May 14, 2002 -- Is your cat trying to tell you something?
While domestic cats may not know language, a study suggests the animals, which have lived alongside people for thousands of years, have adapted their "meows" to better communicate with humans.
"Cats are obviously very dependent on people for their needs," says Nicholas Nicastro, a graduate student who is working under psychology professor Michael Owren at Cornell University's Psychology of Voice and Sound Laboratory. "I think cats have evolved to become better at managing and manipulating people."
Recording Kitty Calls
One way Nicastro is trying to prove that idea is by analyzing a range of vocalizations of domestic cats and then screening people's reactions to them. To compare his results, he's working on doing the same based on the calls of wild cats.
Nicastro recorded more than 100 different meows from 12 domestic cats (including two of his own). He solicited various sounds from the cats by placing them in different scenarios such as waiting beyond feeding time before feeding them, putting them in empty rooms with the recorder and waiting. He had the owners brush the cats beyond the animals' patience for brushing. And, to record content meows, he simply turned on the recorder "when they were in a good mood."
Then he played the recordings to two sets of people.
He asked the first group of 26 people to rate each meow in terms of how pleasant each sounded. The second group of 28 people was asked to rate each sound in terms of urgency. When he compared people's ratings with acoustical analysis of the meows, he found very clear patterns.
The meows that were rated most pleasant were shorter in duration, had higher frequencies and tended to change from high to low notes. Those rated most urgent were longer in duration, had lower frequencies and often began on low notes and escalated to higher ones. Rarely did a meow receive high marks for both pleasant and urgent.
"The highly urgent calls tended to be the least pleasant-sounding and the highly pleasant ones seemed to be rated not so urgent," he said.
Nicastro suggests that cats may have developed different kinds of calls to "hook into human perception tendencies" and alert us of their mood and needs. He points out the animals have certainly had time to adjust for people.
Ancient Feline Friends
Records from ancient Egypt suggest that bonds between cats and people date at least as far back as 5,500 years ago when Egyptians began domesticating wild cats. The animals quickly became treasured pets and were honored in artwork for their snake- and mice-hunting skills. By 1500 B.C., Egyptians began regarding cats as sacred and it became a crime, punishable by death, to kill one.
Today, about 90 million cats are kept as house pets in the United States alone.
Nicastro points out that since cats have shorter life spans than people, they've had many more generations to evolve ways of manipulating their owners through their calls.
The suggestion of a co-evolution between people and domesticated animals is not new.
Other studies have found that dogs are highly skilled at following the gaze of people (possibly to spot food). And a horse known as Clever Hans demonstrated in the early 1900s how horses can be keenly sensitive to the body language of their masters. The horse's owner convinced people that Clever Hans was psychic when it correctly answered questions by tapping out coded answers with its hoof. Later studies revealed the horse was responding to subtle twitches and changes in posture of its owner.
While researchers say it's possible that cats may have evolved in a similar way to better communicate with people, they caution it's easy to jump to conclusions.
"It's conceivable they developed ways to communicate with people since they've interacted with people for so many years," says Douglas Nelson, a professor of bioacoustics at Ohio State University. "But the cats could also have evolved different calls to communicate with each other."
Screeching Ancestors
To zero in on possible human influence on the domestic cat, Nicastro went to a zoo in Pretoria, South Africa, and recorded the calls of wild desert cats (the animals thought to be the ancestors of domestic cats). He's still analyzing the sounds and plans to have people screen them, but his preliminary findings reveal very different vocalizations.
"They're much harsher and far less musical-sounding than domestic cats," Nicastro says. "When I've played the sounds for other people, they think they're leopards. They say they sound like cats on steroids."
Why bother studying something that probably a lot of cat owners might have already guessed? Because it's not really been done before, says Nicastro. He says the field of animal behavior and communication is rich with studies on rare and exotic species, but contains surprisingly little data on cats.
As he says, "We probably know more about obscure monkeys in Africa than we know about the animals hanging out in our own kitchens."
