Biologists have discovered that red-eyed tree frogs, which are typically found in Central and South America, can send warnings to each other by rapidly shaking the branches of trees.
They found that male frogs "pluck" branches with their back legs around 12 times per second to create vibrations designed to warn off competitors they feel might be encroaching on their territory.
Nearby frogs detect the vibrations through their legs and often respond with vibrations of their own.
The researchers believe the tree frogs may also use vibrations to send other messages to each other such as attracting potential mates and even sending warnings about threats from predators.
Until now insects were thought to be the only species which could communicate using vibrations through plants. The findings suggest that scientists may have been overlooking a crucial form of communication among animals by focusing on calls and visual displays when studying animal behaviour.
Dr Michael Caldwell, a biologist at Boston University who led the research on tree frogs, said subtle variations in the vibrations conveyed information about the size, status and motivation of the frogs producing the signals.
He said: "Although we rarely study the use of vibrations, most animals are sensitive to substrate vibrations. That said, frogs are extremely sensitive to substrate vibrations.
"Vibrations travel from the substrate into the body, and travel by bone conduction to the middle ear. The frog uses the same middle ear organ to detect vibrations as it uses to hear sound.
"From the results of staged contests and analysis of the vibrations themselves, we can infer that they convey information about the status and motivation of signallers as well as about signaller size."
Many species of frogs have been found to bob or shake during aggressive displays to warn off competitors or while calling, but such behaviour was often thought to be a visual stimulus to make the frogs appear larger.
Dr Caldwell and his colleagues used a mechanical shaker to simulate a frog shaking a branch and watched the responses of frogs at the other end of the same branch.
They found at frequencies of around 12 times per second, the frogs began to respond as they would in the wild.
Frogs also responded to vibrations produced by competitors even when the frogs were not visible to each other, suggesting the frogs were getting information from the vibrations that was not contained in visual displays.
The researchers also found differences in the vibrations produced by individual frogs according to how close a competitive male was, how big they were, how powerful it was and what their intentions were.
In their tests they found the red-eyed tree frogs could detect vibrations up to two metres away, but the vibrations travel much further and may still be detected further away.
Other work by the same group has suggested that these frogs may come hard-wired with the ability to detect and interpret vibrations.
Dr Caldwell found that even as embryos in their eggs, red-eyed tree frogs can tell the difference between rainfall on the leaf where clutches of eggs are laid and the movement of a snake that will prey on them.
On detecting the vibrations produced by a snake, the tadpoles emerge early from their eggs and drop into nearby water to escape from the predator. Rainfall on the branch, however, does not trigger such a response.
Female South Asian common tree frog is thought to use rhythmical toe tapping to attract mates while male leaf frogs called Cruziohyla calcarifer also produce bobbing actions on leaves to ward off other males invading their territory.
Researchers now believe vibration and haptic sensations may provide a valuable new way of studying the animal kingdom.
Elephants, for example, have been found to capable of detecting low frequency seismic signals that travel through the ground when they make their low, rumbling calls. They use their trunks and feet to detect the vibrations.
Andrew Gray, a herpetologist at the University of Manchester who has studied leaf frog communication, said: "Some frogs don't make loud calls and some don't call at all and so vibration may be a way of overcoming that.
"Both red-eyed tree frogs and Cruziohyla calcarifer have black lines on their flanks so when they move up and down it creates an optical illusion that makes them seem bigger, but sometimes they are in quite dense foliage so they might not be able to see each.
"They are on the same tree and branch, so the vibrations will travel through the plant and they can pick up on that too."