Repetitive Nesting Behaviors in Sea Turtles

Blog Post By: Aidan, Sea Turtle Intern

        Recently, we have been having a nesting loggerhead nicknamed “crazy turtle”. This turtle has been repetitively coming ashore and leaving behind numerous body pits. The mystery of this turtle was solved when our night walk saw that this turtle was incapable of properly digging an egg chamber. This led me to think about what causes these sorts of strange nesting behaviors in sea turtles.
          Oftentimes, nesting turtles tend to follow similar nesting behaviors when they come ashore to nest over the years. Some turtles show preferences for nesting higher up the beach in the dunes while others nest lower below the high tide line. Some individuals might be more selective as to where they nest and might false crawl more than other turtles. Last summer while interning in Costa Rica, I observed a green sea turtle intent on moving several hundred feet into the rainforest next to the beach. It would remain ashore for hours every night sometimes trying to body pit and dig egg chambers on the roots of trees. I also witnessed a feisty green sea turtle that would snap its jaws and throw its flippers at us when attempting to read tags. It abandoned the nest covering and disguising process at the slightest disturbance.
            Sea turtles have a small peanut-sized brain that is minuscule compared to the size of the mammalian brain. They lack the part of their brain that allows them to establish thought processes as we do. Due to this, sea turtles rely entirely on instinct as opposed to thinking and emotion. This explains why such behaviors are repetitive and do not normally improve over time.  The behavior observed in our “crazy turtle” is likely caused by neurological conditions that affect how the turtle interprets its instincts. Behaviors in other turtles might be caused by genetics or physical injuries that affect the nesting process.
           These peculiar turtles are simply following what they think will lead to a successful nest. However, their instincts are not as they are meant to be, and these nesters will struggle to produce a viable clutch. While instinct is beneficial for turtles allowing them to survive and nest without any parental care, it does have its negatives. It will be interesting to see if our strange nesting loggerhead returns to our beach again in two to three years time.