Instruct: Given a question, retrieve passages that can help answer the question.
Query: Can cats control their purr?
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.[2] Combined with the steady inhalation and exhalation of air as the cat breathes, a purring noise is produced with strong harmonics.[3]
The mechanism of how cats purr is elusive. This is partly because cats do not have a unique anatomical feature that is clearly responsible for this vocalization. One hypothesis, supported by electromyographic studies, is that cats produce the purring noise by using the vocal folds and/or the muscles of the larynx to alternately dilate and constrict the glottis rapidly, causing air vibrations during inhalation and exhalation. Combined with the steady inhalation and exhalation as the cat breathes, a purring noise is produced with strong harmonics. Purring is sometimes accompanied by other sounds, though this varies between individuals. Some may only purr, while other cats also emit low level outbursts sometimes described as "lurps" or "yowps".
It was once believed that only the cats of the genus "Felis" could purr. However, felids of the genus "Panthera" (tigers, lions, jaguars and leopards) also produce sounds similar to purring, but only when exhaling. The subdivision of the Felidae into ‘purring cats’ on the one hand and ‘roaring cats ’ (i.e. non-purring) on the other, originally goes back to Owen (1834/1835) and was definitely introduced by Pocock (1916), based on a difference in hyoid anatomy. The ‘roaring cats’ (lion, "Panthera leo"; tiger, "P. tigris"; jaguar, "P. onca"; leopard, "P. pardus") have an incompletely ossified hyoid, which according to this theory, enables them to roar but not to purr. On the other hand, the snow leopard ("Uncia uncia"), as the fifth felid species with an incompletely ossified hyoid, purrs (Hemmer, 1972). All remaining species of the family Felidae (‘purring cats’) have a completely ossified hyoid which enables them to purr but not to roar. However, Weissengruber et al. (2002) argued that the ability of a cat species to purr is not affected by the anatomy of its hyoid, i.e. whether it is fully ossified or has a ligamentous epihyoid, and that, 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, the latter rendered possible by an incompletely ossified hyoid.
Sir Purr, an anthropomorphic black cat who wears a jersey numbered '00', has been the Panthers' mascot since their first season. During games, Sir Purr provides sideline entertainment through skits and "silly antics". The mascot participates in a number of community events year-round, including a monthly visit to the patients at Levine Children's Hospital. Sir Purr also hosts the annual Mascot Bowl, an event which pits pro and college mascots against each other during halftime at a selected Panthers home game.
It has been postulated that domestic cats can learn to manipulate their owners through vocalizations that are similar to the cries of human babies. Some cats learn to add a purr to the vocalization, which makes it less harmonious and more dissonant to humans, and therefore harder to ignore. Individual cats learn to make these vocalizations through trial-and-error; when a particular vocalization elicits a positive response from a human, the probability increases that the cat will use that vocalization in the future.
Bombay cats are highly social; they tend to be attached to their families and crave attention, and for this reason, cats of this breed are highly suitable for children. Most Bombay cats are not independent. Older Bombays are somewhat more independent than younger ones. They seek attention from their owners and people around them often and dislike being left alone for extended periods of time. Although they like to be around people generally, Bombay cats also tend to have a certain person whom they pay special attention to in their lives. Overall, the Bombay breed is intelligent, playful, and attention-seeking. The Bombay's muscular medium-sized body can be deceiving, as they often weigh slightly more than they might appear to. They don't shed as much as other breeds and require very little grooming. They tend to get along well with other cats, as they have an established pecking order in the household. They have a loud distinctive purr. Bombay cats are known to be vocal and they cry and meow more than other cats.
Purring may have developed as an evolutionary advantage as a signalling 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. The mechanism by which cats purr is elusive. The cat has no unique anatomical feature that is clearly responsible for the sound. It was until recent times, believed that only the cats of the "Felis" genus could purr. However, felids of the genus "Panthera" (tiger, lion, jaguar, and leopard) also produce non-continuous sounds, called "chuffs", similar to purring, but only when exhaling.
The company's evil feline Human Resources director. Although he was originally just supposed to be around for a few strips, the fans named him and demanded more of him. He derives pleasure from seeing employees worry about their jobs, and particularly enjoys tormenting Wally. Merely mentioning the term "layoffs" causes him to purr with delight. Unlike Dogbert, Catbert has no apparent owner, but retains all of the qualities of a cat, and frequently purrs or sheds or performs other acts of "catness", which he uses to torture the employees. He is particularly cooperative and friendly with the Pointy Haired Boss.
Purring may have developed as an evolutionary advantage as a signalling mechanism of reassurance between mother cats and nursing kittens. Post-nursing cats often purr as a sign of contentment: when being petted, becoming relaxed,[4][5] or eating. Some purring may be a signal to another animal that the purring cat does not pose a threat.[6]
Cats rely strongly on body language to communicate. A cat may rub against an object, lick a person, and purr. Much of a cat's body language is through its tail, ears, head position, and back posture. Cats flick their tails in an oscillating, snake-like motion, or abruptly from side to side, often just before pouncing on an object or animal in what looks like "play" hunting behavior. If spoken to, a cat may flutter its tail in response, which may be the only indication of the interaction, though movement of its ears or head toward the source of the sound may be a better indication of the cat's awareness that a sound was made in their direction. 
When cats greet another cat in their vicinity, they can do a slow, languid, long blink to communicate affection if they trust the person or animal they are in contact with. It is a sign of trust. A way to communicate love and trust to your cat from a human perspective is to say their name, and get their attention, and then look them the eyes and slowly blink at them to emulate trust and love, and they may return the gesture.
Bergler, Reinhold "Man and Cat: The Benefits of Cat Ownership" Blackwell Scientific Publications (1989) Bradshaw, John W S "The Behaviour of the Domestic Cat" C A B International (1992) Hobhouse, L T Mind in Evolution MacMillan, London (1915) Turner, Dennis C, and Patrick Bateson. "The Domestic Cat: The Biology of Its Behaviour" Cambridge University Press (1988) Neville, Peter "Claws and Purrs" Sidgwick & Jackson (1992) Neville, Peter "Do Cats Need Shrinks" Sidgwick & Jackson (1990)
Vocalizations of a flat-headed cat kitten resembled those of a domestic cat. The vocal repertoire of adults has not been analyzed completely, but they purr and give other short-ranged vocalizations.
Purring sometimes seems to be a way for cats to signal their caretakers for food. This purring has a high-frequency component not present in other purrs. This variety of purring seems to be found only in cats in a one-to-one relationship with a caretaker.[7]
A purr is a sound in cat communication.
Katy Perry chose to release her own signature fragrance, Purr, to add a personal touch and compete with other celebrities' perfumes; she cited Beyoncé and Kim Kardashian as examples. Having teamed up with Gigantic Parfums, she was actively involved in the development of her fragrance. She mentioned in an interview that she created the product because she loves cats.
Cats often purr when distressed or in pain, such as in labour.[4][8][9][10] This purring may trigger a cat's brain to release a hormone which helps it in relaxing and acts as a painkiller.[11] Purring may also be a healing mechanism to offset long periods of rest and sleep that would otherwise contribute to a loss of bone density. The vibrations and contractions of a purr show a consistent pattern and frequency around 25Hz; these frequencies have been shown to improve bone density and promote healing in animal models and humans.[12][13]
The repressor purR encoded by purR genes controls the synthesis of enzymes involved in purine biosynthesis. A putative 16 bp pur operator was found in the gua promoter. The purR repressor works with other co-repressors, for example guanine which is a co-repressor in "E. coli."
Many cats purr while kneading. They also purr mostly when newborn, when feeding, or when trying to feed on their mother's teat. The common association between the two behaviors may indicate the origin of kneading as a remnant instinct. Some experts consider kneading to "stimulate" the cat and make it feel good, in the same manner as a human stretching.
The brushing of a domestic animal's fur is often perceived as a mark of affection and/or a bonding experience, which can have a soothing effect, e.g. making a cat purr. Special brushes are made for cats and dogs. For an equine's tougher hair, a curry-comb is used.
Domestic cats purr at varying frequencies. One study reported that domestic cats purr at average frequencies of 21.98 Hz in the egressive phase and 23.24 Hz in the ingressive phase with an overall mean of 22.6 Hz. Further research on purring in four domestic cats found that the fundamental frequency varied between 20.94 and 27.21 Hz for the egressive phase and between 23.0 and 26.09 Hz for the ingressive phase. There was considerable variation between the four cats in the relative amplitude, duration and frequency between egressive and ingressive phases, although this variation generally occurred within the normal range.
The "roaring cats" (lion, Panthera leo; tiger, P. tigris; jaguar, P. onca; leopard, P. pardus) have an incompletely ossified hyoid, which according to this theory, 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 (Hemmer, 1972).
Thailand has several cat cafés, most in Bangkok. Cat Cafe by Dome, Cat Up Cafe, Caturday, Cataholic Cafe, The Coffee Cat, Mohu Mohu Cafe and Purr Cat Cafe Club are all located in Bangkok. Each serves baked goods with a small menu of main dishes and coffee and tea. Many have special pricing for petting time with a specific cat. Prices are usually higher than at most cafés but not unreasonably so. They all have rules regarding the behavior of guests towards the cats and often have purebred cats. Catmosphere Cat Cafe and Maewmoth cafés are located in Chiang Mai.
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.
During World War II, "Miss Fury" was painted on the nose of three American warplanes in Europe and the South Pacific. Two of the recurring villains were the Nazi agents Erica Von Kampf and General Bruno. Mills' own white Persian cat Perri-Purr was introduced in the strip, and during World War II Perri-Purr became an unofficial mascot of the American troops.
Since most of the preferred "domestic traits" are neotenous or juvenile traits that persist in the adult, kneading may be a relic juvenile behavior retained in adult domestic cats. It may also stimulate the cat and make it feel good, in the same manner as a human stretching. Kneading is often a precursor to sleeping. Many cats purr while kneading. They also purr mostly when newborn, when feeding, or when trying to feed on their mother's teat. The common association between the two behaviors may corroborate the evidence in favor of the origin of kneading as a remnant instinct.