Sea Urchin (specifically the test or shell of a sea urchin)
Scientific Name: Echinoidea (This is the class name, as the specific species cannot be identified from the test alone)
Order & Family: Class: Echinoidea (This is a class, not an order/family, as the specific species and thus order/family cannot be determined from the test alone). Common orders include Cidaroida and Echinoida.
Size: The size of the test varies greatly depending on the species, typically ranging from 3 cm (1.2 inches) to 10 cm (4 inches) in diameter, but some can be larger.
Natural Habitat
Sea urchins are marine invertebrates found in a wide range of ocean environments, from shallow intertidal zones to deep ocean floors. They prefer rocky substrates, coral reefs, and kelp forests where they can find food and shelter.
Diet & Feeding
Sea urchins are primarily herbivores, grazing on algae, especially kelp. Some species are omnivores and may consume small invertebrates, detritus, and carrion.
Behavior Patterns
Sea urchins move slowly using their tube feet and sometimes their spines. They are primarily nocturnal grazers. The shell (test) is what remains after the animal dies and the spines fall off. The radial symmetry is evident in the pattern on the test.
Risks & Benefits
Live sea urchins can pose a risk to humans due to their sharp spines, which can cause painful punctures and introduce toxins or infections. Ecologically, they are crucial grazers that help maintain the balance of kelp forests and coral reefs. Their tests (shells) are often collected as decorative items.
Identified on: 7/3/2025