2012 Brahminy river turtle

Photo: Tomáš Adamec, Prague Zoo

First time ever bred

The first brahminy river turtle to be bred in captivity was not only a breakthrough in breeding, but also a scientific one. After four years of study, it was possible to reveal the unique way this endangered freshwater species from India breeds. When reptile curator Petr Velenský noticed that one of the turtles released its eggs directly into the water, he concluded it was not a mistake and approached Indian herpetologist Dhruvajyoti Basu, who confirmed that local fishermen said something similar. He also shared insights from the reproductive cycle of this turtle, which was the subject of his research.

According to conventional wisdom, no reptilian egg should survive being immersed in water. However, in contrast, it turns out that for brahminy river turtles, it is a necessary condition for their development. The key to successful breeding was to mimic the water regime of North Indian rivers. The eggs spent a month and a half in a water bath, then three months in the dry and cold, then two months in the warmth, and finally a brief spell in the water again, where the lively hatchlings broke out of the shell in a flash.

Thanks to this simulation we can reconstruct the natural process of the brahminy river turtle’s egg incubation. She lays her eggs in the autumn in flooded shallows. When the water level drops with the onset of winter, the eggs end up covered with debris on land, but must wait until the warmer spring months to develop. During this time, the embryos develop rapidly so that they are ready to hatch after being inundated by the monsoon flood in June. This is a fundamental finding – if dams are built on the rivers where the turtle lives and the water level remains constant, this turtle would become extinct.