# Strongylocentrotus purpuratus The purple sea urchin is a spiky little creature that lives in the ocean. It has a hard shell covered in sharp spines, which helps protect it from hungry animals. - **Category:** [Invertebrate](https://www.snappit.app/explore/categories/invertebrate) - **Rarity:** Common - **Danger:** 3/5 · Moderate - **Snaps:** 2 - **Habitat:** Coastal areas - **Also known as:** Purple Sea Urchin ![Strongylocentrotus purpuratus](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Strongylocentrotus_purpuratus_1.jpg&width=800) Photo: Taollan82, CC BY 3.0 · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Strongylocentrotus_purpuratus_1.jpg) ## Appearance The Strongylocentrotus purpuratus is a spherical echinoderm covered in sharp, movable spines that range from deep purple to reddish-brown. It has a hard, spiny shell called a test, making it look like a prickly underwater ball. Its spines are relatively short and uniform, unlike some long-spined urchin species. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Echinodermata - **Class:** Echinoidea - **Order:** Camarodonta - **Family:** Strongylocentrotidae - **Genus:** Strongylocentrotus ## Interesting facts - Each urchin has five-fold symmetry, meaning it's almost perfectly star-shaped inside! - Purple sea urchins can survive for hours out of water if kept moist. - Their spines are not poisonous but can give a painful poke if stepped on. - They use tiny tube feet with suction cups to slowly crawl across the seafloor. ## Special abilities - **Spine Re-Grower:** Strongylocentrotus purpuratus can regrow lost spines and even damaged body parts because it has remarkable regenerative capabilities that help it recover from injuries. - **Super Sticky Feet:** Strongylocentrotus purpuratus has hundreds of tiny tube feet that help them cling tightly to rocks and surfaces, even in strong currents, preventing them from being washed away. - **Rock Scraper:** Strongylocentrotus purpuratus has a unique mouth called 'Aristotle's lantern' equipped with five hard teeth that help them scrape algae off rocks for food. - **Scent Talker:** Strongylocentrotus purpuratus can detect chemical cues in the water, which helps them find food, avoid predators, and even locate mates. ## Measurements & details - **Length:** 4-10 cm - **Weight:** 0.05-0.2 kg - **Lifespan:** 30-70 years - **Speed:** 0.006 km/h ## Diet & Feeding These spiky creatures love to munch on algae and kelp, keeping ocean habitats clean. - **Primary Foods:** kelp, algae, seaweed, detritus - **Foraging Method:** Grazing ## Ecological connections - **Eaten by:** [Sea Otter](https://www.snappit.app/explore/sea-otter) (*Enhydra lutris*) — Sea otters are a major predator that crush urchins with their strong jaws. - **Eaten by:** [Sunflower Sea Star](https://www.snappit.app/explore/sunflower-sea-star) (*Pycnopodia helianthoides*) — Sunflower sea stars can engulf and digest sea urchins with their many arms. - **Eats:** Giant Kelp (*Macrocystis pyrifera*) — Urchins graze on giant kelp, sometimes leading to 'urchin barrens' when populations boom. - **Eaten by:** California Sheephead (*Semicossyphus pulcher*) — California sheephead fish use their powerful jaws to crush sea urchins for food. ## Traits - [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. - [Colorful](https://www.snappit.app/explore/traits/colorful): Colorful describes organisms or objects displaying a wide range of bright and distinct colors. - [Herbivorous](https://www.snappit.app/explore/traits/herbivorous): This trait characterizes organisms whose diet consists entirely or primarily of plant material. - [Longevous](https://www.snappit.app/explore/traits/longevous): This trait characterizes organisms with an exceptionally long lifespan compared to others of their kind. - [Spiky/Thorny](https://www.snappit.app/explore/traits/spiky-thorny): Possessing sharp, pointed projections or spines on the body or surface. - [Coastal](https://www.snappit.app/explore/traits/coastal): Coastal habitats are dynamic environments located along the interface between land and sea, influenced by tides, waves, and saltwater. - [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. - [Endangered](https://www.snappit.app/explore/traits/endangered): Endangered status indicates a species is at a very high risk of extinction in the wild in the near future. ## Collections - [Fish](https://www.snappit.app/explore/collections/fish) - [Marine Life](https://www.snappit.app/explore/collections/marine-life) ## Safety **Danger:** 3/5 · Moderate Be careful around sea urchins, as their spines can be sharp and hurt if touched. ## Frequently Asked Questions ### How to identify Strongylocentrotus purpuratus? 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 long is Strongylocentrotus purpuratus? 4-10 cm ### How much does Strongylocentrotus purpuratus weigh? 0.05-0.2 kg ### How long does Strongylocentrotus purpuratus live? 30-70 years ### How fast can Strongylocentrotus purpuratus move? 0.006 km/h ### What does Strongylocentrotus purpuratus eat? These spiky creatures love to munch on algae and kelp, keeping ocean habitats clean. ### Where is Strongylocentrotus purpuratus usually found? Coastal areas ### How does Strongylocentrotus purpuratus hunt? Grazing ## Where to spot - [Crystal Cove Historic District](https://www.snappit.app/guides/places/crystal-cove-historic-district) — California, US · Historic District - [Arena Cove Historic District](https://www.snappit.app/guides/places/arena-cove-historic-district) — California, US · Historic District - [Audubon Canyon](https://www.snappit.app/guides/places/audubon-canyon) — California, US · Nature Reserve - [Fort MacArthur](https://www.snappit.app/guides/places/fort-macarthur) — California, US · Historic Site - [King Range](https://www.snappit.app/guides/places/king-range) — California, US · Nature Reserve - [Coast Dairies State Park](https://www.snappit.app/guides/places/coast-dairies-state-park) — California, US · State Park [View all places to see Strongylocentrotus purpuratus](https://www.snappit.app/guides/where-to-see/strongylocentrotus-purpuratus) ## 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: [Strongylocentrotus purpuratus Facts — Snappit](https://www.snappit.app/explore/strongylocentrotus-purpuratus)