Head to head
Common Sea Urchin vs Purple Sea Urchin
Common Sea Urchin
VS Purple Sea Urchin
The common sea urchin of Europe and the purple sea urchin of the Pacific coast of North America are two kelp-grazing sea urchins that scrape rock with Aristotle's lantern.
| Common Sea Urchin | Purple Sea Urchin | |
|---|---|---|
| Scientific name | Echinus esculentus | Strongylocentrotus purpuratus |
| Look | A round, slightly flattened shell around 10 cm across, covered with short pinkish-red spines tipped with white | A rounded body covered in numerous movable spines, used for protection and slow movement across rock and reef |
| Diet | An omnivore eating kelp and other seaweeds, and encrusting animals such as sponges, barnacles, and sea mats | A herbivore feeding mainly on kelp and other algae scraped from rock |
| Feeding tool | Five hard teeth in Aristotle's lantern, which scrape algae from rock | Aristotle's lantern, made of several hard plates and teeth that scrape algae directly off rock |
| Habitat | Rocky seabeds and kelp, from the low shore to deep water in the northeast Atlantic | Rocky coastal and kelp forest habitat along the eastern Pacific coast of North America |
| Ecological role | A locally common grazer on rocky seabeds | Can explode in number and overgraze kelp forests down to bare rock when predators decline, while sea otters help keep it in check |
| Notable fact | The roe is eaten as a delicacy in parts of Europe, which has led to local harvesting | Can live for several decades, with some individuals documented living for fifty years or more |
| Conservation status | Not Evaluated globally, though locally common | Least Concern |
Common Sea Urchin vs Purple Sea Urchin: common questions
What is Aristotle's lantern?
A set of hard teeth and plates inside a sea urchin, arranged in a structure that scrapes algae from rock.
Which urchin can destroy kelp forests?
The purple sea urchin, whose numbers can explode and overgraze kelp down to bare rock when its predators decline.
Which one is eaten?
The common sea urchin, whose roe is eaten as a delicacy in parts of Europe.