Indian Toads Turn Bright Yellow In Stunning Breeding Season Transformation

A research project from Schönbrunn Zoo has received international recognition after scientist Susanne Stückler, PhD, was awarded for her study on black-spotted toads in India.

The study focused on a rare natural event during the one- to two-day breeding period, when male black-spotted toads change from an ordinary brown color to bright yellow.

Researchers found that the striking color change may help prevent mistaken pairings during the intense mating activity.

Stückler explained that the discovery came through experiments using brown and yellow 3D toad models placed among hundreds of animals during the breeding period. The results showed that males embraced the brown models significantly more often than the yellow ones.

The award-winning research was recognized as the “Best Paper Young Scholar in Herpetology for 2025” at the Joint Meeting of Ichthyologists and Herpetologists, an international conference for fish, amphibian, and reptile research.

The study involved the University of Vienna, Brown University in the United States, local farmer Gopalkrishna Hedge, and herpetologist KV Gururaja, PhD.

Researchers continue studying the amphibians in their natural habitat and at Schönbrunn Zoo, including behavior studies and the hormonal mechanisms behind the unusual color change.