A fun activity in the Sea of Cortes is going snorkeling; the diversity of creatures is amazing, from planctonic organisms to all kinds of marine invertebrates, like this Socorro crown of thorns (Acanthaster ellisii), a sea star that honors its name since it is all covered with thorns or spines for protection. Sea stars, brittle stars, sea biscuits, sea cucumbers, and sand dollars among others belong to the phylum (group) Echinoderms, an entirely marine group. The Socorro crown of thorns feeds on the polyps of hard coral, and since in the Gulf of California coral patches and coral reefs are found, we are lucky to see them.