( Related: 99 percent of these sea turtles are turning female-here’s why.) might be turning larval male amphibians into females. In 2014, a paper in the Proceedings of the National Academy of Sciences found that pollution-laden runoff into suburban ponds in the U.S. Research has also begun to suggest this happens in the wild. In the laboratory, certain pollutants like synthetic estrogens and herbicides have been shown to induce genetically male frogs to develop outwardly as females. They’re mainly influenced by genetics, but the environment also plays a role.
Mammals, however, are much more bound to genetics: If you’re genotypically male in the womb, you’re likely to develop outwardly as such.Īmphibians such as frogs lay somewhere in the middle. Sea turtles that grow up in warmer sand are more likely to become female, for example. What determines whether an animal becomes male or female? For frogs, sex is much more complicated than we thought.įor some creatures, like reptiles and fish, sex can be heavily influenced by the environment.
