By Jyotsna Singh
BBC News, Delhi
The nest-making frogs are believed to be "very rare"
A scientist in India says he has found three rare species of frogs that make nests in which to lay their eggs.
Dr SD Biju of Delhi University says the frogs make nests after laying eggs to protect them from heat and predators.
The discovery was made in the rainforests of the Western Ghats mountain range in the southern Indian states of Kerala and Karnataka.
It comes after 20 years of intensive research carried out in Wayanad in Kerala and Coorg in Karnataka.
The tiny frogs, which measure up to 12cm (about five inches) in length, roll leaves from top to bottom to make a cocoon and produce a sticky substance to close the ends to secure the eggs.
"These are extremely rare frogs, the only ones of their kind found in Asia," Dr Biju told the BBC.
He said the frogs differed from leaf-nesting frogs found in America and Africa as they make their nests after the females have laid the eggs.
The American and African species build the nest in the process of laying eggs, and both male and female frogs build it together.
Dr Biju says the species are seriously threatened by coffee and other plantations due to which they are losing their habitat in the forest.
"Eight years ago when I visited the area it was easy to spot them breeding during the night. But there has been a dramatic change and it's now extremely rare to spot them," he says.