By Matt Wasielewski
“A dog can’t tell you, ‘Hey I smell marijuana’ or ‘I smell meth,’ ” a police chief said. Drug training for a police dog. (Ryan David Brown for The New York Times)
Sure, your dog can fetch, or roll over or bring you your slippers. He may even be considered part of the family.
But your dog is not special.
According to a recent study, dogs are no more intelligent than the rest of the animal kingdom.
“Almost everything a dog claimed to do, other animals could do too,” Stephen Lea, the study’s co-author, told The Times.
Dr. Lea and his colleague compared studies of dog cognition with those of wolves, cats, chimpanzees, dolphins, horses and homing pigeons, among others. What they found, Dr. Lea said, was that “dog cognition does not look exceptional.”
“Far be it for me to suggest that pigeons are smarter than dogs; they are not intellectual giants,” Dr. Lea said. “But if you want to get 1,000 miles, I trust a pigeon over a dog.”
He suggests that the fact that dogs can be trained to carry out certain tasks is why humans believe they are smarter. But that training has its limits, as police forces in North America are finding out.
Across Canada and in some American states, drug-sniffing dogs are being forced into early retirement by the legalization of marijuana.
“A dog can’t tell you, ‘Hey, I smell marijuana’ or ‘I smell meth,’ ” Tommy Klein, the police chief of Rifle, Colorado, told The Times. “They have the same behavior for any drug that they’ve been trained on.”
A Colorado court ruled that a dog trained to smell a variety of drugs could not be trusted to detect illegal activity during a traffic stop because it could be alerting police to a now-legal drug.
Part of the problem, experts say, is that dogs really do have trouble learning new tricks, which makes it difficult to teach them to stop picking up on scents they were trained to hunt for.
But their keen sense of smell — their noses are 10,000 to 100,000 times as sensitive as human noses — can be put to use in other environments.
Dogs are able to detect bladder and ovarian cancer in urine samples and lung cancer in breath samples. Another study has shown that they may also be able to sniff out malaria, The Times reported.
The research revealed that dogs can accurately identify socks worn overnight by Gambian children infected with malaria parasites. The researchers are not sure what the dogs are smelling, but the parasites produce organic compounds similar to those found in perfumes.
If just one chemical indicated malaria, “we’d have discovered it by now,” said Claire Guest, who oversaw dog training in the study. “It’s more like a tune of many notes, and the dogs can pick it up.”
Inexpensive rapid tests for malaria are already available. But dogs could be used to sort through crowds of people in countries that have eliminated the disease but share borders with countries that have not. The dogs could also be used to sweep villages in regions that are close to eliminating the disease to ferret out carriers, The Times reported.
But even these canines, which could potentially save a life, are not so special. Steve W. Lindsay, one of the malaria study’s authors, told The Times that it would be possible to train local animals, like African giant pouched rats, which have been used to detect land mines and tuberculosis, to do the same work.
“But at ports of entry,” Dr. Lindsay said, “I think people would rather see dogs running around than rats.”