The red fox (Vulpes vulpes) is the world's most widespread beast of prey. Its natural range extends throughout Europe, Asia, North America and, in part, Africa and Australia. Even though this furry carnivore is popular for its keen senses, little is known about its sensory abilities. So, it was necessary to "look at the tooth" and find out how it really is with that sharpness. This task was undertaken by a scientific team together with Professor Hynek Burda from the CULS Faculty of Forestry and Wood Sciences.
The fox is primarily a dusk and nocturnal hunter, who must rely mainly on hearing to obtain food. The voles that make up the main part of fox diet often occur in thick grass, under leaves or under snow, and must be located by ear. When fox manages to pick up the sound signals, it surprises prey from a very distant place, prey that no longer has a chance to escape from fox clutches.
There is no ambiguity in how the fox and other beasts intercept the sound signals. They turn their well-developed ears and look for the direction from which they hear the sound – the strongest signal – best. But how sensitive is his hearing and what frequencies of sound can fox perceive? This finding was the aim of an experiment for which a special portable chamber was constructed in which three young tame foxes were tested.
The chamber used for testing the fox's hearing and determining the hearing thresholds was equipped with a loudspeaker, from which the foxes were presented with audio signals of various frequencies and intensities. The fox was first trained to wait for an audible signal (clear tone), after which it could leave the "waiting room" and in the second part of the chamber choose a treat from the automatic dispenser. If she left the waiting room before the tone sounded, she was "punished" by not receiving any reward and had to wait longer for another chance. After the fox had learned the task, tones of various frequencies and intensities were played to it, and the fox's reactions were evaluated on film and computer recordings – that is, what tones and at what intensity the fox had heard or no longer heard. Thus, the first known complete audiogram of a fox could be compiled.
It turned out that the fox has a hearing range of almost 10 octaves, from 51 Hz to 48 kHz, and the range and sensitivity of its hearing combines the hearing abilities of a dog and a cat. The overall conclusion is that the absolute sensitivity of fox hearing is one of the best that has been described in mammals so far, and the proverbial acumen is not just a myth.
prof. RNDr. Hynek Burda, CSc.
In 1976 he studied biology at Charles University in Prague. From the same year until 1984 he worked as a researcher at the Institute of Experimental Medicine in Prague and then as an associate professor of zoology at the University of Zambia until 1986. He was also an employee of the Department of Zoology and an assistant professor at the Goethe Medical Faculty of the University of Frankfurt and a professor of general zoology in Essen, Germany. He currently works as a professor and head of the department at the Faculty of Biology of the same university and at the Faculty of Forestry and Wood Sciences of the CULS in Prague. The subject of his research is sensory ecology, especially hearing and magnetoreception of mammals.
Prepared by: Jakub Málek