Sea urchins may not be as famous as sharks or sea turtles, but these fascinating, spiny creatures play a vital role in ocean ecosystems. Found in oceans around the world, sea urchins help keep marine habitats healthy by grazing on algae that can otherwise overgrow reefs and seagrass beds. Their unique appearance and important ecological role make them one of the most interesting animals to discover while exploring coastal waters.

 

 

 

 

 

 

 

 

 

What Are Sea Urchins?

Sea urchins are marine invertebrates called echinoderms, related to other slow moving creatures like sea stars and sand dollars. Their bodies are covered in movable spines that help protect them from predators and assist with movement across the seafloor. Beneath those spines is a surprisingly complex animal equipped with hundreds of tiny tube feet that help it grip rocks and navigate underwater environments. Sea urchins primarily feed on algae, making them important caretakers of reef ecosystems.

 

 

 

 

 

 

 

 

 

 

Sea Urchins Hidden in Florida’s Seagrass Meadows

Not all sea urchins live on coral reefs. Several species can be found among Florida’s extensive seagrass beds, where they blend surprisingly well into their surroundings. Collector urchins, for example, are known for covering themselves with shells, seagrass blades, and other debris as camouflage. These underwater meadows provide both food and protection, making them an ideal habitat for young urchins and countless other marine animals. Snorkelers often swim right over them without realizing they're there.