Smooth-coated otters seen near Mukkombu after a long break

Known as neer naai (aquatic dogs) in Tamil, the animal plays an important role in controlling the population of fish in rivers

A search for a migratory stork in the Upper Anaicut near Mukkombu (on the road leading to the Butterfly Park) turned up another surprise visitor instead for the city’s nature lovers recently — the smooth-coated otter, a freshwater fish-loving animal that hasn’t been seen along the Cauvery river stretch for many years.

“We thought they were crows at first, but when we looked more closely, we realised it was a group of eight smooth-coated otters rolling around on the sandbank,” said A. Relton, associate professor and head, Department of Social Work, Bishop Heber College, who was part of the team led by the institution’s Nature Club on Sunday.

When spotted, the otters were rubbing themselves with ‘spraint’ or their own faeces, which is a peculiar part of the animals’ grooming behaviour and a means of olfactory communication, Mr. Relton told The Hindu.

Listed as ‘Vulnerable’ on the IUCN Red List, the animals commonly occur in shallow and placid waters such as wetlands and seasonal swamps, rivers, lakes, and rice paddies. They are active during night and day, and are strong swimmers.

Known as neer naai (aquatic dogs) in Tamil, the animal plays an important role in controlling the population of fish in rivers, said Mr. Relton. “Even though humans are fishing commercially, otters do this naturally. In fact the human impact of overfishing and depletion of water resources has caused the disappearance of smooth-coated otters from the freshwater bodies in the country,” he said. The animals are also illegally hunted for their pelt.

In the Cauvery delta, the drying out of riverbeds in recent years has driven away these animals. Significantly, the countrywide population of the otters remains undocumented.

Video clips shared by the Nature Club showed the otters swimming in the river in V-formation, led by a dominant male. “We identified four young and three females in the group. The swimming method is meant to narrow down the fishing area and prevent fish from escaping,” he said.