These tadpoles have discovered a unique way of not contaminating their water supply: not pooping

by Matthew Coslett, Nagoya University
September 25, 2024

The Eiffinger’s tree frog (Kurixalus eiffingeri), found on Ishigaki and Iriomote islands in Japan, has a unique biological adaptation: its tadpoles do not defecate during their early developmental stages. This finding by researchers at Nagoya University in Japan contributes to our understanding of how these small frogs survive in the tiny bodies of water where they spawn. The findings were published in the journal Ecology.

Eiffinger’s tree frogs rear their young in small, isolated water bodies, such as tree hollows and bamboo stumps, which provide a safe environment with few predators.

However, in these limited water spaces, the tadpoles face the challenge of waste management. Unlike other species that excrete toxic ammonia in their feces into larger water bodies where it is diluted and rendered harmless, the confined water environments of Eiffinger’s tree frogs do not allow them this luxury. Excessive defecation causes ammonia to build up in the tiny water bodies, leading to toxicity and endangering their survival.

Bun Ito, a special research student, and Professor Yasukazu Okada at the Graduate School of Science, Nagoya University, focused on this peculiar aspect of the frog’s life cycle and discovered that the tadpoles exhibit a remarkable strategy to managing their waste: they go for months without pooping.

To keep the water bodies clean, Eiffinger’s tree frog tadpoles excrete significantly less ammonia than other frog species. Instead of releasing waste into their environment, the tadpoles store it in their intestines, accumulating high concentrations of ammonia within their bodies.

Keep reading: https://www.nagoya-u.ac.jp/researchinfo/result-en/2024/09/20240925-02.html

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.4428