Why frogs turn yellow during group sex

Frog sex can get weird: It often occurs in big heaving groups with multiple members of each sex piled on top of one another. In most species, females release eggs into the environment and then males immediately release sperm to fertilize them. Interestingly, male frogs in species that tend to mate en masse often take on a bright yellow hue during mating season. Now, a new study in the Journal of Evolutionary Biology suggests that the color change may serve as a visual aid to other males to stay away. The hypothesis comes from a review of existing literature that found 95 species exhibit the trait, Popular Science reports. The researchers are planning to follow up with experiments to find out how and whether the frogs perceive the yellow pigments.