Johana Goyes Vallejos is an evolutionary behavioral ecologist interested in sexual selection and the evolution of mating systems. She researches mate choice, parental care, natural history and communication in animals, including frogs.

When Johana Goyes Vallejos travelled to Borneo , she discovered that instead of boy frogs making all the noise—which is how things typically go in frog world—it was female voices piercing the night air. Loud and proud, female guardian frogs searched for and pursued males instead of the other way around.

Johana also discovered that after the females laid eggs, their male mates stuck around and watched to make sure the eggs were safe. Then, once the tadpoles hatched, the dads did something extraordinarily sweet. The tiny tadpoles climbed onto their backs, and with offspring hanging on piggyback, the dads would take off. They hopped around the general vicinity until they located water bodies where the tadpoles could grow, and then they deposited the tadpoles in the water.

Biologists call this sex role reversal, and while it’s not common, sex role reversal is fascinating. Studying its occurrences adds to a more complete picture of sex roles in animals.

Johana is a postdoctoral research associate at the ​Biodiversity Institute at the University of Kansas and here is her website. The New York Times wrote an article about Johana’s discovery, and here’s a video where Johana speaks about this part of her research. National Geographic has an article in Spanish about the findings.

Watch this video to the end—it’s worth it! You’ll see the male guardian frog watching eggs, and later the tadpoles climb aboard for their ride.

This male smooth guardian frog, Limnonectes palavanensis, is carrying tadpoles on his back. The males are the ones who provide parental care in this particular species. Johana discovered this at a biological field station in Brunei, a small country on the island of Borneo in the South Pacific.