Frogs shake branches to 'talk' to each other

Tree frogs in the rainforest send messages to their fellow humans by snatching branches.

A red-eyed tree frog.Photo: wordpress.com.

Telegraph said Dr. Michael Caldwell - a biologist of Boston University in the US - and colleagues track tree frogs in many tropical forests around the world. They found that males snatched branches with hind legs about 12 times per second to scare animals that came close to their territory. Nearby frogs often respond by snatching branches when they receive the 'message' of their kind.

The team believes that tree frogs also use tree vibrations to send messages to their partners or warnings about the appearance of predators.

Biologists have always thought that only insects can communicate because of the vibrations of trees. Boston University's findings show that scientists are missing out on an important form of communication in the animal world. Usually people only focus on the cries and physical movements of animals when studying them.

Caldwell judged that the sound emitted by the twitching action could provide information about the frog's size, position and engine to produce sound.

'Most animals can feel very slight vibrations and so do tree frogs. The sound came from the vibrations of tree branches transmitted from frog legs to the body, through the skeleton and to the ears , 'he said.

Frogs also respond to the vibrations of competitors despite not seeing each other. This shows that frog tree vibrations contain information that they can understand by ear.

Scientists found many frogs swaying or vibrating their bodies to scare competitors or call their partners. However, they only do so in the opponent's vision, because the vibrating or swaying action makes the opponent feel that their bodies seem larger than they actually are.

Caldwell and colleagues also found that frog's tree twitching movements change according to the opponent's position, body size, strength and intent. In the trials they found that red-eyed frogs often detect the vibrations of tree branches in a distance of up to 2 m. However, the frogs in a farther position can still detect vibrations.