A team of researchers, led by a Delhi University assistant professor, has discovered a frog with full leucism—the first recorded case in any frog species in India. This rare condition was found in an Indian bullfrog (Hoplobatrachus tigerinus) along the banks of the Suheli river in Dudhwa Tiger Reserve, Uttar Pradesh. The findings have been published in the scientific journal “Herpetology Notes.”
The discovery was made by Robin Suyesh, an assistant professor at Sri Venkateswara College, Swastik P. Padhy from the University of Minnesota, and Harshit Chawla from the TERI School of Advanced Studies during a field survey on December 3, 2021. The individual frog was completely white except for its eyes.
“Here, we report on the first case of complete leucism in the Indian bullfrog, Hoplobatrachus tigerinus. The individual exhibited a nearly complete white body, except for the eyes which showed no signs of depigmentation (typical of albinism) and a few discontinuous pigmented bands on the body. Even the tympana were nearly completely without colour,” stated the research paper published on July 20.
Indian bullfrogs, which are widespread throughout the Indian subcontinent, are generally olive green or yellow. Males turn bright lemon yellow during the breeding season, with a light-yellow vertebral streak. The discovery of the leucistic frog is noteworthy as it deviates significantly from these typical colorations.
Robin Suyesh explained that this is a case of complete leucism, a rare occurrence not just in India but globally. Leucism results in a partial or complete loss of pigmentation, sparing the eyes, unlike albinism, which affects all pigmentation including the eyes. The causes of such abnormalities can be genetic or influenced by external factors like disease, environmental conditions, pollution, and food availability.
Vineeth Kumar, a zoologist with extensive experience studying frogs in India, highlighted the rarity and significance of this finding. He mentioned that pigmentation alterations like leucism, albinism, and melanism can result from various factors, including radiation, genetic mutations, and agrochemicals. Amphibians, with their permeable skin and dual life stages, are particularly susceptible to environmental disturbances, making such discoveries critical for ecological studies.
Ashish Thomas, an assistant professor at Sri Guru Nanak Dev Khalsa College, emphasized the rarity of such cases due to the physiological and ecological disadvantages associated with color loss. He stressed the importance of further research and surveys to understand the genetic and external factors contributing to these conditions, especially in protected areas where such individuals are found.
This discovery of a fully leucistic Indian bullfrog not only adds a significant observation to herpetology but also underscores the need for more research into the environmental and genetic factors influencing such rare occurrences.