Males or Females, That's the Question

Did you know, the sex of a sea turtle is primarily determined by the sand temperature during incubation?

For loggerhead sea turtles, the warmer eggs toward the top of the nest, closest to the sunlight, generally hatch as females while the ones in the cooler sand at the bottom of the nest generally hatch as males.

Data collected in 2002 and 2003 on Sanibel showed 20-60% of hatchlings from the monitored nests were male, higher than all other Florida beaches except for Miami Beach.

Another year of data collection is needed to statistically show Sanibel's tendency to produce males.

A total of 10 nests are being selected during the 2009 nesting season to have a temperature sensor buried in the egg chamber. The sensor records the temperature in the nest for the duration of the incubation period. Near the estimated hatch date of a nest, a cage will be placed over the egg chamber to catch the hatchlings. Ten of the strongest hatchlings will be taken for a study that is being done as part of the Sea Turtle Research, Monitoring and Protection Program at the Florida Atlantic University and the University of Alabama. Those 10 turtles will be raised in their lab until they are old enough to be sexed. The rest of the hatchlings will be released.

Hopefully those studies will help answer the question, why Sanibel produces more male Loggerhead sea turtles.