Why Do Cats Purr? Meow We Know Kittens, Feral Cats Cry Because Of Hunger And Health Risks

A recent survey by the Humane Society of the United States estimated that there are 86.4 million owned cats in the country, with most owners taking care of more than one feline in their homes.

Americans love their pets, but cats, in particular, appear to have some sort of hidden agenda. We know cats love to sleep on couches and have their chins scratched, but new scientific evidence points to the possibility that our beloved kittens may be moonlighting as bloodthirsty predators.

First, though, it’s important to understand what cats are trying to convey with their vocal communications. Pet owners have long assumed cats purr because they are happy -- and while that may be true, it is also a bit misleading. Veterinarian Kelly Morgan told WebMD that purring is a method of self-healing that may be a remedy for either fear or hunger, which may explain why cats sometimes purr en route to their vets' offices.

“People will smile when they’re nervous, when they want something, and when they’re happy, so perhaps the purr can also be an appeasing gesture,” Morgan said.

The vocalization signal originates in the brain and is then sent to the laryngeal muscles, causing them to twitch at a rate of 25 to 150 vibrations per second. The purr emits when vocal cords rub together during inhalation and exhalation.

The smug superiority complex so many cats seem to exhibit is actually grounded in reality, according to Karen McComb, who told Mother Nature Network that they are exploiting “innate tendencies in humans to respond to crylike sounds in the context of nurturing offspring.”

While indoor kitties are wooing their owners with meows and purrs, humans should start paying more attention to feral cats. A recent study published in the peer-reviewed public health journal Zoonoses and Public Health found that stray cats are a dangerous source of diseases, including plague, rabies, and toxoplasmosis, the latter of which can cause flulike symptoms in humans, as noted by George Fenwick, the president of the American Bird Conservancy, in an op-ed for the Sun in Baltimore.

Feral cats are the animals most frequently responsible for human infection with rabies, a number that could account for one-third of cases. In 2008, the number of rabid cats was four times that of rabid dogs. And in 2010, Fenwick reported, rabies cases fell for all domestic animals except cats.

To combat widespread plague, and the mysterious death of countless birds victimized by hungry furballs, local governments across the U.S. have instituted plans for the treatment and adoption of feral cats -- or their euthanization. In a column for the Tampa Bay Times in St. Petersburg, Fla., Dan DeWitt advised animal lovers to make sure the cat population keeps purring.

“The national [feline] population has tripled in the past 40 years, partly because they are more popular as pets, partly because more people are feeding colonies of feral cats,” DeWitt wrote. “In fact, I think we agree on just one thing: that irresponsible pet owners are the ultimate cause of all the unnecessary deaths of cats and wildlife. To their credit, cat lovers and organizations full of them, such as the Humane Society of the Nature Coast, already try to spread this message.”