of the animal.

*Due to the constant rotation of animals back to the ocean, we cannot guarantee the presence of any specific animal.