purr
Purring ( ) is a low-frequency (25 to 150 Hz, domestic cats ≈25 Hz), evenly vibrating noise that cats and some other animals ( e.g. the brown-bristle armadillo ) produce in certain situations. As a rule, it signals well-being, but is also brought about in stressful situations .
Vocalization
Calming factor
The purring of the cat is one of the most famous voiceless vocalizations. Cats already purr after birth, as soon as they are suckled by their mother for the first time. The mother purrs while suckling and so calms the young and herself. The purr indicates to the mother that the kittens are well supplied with milk and are therefore satisfied.
One of the forefathers of cat behavior research, Paul Leyhausen, defined purring as follows: "According to its origin, it is probably a child-like form of sound that indicates to the nursing mother that the young are comfortable". During his research, he found that the kittens keep purring while they are suckling. Likewise, the mother cat continues to purr even when it is dozing or sleeping. In cats of all ages, purring is primarily used to calm down and is considered a signal of peacefulness when cat to cat approach.
Health factor
Leyhausen found out that even sick cats purr as a kind of anticipatory appeasement of a possible attacker. That means cats purr even in stressful situations, such as pain. It is believed that this is for your own reassurance. A basic commonality of all situations that cats purr is that they are in a peaceful mood.
Cats purr at a frequency that aids tissue healing and increases bone density. Accordingly, researchers suspect that purring also triggers a self-healing process.
Sound generation
Frequencies of the purr tones
In general, house cats purr at a frequency of 20 to 30 vibrations per second. Various research results are documented in the Encyclopedia of Scientific Essays, which come to different results in the frequencies of purring. Accordingly, the frequency is predominantly at 27-44 Hz, can fluctuate down to 20 Hz, up to a maximum of 150 Hz.
Origin of the vibration tones
The prevailing scientific opinion assumes that there is a unique neural oscillator in the cat's brain, which, however, has not yet been precisely researched. There are several hypotheses about the generation of sounds and the physiological circumstances in which the purring tones arise; However, the mechanisms have not yet been finally clarified. So far, there has been a complete lack of studies on other animal species that have the ability to produce purrs.
- Larynx hypothesis
- Cats purr is caused by rapid twitching of the larynx muscles and diaphragm. The consequences of the contraction of the larynx muscles narrow and widen the glottis and thus cause the breath to vibrate at low frequencies.
- Hyoid bone hypothesis
- The purring of the cats is generated by the friction of the breath on the hyoid bone . The hyoid bone connects the cat's tongue to the skull . While the hyoid bone is elastic in all large cats , in other cats it is completely ossified. This difference may be the reason why big cats can only purr when they exhale. The other cats can purr continuously as they inhale and exhale.
- Blood flush hypothesis
- The cause of the purr is caused by the appearance of flushing blood in the cat's posterior vena cava, which carries blood from the body to the heart. Since the vein passes through the diaphragm , the blood flow would be compressed there when the muscles move. This creates vibrations that are amplified by the bronchi and the larynx . However, this theory is considered questionable, because in this case dogs or humans should also be able to purr.
- "False vocal cords" hypothesis
- The purring occurs because of two folds of skin called "false vocal cords" that lie behind the cat's real vocal cords. When breathing, these skin folds would vibrate.
See also
Web links
Individual evidence
- ↑ Elizabeth von Muggenthaler: The Felid Purr: A healing Mechanism? ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF) In: J. Acoust. Soc. At the. , Volume 110, Issue 5, November 2001, pp. 2666-2666.
- ↑ Chen et al .: Zhong. Wai Ke Za Zhi . 32, ≈1994, pp. 217-219
- ^ A b Leslie A. Lyons: Why do cats purr? Scientific American, April 3, 2006, accessed January 4, 2016 .
- ^ Paul Leyhausen : Cat's Soul . Essence and social behavior . 2nd Edition. Franckh-Kosmos, Stuttgart 2005, ISBN 978-3-440-09864-6 , pp. 34 .
- ↑ Jan Osterkamp: How and why do cats purr? In: Spektrum.de. June 15, 2015, accessed March 5, 2019 .
- ↑ Eklund, Peters, Duthie: Purring Cheetah Domestic Cat . (PDF) accessed on January 3, 2016
- ↑ Lev Mazniker: Frequency of a Cat's Purr. hypertextbook.com, 2006, accessed January 4, 2016 .
- ↑ Why and how do cats purr? . Library of Congress . Retrieved April 10, 2011.
- ↑ Salomon, Geyer, Gille (Ed.): Anatomy for veterinary medicine . Enke, 2004
- ↑ Purr ... or not just purr ... ( Memento of the original from August 20, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. big-cats.de
