A study on male Asian common toads (Duttaphrynus melanostictus), conducted in India by a researcher from Tiergarten Schönbrunn, has received the Best Paper Young Scholar in Herpetology 2025 award, recognising the best scientific publication by an early-career herpetologist.
A colour change that lasts only a few days
A toad that suddenly changes colour, turning from brown to bright yellow during the breeding season, may have evolved this strategy to avoid mistaken mating attempts amid the chaos of explosive breeding events. This is the conclusion of a study led by Susanne Stückler, a researcher at Vienna’s Tiergarten Schönbrunn, which was recently honoured at the Joint Meeting of Ichthyologists and Herpetologists in New Orleans with the “Best Paper Young Scholar in Herpetology 2025” award.
The research focused on the breeding behaviour of the Asian common toad (Duttaphrynus melanostictus), a species found in India that undergoes a spectacular colour change during its extremely short breeding season, which lasts only one or two days each year.
Males, normally brown in colour, suddenly turn bright yellow precisely during the breeding period.
According to the study, this transformation serves a very specific purpose: reducing mistaken mating attempts during so-called explosive breeding events, when hundreds of individuals reproduce simultaneously in the same bodies of water.
3D-printed toads
To test this hypothesis, the research team used an unusual method: three-dimensional toad models, produced in both brown and yellow versions and placed directly in the breeding sites.
«We reached this conclusion by using brown and yellow 3D toad models placed in the water during the frantic breeding events involving hundreds of individuals. We observed that males clasped the brown models far more frequently than the yellow ones,» explains Susanne Stückler.
The findings therefore suggest that the yellow colour signals to other males not to attempt mating, reducing interference during reproduction.
Zoo-based research supporting conservation
For Tiergarten Schönbrunn, research is one of the zoo’s core missions alongside conservation and education.
«Research conducted in and with zoos often provides the foundation for successful species conservation initiatives and also helps us continuously improve animal care and management,» says Zoo Director Stephan Hering-Hagenbeck.
In 2025 alone, Tiergarten Schönbrunn collaborated with 46 universities, research institutions, zoos and aquariums around the world.
The award-winning study was carried out in collaboration with the University of Vienna, Brown University (USA), Indian naturalist Gopalkrishna Hedge, and herpetologist KV Gururaja.
The research continues
The investigation into the Asian common toad does not end with this award.
«We continue to study this amphibian species both in its natural habitat and at the zoo. We are conducting behavioural studies and investigating the hormonal mechanisms behind this fascinating colour change. There is still much to discover,» concludes Doris Preininger, researcher at Tiergarten Schönbrunn and supervisor of the study.
The international award recognises not only the originality of the research, but also the important contribution that zoo-based scientific studies can make to understanding animal behaviour and conserving biodiversity.
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