Is it a boy or girl baby sea turtle ? FAU researchers find new way to tell
Is it a boy or is it a girl? For baby sea turtles it’s not that cut and dried.
Believe it or not, baby sea turtles don’t have an X or Y chromosome. Instead, the warmer the sand is in their nests, the more likely it is the turtles will develop as females. Cooler sand temperatures produce more males.
“My students will describe it as hot chicks, cool dudes,’” Boca Raton-based Florida Atlantic University biological sciences professor Jeanette Wyneken said Thursday.
Surveys of loggerhead turtles for more than 10 years in Palm Beach County have shown there are more females. In addition, in some nests, more males occur than would be predicted by nest temperature alone.
To make things even more complicated, in some species of sea turtles, their sexual anatomy is not apparent until about a decade or so when they approach sexual maturity. Examining the turtles with instruments in a brief surgical procedure has been the traditional way to determine their sex.
Now Wyneken and two other FAU scientists have developed and tested a new way to identify the sex in hatchling loggerhead and leatherback turtles. The results are published in the journal The Anatomical Record.
The research will help scientists find out if there’s a viable population of sea turtle hatchlings because the population has been trending heavily female in the last few years, increasing the turtles’ chances of extinction. Without enough males, the population could decline further.
The new method is especially crucial for endangered leatherback turtles, said Wyneken, Ph.D., who collaborated on the study with Boris M. Tezak, first author and an FAU graduate student, and Kathleen Guthrie, Ph.D., associate professor of biomedical science in FAU’s Charles E. Schmidt College of Medicine.
The researchers used dyes to stain protein cells of turtles who had died of natural causes in their nests. They found that the females’ proteins turned purple, but the males’ showed no change.
Now researchers can also find out if the same issue of too many female turtles and too few males is occurring with leatherbacks, a species whose sexual identity is even more difficult to determine.
If the turtles’ sex can be determined early, then researchers can figure out what steps might be needed to balance the population.
“If there’s a problem, we need to know now, not 25 years from now,” Wyneken said. “We’re seeing big changes in the number of summers in which we get 100 percent females. Last year we had 100 percent females, and the year before.”
The new research tool can be used to establish baseline hatchling sex ratios and to assess climate change effects on turtle hatchlings and sea turtle demographics.
The Sea Turtle Conservancy, states that the leatherback sea turtle is listed as endangered (in danger of extinction within the foreseeable future) under the U.S. Federal Endangered Species Act and worldwide it is listed as vulnerable in 2013 (facing a high risk of extinction in the wild in the immediate future) by the International Union for Conservation of Nature and Natural Resources.
The loggerhead sea turtle is listed as threatened (likely to become endangered, in danger of extinction, within the foreseeable future) under the U.S. Federal Endangered Species Act and internationally it is listed as endangered by the International Union for Conservation of Nature and Natural Resources.
This research is supported by the Gumbo Limbo Gordon J. Gilbert Graduate Scholarships, the National Save the Sea Turtle Foundation and the FAU Foundation’s Nelligan Sea Turtle Research Support Fund.