Frogs also communicate by smell rather than vocal

Frogs have long been known as great vocal communicators, but Australian biologists on Wednesday found evidence that they also communicate by smell.

The researchers from the University of New South Wales in Sydney of Australia examined two species of large, ground-dwelling frogs, the great barred frog (Myxophyes fasciolatus) and the striped marsh frog (Lymnodynastes peronii).

The researchers used a series of choice trials to determine whether individuals were attracted to the odors or to other frogs, and if individuals were sensitive to the predation risks associated with these odor accumulations.

In a controlled arena, the frogs were given a choice of sand-filled plastic containers as shelter.

The containers were scented differently each time, sometimes with the frog's own scent, sometimes with the scent of another frog of the same species, and sometimes with the scent of the striped swamp frog, L. peronii.

The great barred frogs showed that they were attracted to all frog scents, and generally preferred the scented shelter as compared to the unscented.

When the scent of a red bellied black snake was introduced, the male frogs preferred another site with the scent of another individual of its own species.

According to Associate Professor Peter Banks of the University of New South Wales in Australia, until now, scientists had largely ignored olfactory communication in frogs, while concentrating on the more obvious vocal signals.

He, who is a co-author on the paper, said decision making on an olfactory basis had not been proved in frogs before.

"Lots of people have focused on their auditory communication, their calls, because that's the most conspicuous thing," he told ABC News on Wednesday.

"But frogs have very sensitive skin and they're very sensitive to chemicals in the environment. So it was only logical that adult frogs would be picking up on chemical information such as odor marks or scent marks; but no-one else had (demonstrated) it."

"It's not really that surprising, when you think about it, given the physiology of the animals and the way they behave. They' ve got preferred sites that they call from, and they'll be leaving chemical traces behind in those spots."

Banks said the research creates a whole range of fresh questions.

"What information might be in these marks? Is it just that it smells like another frog, are there signs of individuality in there, is there information about the breeding status of the animals that are there? How exactly are they using that information?" he said.

The paper has been published in The Royal Society's Biology Letters on Wednesday.

Source: China.org.cn - China news