Don’t Like the Heat? Neither Do Boy Turtles.

The gender ratio of humans is nearly equal—100 women to 97 men. In nature, things can get a lot more skewed. There are generally more male birds than females (around a 60/40 ratio) and sex of the offspring is affected by time of year, environment, and the female’s body condition. In sea turtles, the sex ratio has gotten terribly off. In 2022. scientists studying turtles in Florida found that 99% of sea turtle babies were female. With such a ratio, successful breeding to maintain the species’ population is all but impossible.

When a female turtle digs a nest on a beach, the temperature of the sand and developing eggs determines the sex of the hatchlings. If a turtle’s eggs incubate below 82°, the turtle hatchlings will be male. If they incubate above 89°, they will be female. The last four summers in Florida have been the hottest on record, resulting in almost no boy turtles.

Why care about sea turtles? They play a vital role in marine ecosystems and have helped maintain ocean health for over 100 million years. They graze on seagrass beds, pruning them to keep them healthy. Seagrass provides critical habitat for many species of fish and shellfish. Turtles help ecosystems on land as well. Eggs laid on beaches increase nutrients in the sand, promoting vegetation growth that stabilizes sand dunes and barrier islands. The dunes/islands in turn protect inland areas from severe storms and erosion, also supporting additional wildlife.

The more research scientists do, the more they realize the interdependence of all living things. Humans need the services provided by many organisms for life’s essentials—oxygen, food, shelter, medicines and livelihoods. Hopefully we can pay better attention to their needs, slow the rate of ecosystem change and give them time to adapt.