If you could talk to the animals, would they have anything to say? New research suggests they might.
Testing the IQ of a sheep may seem laughable. But at the Babraham Institute in Cambridge, England, they know better. One sheep who got a reward every time she recognized a human face correctly on a video screen scored a perfect 50 out of 50.
"If it was a monkey, no one would have any problems, possibly even if it was a dog," said Keith Kendrick, a neurologist at Babraham. "They would say, 'Yeah, yeah, that's expected.' But a sheep, no one really believes."
And it's not just sheep.
Hamlet the pig is a computer wiz. He gets a reward every time he uses a joystick designed for a chimp to move a cursor into a blue area on a computer monitor. A Jack Russell terrier couldn't achieve such a task after a year of trying.
In other words, pigs are smarter than dogs.
"They're very curious, and they'll charge off on their own," said John Webster, a professor at the University of Bristol in England. "They will investigate the world with their noses down and batter through like a small boy."
New research shows that chickens can be taught to run the thermostat of the chicken coop, and that even the lowly cow has a surprising inner life.
Cows have been known to form lifelong friendships, and one recent study found that they actually show excitement when they've learned something new "as if they're saying, 'Eureka, I found out how to solve the problem,' " said Donald Broom, a professor at the University of Cambridge.
If farm animals are intelligent creatures, should we all be vegetarians?
"We should eat less meat," said Jane Goodall, who pioneered research on chimpanzees.
Goodall is a vegetarian.
"I stopped eating meat as soon as I began to really think about it," she said. "People actually don't think about it."
John Redmore, who runs an organic farm in England, disagrees.
"We've been eating meat since we've managed to stand on hind legs," he said. "A natural part of being human is to eat meat."
It's natural to eat animals even if they're smart, he added.
"Yeah, they'd eat us," Redmore said.
But, he added, farm animals should be treated with compassion. After all, the research shows they may be able to recognize it.
ABC News' David Wright originally reported this story May 14, 2005, on "World News Tonight."