14 July 2009

Cats purr you out of bed

A new British study suggests that smart housecats quickly learn that their particular cry-purr combination is the most effective in getting bleary-eyed humans to do their bidding.


It's 6 am. Your cat has jumped up on the bed and, as he does every morning, lets out a mix of low purr and plaintive cry. The message is irresistible: Get up now and feed me.

A new British study - involving participants with names like Fuzzy, Marbles and Socks - suggests that smart housecats quickly learn that this particular cry-purr combination is the most effective in getting bleary-eyed humans to do their bidding.

"Remember, these cats have years to train up their owners," said study author Karen McComb, a specialist in animal vocal communication in the department of psychology at the University of Sussex. "They learn to dramatically exaggerate this cry embedded within the purr because it proves effective in getting their owner to respond."

Cats have rich vocabulary
The study suggests that Felis catus domesticus has a richer vocabulary than the standard "meow," and modulates its vocalizations to express contentment (purr), alarm (shrieking meow) or insistent persuasion (the cry-purr).

"They are trying to communicate," said one expert, Dr Tony Buffington, professor of veterinary clinical services at Ohio State University Veterinary Hospital, Columbus. He called the study, "a wonderful idea to follow-up on - it's going to open up a lot more understanding of cats in general."

The idea for the study, published in the July 14 issue of Current Biology, came from McComb's own cat, Pepo.

Cats develop behaviour towards their owners
"He consistently woke me up in the morning with a very insistent purr; it was very difficult to ignore. And he continued until he was fed," she said. Although McComb's prior work had centred on animals as exotic as the elephant or lion, it got her to thinking - why was this particular vocalisation so compelling? "I wanted to get to the bottom of it."

She quickly found out that domestic cats only emit the cry-purr combo in the presence of a long-time human companion. "It's a behaviour cats develop with particular owners," McComb said. So, she had a variety of people interact with their cats and record the morning "solicitation call," as well as other purrs. McComb's team then had strangers listen to, and rate, all those recorded vocalizations.

"It turned out that the purrs that were getting the highest score on urgency and unpleasantness were ones that had an embedded cry, given at a higher level," McComb said. "It rises above the energy in the normal purr." In fact, when McComb's team digitally removed the cry from the recorded purr, it lost its sense of urgency for the people who heard it.

Cry-purr better than purr alone
This was the sound that Pepo used to his advantage to get McComb to fill his dish each morning, and it seems to have caught on throughout the domestic cat world. According to McComb, the cry-purr appears to work better at rousing humans than either a purr alone ("you're more likely to just drop off to sleep again") or the standard meow ("I think that is likely to get the cat ejected from the bedroom").

McComb also speculates that the use of a plaintive cry wrapped inside a purr taps into a deeply human response to another early-morning feeder - babies. "Parallels have been drawn between the cry of domestic cats and that of human infants," her team notes in the study. Embedding a cry in the purr "could serve as a subtle means of exploitation, tapping into an inherent mammalian sensitivity to such cries," they wrote.

Whatever the reason, other experts agree that cats are adept communicators.

"We all know as veterinarians that cats are a unique species, with a keen ability to get what they want from people," said Dr Leilani Alvarez, a veterinary acupuncturist in Bedford Hills, New York. "My feline patients guide me much more in choosing the points I needle than my canine patients do. They vocalise in unique ways that clearly communicate when a point doesn't agree with them - it's not a hiss or a growl, it's hard to describe, but I hear it repeatedly and it's actually quite helpful."

Are cats manipulative?
For his part, Buffington wonders if McComb has only hit the tip of the iceberg when it comes to cats' ability to get particular messages out.

"One wonders how widespread these behaviours are - is it specific to food, or do cats use the [vocalisations] for a variety of other things? They may well have a whole variety of signals and behaviours they use to try and get our attention," he said.

And why do humans put up with such blatant manipulation? According to McComb, a cat's insistence on getting its needs met, now, might be one of the things that draws humans to them.

"Cats are really quite effective in getting humans to do what they want," she said, "and we certainly tolerate it because it goes along with all those independent elements of cats, where they just go along and do their own thing." –(EJ Mundell, HealthDay News, July 2009).


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