Elephants can distinguish familiar from other species through vibrations generated in the soil. Photo:
Reading aloud Elephants are able to differentiate familiar and unfamiliar conspecifics from the vibrations they create with their trunks in the ground. These are very deep, inaudible to humans sound waves that can spread for miles across the earth's surface. For example, the animals warn each other of dangers. The elephants, however, do not respond to all such sound waves, have now been observed American researchers: they seem to be able to recognize who the waves come from, and react only when the sounds of familiar conspecifics are generated. Elephants use their proboscis to hear sounds in the infrasound area? this is below the audible pitches? which are transmitted both over the air and through the ground. The animals can perceive the sound waves transmitted through the floor with special cells in their legs and trunks. Earlier, researchers had observed that elephants can communicate via such infrasound sounds.

To further investigate this ability, the researchers now made warning calls from elephants in Kenya and Namibia, with which the animals warn each other of lions. They transformed them into infrasonic waves and played them to Namibian elephants, who were drinking at a waterhole. These animals responded to the warning calls of Namibian elephants by stiffening, crowding and a quick exit from the water hole. The sound waves of the Kenyan elephants, however, they perceived true, but hardly responded to it. Similarly, the animals ignored artificially created vibrations that had similar characteristics as the recorded sound waves.

Why the elephants react differently to the sound waves of different conspecifics, the researchers do not yet know. However, they suspect that the animals trust only those sounds that they can assign to known elephants. They probably protect themselves from falling for false warnings, because every flight costs the animals precious energy.

Science, online service Original text: Caitlin O'Connel-Rodwell (Stanford University, Palo Alto) et al .: Journal of the Acoustical Society of America, August issue ddp / science.de? Tobias Becker advertisement

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