# Sea Urchin (*Breynia sp. (in: sea urchins)*) Sea urchins are spiky creatures that live in the ocean. They come in different colors like purple, red, and green. Sea urchins move very slowly and use their spines for protection. - **Category:** [Invertebrate](https://www.snappit.app/explore/categories/invertebrate) - **Rarity:** Common - **Danger:** 3/5 · Moderate - **Habitat:** Marine - **Also known as:** Echinoid, Sea Hedgehog ![Sea Urchin](https://res.cloudinary.com/drieglelr/image/upload/v1771426621/objects/6400.jpg) ## Appearance The Sea Urchin has a round or flattened body covered in long, sharp spines that can be black, brown, green, or purple. It looks like a spiky, living pincushion, distinct from soft-bodied sea anemones. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Echinodermata - **Class:** Echinoidea - **Order:** Spatangoida - **Family:** Loveniidae - **Genus:** Breynia ## Interesting facts - If a spine breaks off, a sea urchin can grow a brand new one! - Sea urchins can wear hats of shells or pebbles for camouflage and sun protection! - Some sea urchins live over 200 years, making them ancient ocean dwellers! - They chew food using five hard teeth, called Aristotle's lantern! ## Special abilities - **Spine Shield:** Sea Urchin has many sharp spines that helps them poke away predators, like a living shield. - **Suction Cup Feet:** Sea Urchin can move slowly and stick to rocks, even upside down, because of hundreds of tiny tube feet. - **Algae Chomper:** Sea Urchin can chew tough algae and other food because of their five-toothed 'Aristotle's Lantern' mouth. ## Measurements & details - **Size:** 10 cm - **Lifespan:** 200 years - **Approx Species Count:** 950 ## Diet & Feeding Sea urchins mostly munch on algae but will also eat tiny critters and decaying plants. - **Primary Foods:** algae, kelp, detritus, small invertebrates - **Foraging Method:** Grazing ## Ecological connections - **Eats:** [sea otter](https://www.snappit.app/explore/sea-otter) (*Enhydra lutris*) — Sea otters are a major predator of sea urchins. - **Eaten by:** giant kelp (*Macrocystis pyrifera*) — Sea urchins graze on kelp, sometimes forming 'urchin barrens'. - **Eats:** [sunflower sea star](https://www.snappit.app/explore/sunflower-sea-star) (*Pycnopodia helianthoides*) — This large sea star preys on sea urchins. - **Eats:** California sheephead (*Semicossyphus pulcher*) — This fish crushes and eats sea urchins with its strong teeth. ## Traits - [Wildlife](https://www.snappit.app/explore/traits/wildlife): Wildlife encompasses all undomesticated animal and plant life existing in their natural habitats. - [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care. - [Filter Feeder](https://www.snappit.app/explore/traits/filter-feeder): Filter feeders obtain nutrients by straining suspended food particles and small organisms from water. - [Herbivorous](https://www.snappit.app/explore/traits/herbivorous): This trait characterizes organisms whose diet consists entirely or primarily of plant material. - [Spiky/Thorny](https://www.snappit.app/explore/traits/spiky-thorny): Possessing sharp, pointed projections or spines on the body or surface. - [Keystone Species](https://www.snappit.app/explore/traits/keystone-species): Describes a species whose presence and role have a disproportionately large effect on its environment. - [Marine](https://www.snappit.app/explore/traits/marine): Marine habitats encompass all saltwater environments of the Earth's oceans, supporting an immense diversity of aquatic life. ## Collections - [Invertebrates](https://www.snappit.app/explore/collections/invertebrates) ## Safety **Danger:** 3/5 · Moderate Avoid touching sea urchins in the wild as their spines can hurt you. ## Frequently Asked Questions ### How to identify Sea Urchin? Look for fins, arms, tentacles, shells and body symmetry. Underwater light shifts colors, so structure and markings usually matter more than shade. Sea Creature Identifier: upload a photo and compare the visible details. ### How big is Sea Urchin? 10 cm ### How long does Sea Urchin live? 200 years ### What does Sea Urchin eat? Sea urchins mostly munch on algae but will also eat tiny critters and decaying plants. ### Where is Sea Urchin usually found? Marine ### How does Sea Urchin hunt? Grazing ### How many species does Sea Urchin include? 950 ## Where to spot - [Heal the Bay Aquarium](https://www.snappit.app/guides/places/heal-the-bay-aquarium) — California, US · Zoo ## More Invertebrate - [Coral](https://www.snappit.app/explore/coral) - [Crab Spider](https://www.snappit.app/explore/crab-spider) (*Mecaphesa asperata*) - [Garden Spider](https://www.snappit.app/explore/garden-spider) (*Araneus diadematus*) - [Brown Recluse Spider](https://www.snappit.app/explore/brown-recluse-spider) (*Loxosceles reclusa*) --- Source: [Sea Urchin: Characteristics, Facts & Places to See — Snappit](https://www.snappit.app/explore/sea-urchin)