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215. The Pincushion Urchin (Colobocentrotus atratus)


A small herd of Pincushion Urchins (Colobocentrotus atratus), also known as the Helmet Urchin or Shingle Urchin, is grazing on coralline algae in the Mauritian tidal zone.

These urchins are perfectly adapted for a life on the rough, with waves battered rocky intertidal zones of the Indian and Pacific Oceans. Unlike most of their cousins, the typical spines are absent and have, over the course of evolution, been transformed into little flat plates. The mosaic-like structure is the near-perfect surface to withstand the strong waves crashing on the shores where this urchin has made its home. Adding a great number of very strong tube feet on its underside to ensure a firm grip on slippery and wet rocks, these urchins are extremely resistant to life in a zone where most animals would be flushed away by the incoming waves, like the little Rockskipper (Alticus monochrus) in this short underwater videoclip who is grazing on the green algae.

The spinelessness also means that no spines can break off when strong and forceful waves hit these urchins, with the result that the animal does not have to spend any energy to heal and repair the physical damage. The deep joints in between and underneath the slightly rounded honeycomb-like structures of the flattened spines are also excellent at retaining water, a feature that might come in handy if the urchin is exposed to the tropical sun and heat at low tide.

These slow animals are active hunters of periwinkles and other urchin species, although the Pincushion Urchin is most likely to be encountered while feeding on coralline algae.

Most of these intertidal urchins prefer to graze around in small to medium-sized aggregations. A group or an aggregation of urchins is called a “herd”.

In the American island state of Hawaii this echinoderm is called “hâʻukeʻuke” and considered as a delicacy. Here these urchins are cracked open so that their eggs can be eaten, similar to the Japanese dish "uni sushi”.


Marine wildlife videography and documentary making encompasses more than just capturing scenes beneath the water's surface. In addition to underwater video footage, marine wildlife videography often includes the documentation of geographical features related to the sea, and animals and their behaviours in proximity to the ocean or even beyond its boundaries. Wel known examples are animals like marine mammals (seals, sea lions, etc….), different species of sea birds (from the classical gulls to the magnificent penguins that roam the ice shelves of the Antarctic) and crustaceans like fiddler crabs for example. Other examples that are often included in marine wildlife filmmaking are river mouths, small islands and exposed rocks, steep cliffs, beautiful beaches, majestic icebergs, huge ice shelves, intertidal zones, tidal pools, etc. … Most documentaries that feature marine wildlife go beyond the aquatic realm to showcase the diverse and fascinating behaviours exhibited by marine life in their natural habitats, whether it be on the shoreline, coastal areas, or other environments closely connected to the ocean. By exploring the interactions between different marine creatures and their surroundings, marine wildlife videography provide a comprehensive and captivating portrayal of the intricate web of life in, above and around the sea.

Filming location:

This short underwater videoclip has been filmed in Mauritius 🇲🇺

More about this subject:

To find out more about other urchin species that occurs in Mauritian waters please visit our vlog post 98 or click the following link https://www.beyondscuba.com/post/a-burrowing-heart-urchin

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