What’s Going On?

Like alligators and most other turtles, sea turtles lack sex chromosomes. Instead of being genetically predetermined to be a male or female, their sex entirely depends upon the surrounding temperature of the sand, where the eggs are incubated.   

This means that, on average, eggs that incubate below 81.86 degrees Fahrenheit (27.7 degrees Celsius) will be male, and eggs that incubate above 88.8 degrees Fahrenheit (31 degrees Celsius) will be female.

A clutch, or grouping of turtle eggs, that incubates between these thresholds will have a mix of male and female hatchlings.  

You can remember how temperature affects sea turtle sex by remembering the phrase
“Hot Gals, Cool Dudes!” 

The “pivotal temperature” is defined as the temperature at which 50% of the eggs will produce female offspring. This temperature varies across sea turtle species, and also across different nesting grounds.  

Why it Matters

A slightly female-biased sex ratio may actually be preferred since one male can mate with many females, and females only reproduce every three years.  

However, with global temperatures on the rise, that ratio may be getting too skewed.  

One study on the north of Australia’s Great Barrier Reef found that 99% of immature green sea turtles were born female, while 87% of adult turtles in the same area were female. This indicated that the proportion of female hatchlings has increased in recent years. 

This trend has been seen across Florida as well, where five out of the world’s seven sea turtle species come to feed and lay their eggs every year.  

If sea turtles continue to hatch consistently and overwhelmingly as females, there may not be enough males to fertilize the overabundance of females. This could lead to a decline in genetic diversity within the population.

They come to sexual maturity over the course of 25-40 years, so the effects on hatchlings today may not be seen for decades to come. 

Sea turtles are also battling other dangers caused by humans and climate change, including rising sea levels. As a result, these already endangered animals could face extinction in the future.

Sea turtles are a keystone species and are vital to maintaining the health of marine and coastal ecosystems in Florida and beyond. This makes climate change mitigation all the more important so we can preserve sea turtle populations for future generations!

What You Can Do!

There are many levels of action that can be taken to reduce the effects of climate change, stabilize sea turtle sex ratios, and protect sea turtles from other anthropogenic harms.  

Reducing the Effects of Climate Change 

  • Support lawmakers, nonprofit organizations, and legislation striving to make fundamental changes to reduce global warming and greenhouse gas emissions.  
  • Make small changes to your everyday routine to reduce your individual environmental footprint. 
    •  Walk, bike, and use public transportation whenever possible.  
    • Turn off lights when they are not in use.
    • Eat more vegetables and foods with a smaller carbon impact.
    • Consider switching to renewable forms of energy.  

Get Involved 

  • Join a volunteer sea turtle task force in your area, to help identify and mark off sea turtle nesting sites.  
  • Respect coastal dunes and vegetation by walking on designated pathways. Dunes and vegetation not only help hatchlings orient themselves toward the water when they emerge, but they provide shade that can cool down nests and prevent sex ratio skewing. ‘ 
  • Visit the following link for more steps on how to protect sea turtles!
  • Want to learn more about sea turtle research in Florida?

 

Information from NOAA, National Geographic, and the New York Times.