Bruins: Built to Sniff

Those of us who spend much time in the field with hunting dogs often find ourselves in awe of the canine olfactory prowess. But even the best tracking dog’s nose doesn’t come close to the sniffing ability of grizzly bears, says a former pioneering neurosurgeon who today specializes in bruin physiology.

Dr. George Stevenson, a retired neurosurgeon who now hails from Jackson Hole, Wyo. has been studying the brains of grizzly bears for the past several years, publishing papers and presenting seminars on the bruin’s incredible sense of smell.Griz

When it comes to sniffing things, bears are simply the best, Dr. Stevenson says.

“These bears are amazing creatures,” Stevenson told the Missoulian newspaper. “I believe they have the most impressive olfactory system of any animal on the planet. Their nose is the very best.”

Just how good is a bear’s sense of smell?

Considering that the average dog’s nose is 100 times more sensitive than a human’s, and the very best dog may have a sense of smell 300 times greater than man—a grizzly’s sniffer is at least 7 times more powerful than the best hound, according to Stevenson.

“It’s how they know the world,” he says.

In studying bear brains he has obtained from state wildlife agencies in recent years, Stevenson has found that the portion of a bear’s brain devoted to scent is at least five times greater than the percentage of the human brain allocated to olfactory systems.

Taking into account that a human brain weighs about 1,500 grams, compared to a 450-gram bear brain, the olfactory portion of the bruin’s brain is significant, says Stevenson.

“A polar bear will walk 100 miles in a straight line to reach a female ready to breed,” he said. “That’s what the bear’s nose can do. They smell a million times better than we do.”

Not only does that last tidbit attest to an incredible sense of smell, but I’d say it also speaks volumes about the male polar bear’s sexual drive, wouldn’t you?

Fascinating stuff, indeed.