Everyone loves dressing up for Halloween, even the urchins! At Contact Cove, the variegated urchins get little plastic cowboy hats and huge goofy eyeballs to wear. It is hilarious and adorable, but it also encompasses an important behavior trait of these urchins. They like to cover themselves in debris they find in their habitat.
The variegated urchin (Lytechinus variegatus) is typically found in the Western Atlantic, ranging from North Carolina to Brazil, including the Caribbean and the Gulf of Mexico. Variegated urchins live in shallow waters (up to 50 meters) such as seagrass beds, sandy bottoms, and coral reefs. They have a spherical body covered in short protective spines that vary in color from green to purple, often with a mottled or variegated pattern.
As you can see in the pictures, variegated urchins will cover themselves with debris such as shells, algae, and small rocks. This covering behavior serves several purposes, including camouflage, UV light protection and cleanliness. They use their tube feet to pick up these objects and hold them in place.
The camouflage factor is fairly obvious – predators are more likely to overlook an urchin that looks like pile of rubble when swimming above. The debris also helps shield the urchin from harmful UV radiation, especially in the clear, shallow waters where they are often found. Finally, if you look at the algae and crud that has settled on some of the hats, you will get an idea of how this promotes cleanliness for the urchins as well.
Sources:
- Sigg JE, Lloyd-Knight KM, Boal JG. UV radiation influences covering behaviour in the urchin Lytechinus variegatus. Journal of the Marine Biological Association of the United Kingdom. 2007;87(5):1257-1261. doi:10.1017/S0025315407055865
- Lytechinus variegatus. Wikipedia. https://en.wikipedia.org/wiki/Lytechinus_variegatus
Erica Lauer Vose 