Why do sea turtles scratch their shell?

Sea turtles scratch their shells to clean them. This self-grooming behaviour helps them remove epibionts such as barnacles or algae. Excessive epibiont growth would otherwise impair the turtle’s movement and swimming ability.

Green turtle with excessive barnacles, Oman
Green turtle with barnacles, Oman ©Zoe Cox


  • Frick MG and McFall G 2007. Self-Grooming by Loggerhead Turtles in Georgia, USA. Marine Turtle Newsletter 118: 15.
  • Schofield G, Katselidis KA, Dimopolous P, Pantis J and Hayes GC 2006. Behaviour analysis of the loggerhead turtles Caretta caretta from direct in-water observations. Endangered Species Research 2: 71-79.