WIKIMEDIA, P. LINDGRENA population of green turtles, whose sex is determined by in-nest temperatures, has become almost 99 percent female in recent decades, according to a report in Current Biology on Monday (January 8). Sea and air temperatures at the population’s nesting area have been steadily rising for the last 50 years, the report claims, leading the authors to conclude that climate change is responsible.
“The authors intriguingly report that the sex ratio of the northern Great Barrier Reef nesting population is substantially more female-biased in younger age classes,” Fredric Janzen, an ecologist and evolutionary biologist at Iowa State University who was not involved in the study, writes in an email to The Scientist. “Essentially, . . . this means the population [has been] producing excess numbers of female hatchlings in recent decades, consistent with the expected feminizing effects of climate warming.”
Like many reptilian species, sea turtles do not have specific sex chromosomes. “Eggs, when they are laid, can become either male or female,” explains biologist Jeanette Wyneken of Florida Atlantic University who also was not involved in the research. Their sex is instead determined by environmental factors—in the ...
