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Marine Animal Encyclopedia

Long-spined Sea Urchin Diadema savignyi

Many divers on coral reefs have learned to avoid these sea urchins. They bristle with long, sharp spines that can easily wound, even through a wetsuit. The spines are mildly venomous and so brittle that they may break off in the wound. If a diver or predator comes near it, this sea urchin waves its spines vigorously. Only a few tough fish, such as the titan triggerfish, can successfully attack and eat such prickly prey. This species often has striped spines, while the other common Indo-Pacific long-spined species, Diadema setosum, has black spines.

Long-spined Sea Urchinzoom image
  • Class Echinoidea
  • Diameter Up to 9 in (23 cm)
  • Depth 0–230 ft (0–70 m)
  • Habitat Coral and rocky reefs
  • Distribution Tropical waters of Indian and western Pacific oceans
Long-spined Sea Urchin habitat mapzoom image