In April 2021, when the Vennaru River, a tributary of the Cauvery, was at its ebb under the summer sun, a team of researchers searched the waters for the Cantor’s giant softshell turtle (Pelochely scantorii), a species on the brink of extinction. It was a year into the pandemic, and fieldwork was slow, but the search continued. Then suddenly, a turtle surfaced, took a breath, and dived back in.
“At first, we thought we found what we were looking for,” says Ecologist Peter Christopher R, who was part of the team of independent researchers working along with the state forest department on the project. The team members photographed the turtle and sent it to Deepak Veerappan, the lead researcher. “We were stunned when he told us it was not Cantor’s giant but something rarer, the Leith’s softshell turtle (Nilssonia leithii), a critically endangered species, endemic to South India and that has not been recorded in the region for three decades,” says Peter.
Over the next few weeks, says Veerappan, the team saw Cantor’s giant softshell turtles, Indian flap shell turtles, marsh crocodiles, and otters in the Cauvery. Between 2022 and 2023, the team, led by Jason D Gerard, Veerappan, and Raman Kothandapani, expanded the research. “The major difference between the two large softshell turtles found in the region is the distinct head shape. Leith softshell has a distinct sharp head and a pig-like nose with orangish-red marking behind the eyes extending to the head. The head of a Cantor’s softshell turtle is shaped like a large frog and the mouth is flat,” says Gerard.
“We did not expect to find the species in this location as it has not been seen for 30 years,” says Gerard. “Rivers are so polluted that they are becoming more uninhabitable for aquatic animals. So, we were thrilled to see the turtle living in a heavily human-dominated landscape. They were confined to small pools located sporadically along the river.”
Aquatic life has dwindled in the rivers here because of pollution, habitat destruction, and human encroachment, say researchers. “These turtles help maintain freshwater ecosystems,” says Christopher, who adds that the team is involved in the conservation of these endangered chelonians in the rivers of Tamil Nadu with the support of the forest department. The researchers have organised awareness programmes for the local communities and in schools in the surrounding areas. Ecologists are also trying to bring in situ conservation with the support of the forest department, to protect nests in their natural habitats and release hatchlings into the river.
Some people in the local fishing community occasionally eat these turtles, believing that the meat has medicinal qualities. “The people here were not aware there were two species. They thought one was male and the other female,” says Christopher. One fisherman told the researchers that when the turtles are caught in their nets, they flip them upside down onto the sandbanks, as these turtles get entangled in the nets and damage them.
“These turtles are primary consumers and feed on aquatic invertebrates, small fish, and plants, which helps regulate populations of their prey species. The feeding habits of these turtles include scavenging and predation, which help in nutrient cycling, thus contributing to water quality,” says Christopher. “The life cycle of these turtles takes place in fresh water. They breed underwater, and females lay eggs on sandbanks. Though these turtles are not often sighted, once out they can be easily spotted due to their large size.” Adults grow to 2ft to 3ft in size. “They grow to be as big as their more famous marine cousins, the olive ridleys,” says Christopher.
Between 2022 and 2023, the team studied the population status of Leith’s softshell turtle in the Cauvery, within the Cauvery South Wildlife Sanctuary, focusing on the Melagiri region in TN. During this study, they recorded more than 30 turtles, indicating the presence of a viable breeding population within the sanctuary. “These turtles are also poached for their meat, which locals believe is a cure for piles, in unprotected regions of TN. Though the Vaigai River is drought-prone, there are earlier records of the turtles in the river. Sightings were recorded in 2009,” says Deepak. He adds that though they can also be bred in captivity like the olive ridleys, there aren’t any breeding programmes for this species in the country.
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