ANNE McILROY

Friday, February 9, 2001

Moose may be friendly, but they aren't dummies.

A paper published today in the journal Science reports on how moose populations that have lived without predators for 50 to 130 years fared when well-meaning conservationists reintroduced grizzly bears and wolves into their territory.

When they began their work, the American and Norwegian scientists said the worst-case scenario would be a small-scale repeat of the mass extinctions that took place after humans began hunting the large mammals of North America 10,000 to 50,000 years ago.

University of Nevada researcher Joel Berger and his colleagues wondered if the naive moose would go the way of the giant beavers, short-faced skunks, saber-toothed cats, mammoths, mastodons and North American horses. It is not clear if predators alone caused the mass extinction, or whether climate change was also a factor. The researchers hoped the fate of the moose would shed light on how so many large mammals disappeared forever from the North American landscape.

At first, the moose were a little too friendly to the newcomers, and paid for it with their lives.

"They were highly vulnerable in initial encounters," the scientists said.

They compared the behaviour of moose in Sweden, Norway and Wyoming, where they have had life pretty easy, to moose in Alaska, where bears and wolves are a common threat.

The naive moose were getting slaughtered at a much higher rate, and the scientists could see why.

The Alaskan moose took off the instant they caught a whiff of grizzly or wolf urine. The naive moose ignored the same smell, or in some cases appeared fascinated by the new odour and would approach to investigate.

The howl of a wolf is like a fire alarm for an experienced moose. They get ready to run or fight, dropping their heads, retracting their ears and raising the fur on their necks. For the naive moose, it was background dinner music. They kept right on feeding. Raven calls are another sign of trouble for a moose that is used to watching his back, but naive moose didn't realize the scavenger birds were waiting for blood.

The scientists found the naive moose were "conspicuously lacking in astuteness," and experienced a "blitzkrieg," a form of offensive warfare developed by the Germans in the Second World War that involved large-scale attacks by mechanized troops and tanks supported by dive-bombers.

But moose mothers saved the day. Once they had lost calves killed by unfriendly newcomers, they wised up and concluded that grizzlies and wolves were indeed predators.

They became far more vigilant, dramatically changing behaviour to protect their young. Howling wolves became a signal to get moving. Their calves learned to fear grizzlies and wolves.

"What is evident is that naive prey have the capacity to process information about predators swiftly -- in the case of these moose, in a single generation."