How horses recognise each other

Researchers in England have shown that horses, just like humans, use both sound and image in order to recognise each other. This was done by combining the sight on a horse with a sound of the same horse or another horse.
Researchers of University of Sussex (England) performed the tests with a group of 24 horses. The neighing of individual animals was recorded on tape. The test was performed by letting a horse belonging to the same group disappear behind a partition and playing either the sound of this animal or the sound of another. the reaction of the horse to be studied was determined by looking at how fast and how long the animal looked at the speaker.
When the sound did not match the image, the horses looked at the speaker faster and longer. What they heard was not what they expected to hear.

The results suggest that horses, like humans, use a ‘cross-modal’ system for recognition. In this system, different senses - in this case sight and hearing - are used in order to recognise others.
Recognising other members of the same species is a complex process that still poses a lot of questions. The researchers hope that this test can also be used in other species to find out more about this fascinating process.
The results of the test are published in the “Proceedings of the National Academy of Sciences of the United States of America”.