Purr

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A domestic cat purring
A different domestic cat purring
Different cats can sound somewhat different when purring.
Purring and meowing
Domestic cat purring mixed with pronounced meowing
Guinea pig producing purring-like sound
This sound is made when a guinea pig is content, examples of this include when it is being petted or held, when groomed, investigating a new place, or given food. It is neither continuous nor does it correspond to respiration, and thus is not a true purr.
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A purr or whirr is a tonal fluttering sound made by some species of felids, including both larger, wild cats and the domestic cat (Felis catus), as well as two species of genets. It varies in loudness and tone among species and in the same animal. In smaller and domestic cats it is known as a purr, while in larger felids, such as the cheetah, it is called a whirr. [1]

Contents

Although true purring is exclusive to felids and viverrids, [2] other animals such as raccoons produce vocalizations that sound similar to true purring. Animals that produce purr-like sounds include mongooses, kangaroos, wallabies, wallaroos, badgers, rabbits and guinea pigs.[ citation needed ]

Animals purr for a variety of reasons, including to express happiness or fear, and as a defense mechanism. It has also been shown that cats purr to manage pain and soothe themselves. [3] Purring is a soft buzzing sound, similar to a rolled 'r' in human speech, with a fundamental frequency of around 25 Hz. [4] This sound occurs with noticeable vibrations on the surface of the body, varies in a rhythmic pattern during breathing and occurs continuously during inhalation and exhalation. The intensity and length of the purr can also vary depending on the level of arousal of the animal. [4]

Mechanism

The mechanism by which cats purr is an object of speculation, with different hypotheses proposed. An early idea was that purring is a hemodynamic process where sound is produced as the blood runs through the thorax. [5]

There is a unique "neural oscillator" in the cat's brain of uncertain significance. [6] Although the mechanism has not yet been fully explained, recent studies have inferred it could be the result of oscillatory mechanisms in the central nervous system. [7]  Studies have also shown that purring can be caused through electrically stimulating the infundibular region of the cat's brain, suggesting central control. [8]

Vocal folds/laryngeal muscles

One hypothesis, backed by electromyographic studies, is that cats produce the purring noise by using the vocal folds or the muscles of the larynx to alternately dilate and constrict the glottis rapidly, causing air vibrations during inhalation and exhalation. [9] Combined with the steady inhalation and exhalation of air as the cat breathes, a purring noise is produced with strong harmonics. [10]

Degree of hyoid ossification

No cat can both purr and roar. The subdivision of the Felidae into "purring cats" (Felinae) on one hand and "roaring cats" (Pantherinae) on the other goes back to Owen [11] and was definitively introduced by Pocock, [12] based on whether the hyoid bone of the larynx is incompletely ("roarers") or completely ("purrers") ossified. However, Weissengruber et al. argued that the ability of a cat species to purr is not affected by the anatomy of its hyoid. [13]

The "roaring cats" (lion, Panthera leo; tiger, P. tigris; jaguar, P. onca; leopard, P. pardus) have an incompletely ossified hyoid, which, according to this hypothesis, enables them to roar but not to purr. However, the snow leopard (Uncia uncia, or P. uncia), as the fifth felid species with an incompletely ossified hyoid, purrs. [14]

All remaining species of the family Felidae ("purring cats") have a completely ossified hyoid, which enables them to purr but not to roar. Based on a technical acoustic definition of roaring, the presence of this vocalization type depends on specific characteristics of the vocal folds and an elongated vocal tract, which is rendered possible by an incompletely ossified hyoid.

Frequency, amplitude, and respiratory variation

Purpose

In domestic cats, many signals that occur when interacting with humans seem to originate from when the animal was dependent on the mother. Cats have been observed to purr for most of their lifespan, starting from when they were young and suckling from their mother. [19] Purring may be a signaling mechanism of reassurance between mother cats and nursing kittens. Post-nursing cats often purr as a sign of contentment when being petted, becoming relaxed or eating. Some purring may be a signal to another animal that the purring cat does not pose a threat.

Cats have been shown to have different types of purrs depending on situations. For example, purring appears to be a way for cats to signal their caretakers for food. This purring has a high-frequency component not present in other purrs. These are called solicitation purrs (when the cat is seeking a result) and non-solicitation purrs, and the two are distinguishable to humans. In a study, 50 humans were subjected to playbacks of purrs recorded in solicitation and non-solicitation situations at the same amplitude. Humans regularly judged the solicitation purrs as less pleasant and more urgent than the non-solicitation purrs. [19]  This variety of purring seems to be found more frequently in cats in a one-to-one relationship with a caretaker. Similarities have been drawn between an infant's cry and the isolation cry of domestic cats. The high-frequency aspect of the purr may subtly exploit humans' sensitivity to these cries. Using sensory biases in communication between species provides cats with a productive means of improving the care that they receive. [19]

Cats often purr when distressed or in pain, such as during the three stages of labor. In the first stage, the uterus begins to contract, the cervix relaxes, the water breaks and the cat begins to purr. The female cat (queen) will purr and socialize during the first stage of labor. The purring is thought to be a self-relaxation technique. [20]

See also

References

  1. ↑ "Felinae", Wikipedia, 9 October 2024, retrieved 26 October 2024
  2. ↑ Peters, G. (2002). "Purring and similar vocalizations in mammals". Mammal Review. 32 (4): 245–271. doi:10.1046/j.1365-2907.2002.00113.x. ISSN   1365-2907.
  3. 1 2 "What Makes A Cat Purr". purina.com.au. Retrieved 18 November 2019.
  4. 1 2 Sissom, Dawn E. Frazer; Rice, D. A.; Peters, G. (1991). "How cats purr". Journal of Zoology. 223 (1): 67–78. Bibcode:1991Natur.349Q.460.. doi:10.1111/j.1469-7998.1991.tb04749.x. ISSN   1469-7998. S2CID   32350871.
  5. ↑ Schötz, Susanne; van de Weijer, Joost; Eklund, Robert (29 August 2019). "Melody matters: An acoustic study of domestic cat meows in six contexts and four mental states". doi: 10.7287/peerj.preprints.27926v1 .{{cite journal}}: Cite journal requires |journal= (help)
  6. ↑ "Why and how do cats purr?". Library of Congress . Retrieved 10 April 2011.
  7. ↑ Remmers, J. E.; Gautier, H. (1 December 1972). "Neural and mechanical mechanisms of feline purring". Respiration Physiology. 16 (3): 351–361. doi:10.1016/0034-5687(72)90064-3. ISSN   0034-5687. PMID   4644061.
  8. ↑ Gibbs, E. L.; Gibbs, F. A. (1936). "A purring center in the cat's brain". Journal of Comparative Neurology. 64 (2): 209–211. doi:10.1002/cne.900640203. ISSN   1096-9861. S2CID   84375344.
  9. ↑ K.M. Dyce, W.O. Sack and C.J.G. Wensing in Textbook of Veterinary Anatomy 3rd Ed.2002, Saunders, Philadelphia; p156
  10. ↑ "How A Puma Purrs". Archived from the original on 22 January 2013.
  11. ↑ Owen, Richard (1834). "On the Anatomy of the Cheetah, Felis jubata, Schreb". The Transactions of the Zoological Society of London. 1 (2): 129–136. doi:10.1111/j.1096-3642.1835.tb00611.x.
  12. ↑ Pocock, R.I. (1916). "On the hyoidean apparatus of the lion (F. leo) and related species of Felidæ". Annals and Magazine of Natural History. 18 (104): 222–229. doi:10.1080/00222931608693839.
  13. ↑ Weissengruber, G. E.; Forstenpointner, G.; Peters, G.; Kubber-Heiss, A.; Fitch, W. T. (2002). "Hyoid apparatus and pharynx in the lion (Panthera leo), jaguar (Panthera onca), tiger (Panthera tigris), cheetah (Acinonyx jubatus) and domestic cat (Felis silvestris f. catus)". Journal of Anatomy. 201 (3): 195–209. doi:10.1046/j.1469-7580.2002.00088.x. PMC   1570911 . PMID   12363272.
  14. ↑ Hemmer, Helmut (1972). "Uncia uncia". Mammalian Species (20): 1–5. doi: 10.2307/3503882 . JSTOR   3503882.
  15. ↑ Eklund, Robert, Gustav Peters & Elizabeth D. Duthie. 2010. An acoustic analysis of purring in the cheetah (Acinonyx jubatus) and in the domestic cat (Felis catus) Archived 14 February 2019 at the Wayback Machine , Proceedings of Fonetik 2010, 2–4 June 2010, Lund University, Lund, Sweden, pp. 17–22.
  16. ↑ Schötz, Susanne & Robert Eklund. 2011. A comparative acoustic analysis of purring in four cats Archived 16 November 2020 at the Wayback Machine . Proceedings of Fonetik 2011, 8–10 June 2011, Royal Institute of Technology, Stockholm, Sweden, pp. 9–12.
  17. ↑ Eklund, Robert, Gustav Peters, Florian Weise & Stuart Munro. 2012. A comparative acoustic analysis of purring in four cheetahs Archived 2 November 2013 at the Wayback Machine , Proceedings of Fonetik 2012, 30 May–1 June 2012, Gothenburg University, Gothenburg, Sweden, pp. 41–44.
  18. ↑ Eklund, Robert & Gustav Peters. 2013. A comparative acoustic analysis of purring in juvenile, subadult and adult cheetahs Archived 20 August 2020 at the Wayback Machine . In: Robert Eklund (ed.), Proceedings of Fonetik 2013, the XXVIth Swedish Phonetics Conference, Studies in Language and Culture, no. 21, ISBN   978-91-7519-582-7, ISBN   978-91-7519-579-7, ISSN 1403-2570, pp. 25–28.
  19. 1 2 3 McComb, Karen; Taylor, Anna M.; Wilson, Christian; Charlton, Benjamin D. (14 July 2009). "The cry embedded within the purr". Current Biology. 19 (13): R507 –R508. Bibcode:2009CBio...19.R507M. doi: 10.1016/j.cub.2009.05.033 . ISSN   0960-9822. PMID   19602409. S2CID   10972076.
  20. ↑ "Birth Difficulties Symptoms - Cats | petMD". www.petmd.com. Retrieved 18 November 2019.

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