Information

The sea urchin - Wanted poster


Characteristics

Surname: Sea urchin
Latin name: Echinoidea
class: Sea urchin
size: 5 - 30cm
mass: 50 - 200g
Older: 10 - 200 years
Appearance: different colors possible
food: Algae, sea cucumbers, sponges
distribution: worldwide
habitat: Oceans
natural enemies: Fish, sea otters, wolfaal
sexual maturity: unknown
mating season: all year round
oviposition: up to 2,000,000 eggs
social behavior: ?
Threatened with extinction: No
Further profiles of animals can be found in the Encyclopaedia.

Interesting about the sea urchin

  • The first sea urchins appeared in the Ordovician (480 million years ago).
  • The sea urchin is not related to the hedgehog despite its name. The sea urchin owes its name to the hedgehog-like spines that protect it from predators (defensive function). In addition, the spines also facilitate locomotion over the seabed.
  • The skeleton of sea urchins consists mostly of calcium carbonate (lime).
  • Sea urchins do not have a real brain, but a thickened ring of nerve cells.
  • During reproduction, male and female sea urchins simultaneously release their egg and sperm cells into the water. To increase the probability of fertilization, this sometimes happens even in larger sea urchin groups.
  • Most sea urchins filter algae out of the water. Some sea urchins also eat sea cucumbers, sponges, clams and even young fish.
  • Sea urchins have two body orifices: a mouthpiece for food intake and an intestinal outlet. The mouthpiece is also called "lantern of Aristotle", after the first observer and Greek philosopher Aristotle.
  • Certain sea urchins (for example red tiara urchins) can inject poison through their spines when in contact. In the case of involuntary contact, one should therefore be immediately out of the water, as paralysis phenomena occur, and in the worst case, may lead to death.
  • In Japan sea urchin eggs and gonads (gonads) are considered an expensive delicacy.