May 11, 2011

When Black Bears Attack, Don't Blame Maternal Instinct

The black bears most dangerous to people are not mothers with cubs but single bears—often males—prowling for food, a new study says.
The study also found, contrary to popular perception, that the black bears most likely to kill are not mothers protecting cubs. Most attacks, 88 percent, involved a bear on the prowl, likely hunting for food. And most of those predators, 92 percent, were male. 
This article in the New York Times includes a valuable video by bear-attack researcher Stephen Herrero, who talks about patterns in bear attacks.

I used to believe the "mother bear defending her cubs" idea too. Then, in the early 1990s, M. and I worked as contractors each summer for the Bureau of Land Management, counting Mexican spotted owls (and other owl species) in southern Colorado.

Since our work involved hiking from late afternoon into darkness, we had a number of encounters with black bears.

The first time we encountered a sow with two cubs in a narrow canyon, we immediately retreated. The we climbed up on a nearby rocky outcropping. We could hear the bears flipping rocks in the little creek, looking for food, and grunting at each other. Eventually, it became dark, and they had to be still out there somewhere. But we could not afford to wait all night, so we flicked on our headlamps and hiked out with many an anxious glance backwards. Never saw the bears.

Another time, another deep canyon, we met a mother and cub. Mom sent the cub up a tree, while the last we saw of her was her butt going over the ridge. We continued higher up the canyon to our calling spot. Meanwhile, the cub started to wail—a sound somewhere between the crying of a 100-pound baby and the bray of a donkey.

After trying unsuccessfully to find another way down that did not involve passing the cub, we eventually started back the way that we had come. By then Mom had come back, and they were both gone.

All other bear encounters were inconsequential. Most bears are shy.

Prof. Herrero points out that bears are still mostly "benign," when you consider that there are on average two attacks a year from a North American bear population of 750,000-800,000.


Darrell said...

What's the skinny on the guy killed by a bear north of Cotopaxi some years ago?

Chas S. Clifton said...

You're thinking of the Colin McClelland case in 1993. The bear did break into his trailer and kill him. I seem to recall some victim-blaming at the time to the effect that McClelland had left food outside and that the bear had become accustomed to finding food there.

Hal Walter discussed the case in this article.

Darrell said...

Thanks, Chas, very interesting article. One statement got me:
"McClelland, who says he once had a black bear lick insect repellent from his face in Yosemite"--on some Discovery or such program about a bear-lovin' guy, he remarked that bears LOVE citronella. They showed video of him wearing citronella while sitting under a tree, a bear came up to him, and started acting like a cat with catnip. The bear was all over the man, not attacking him, but LOVIN' that citronella! LOL

Tam said...

Black bears are pretty shy, too. Predation attacks almost always come from bears that are half-starved.

Of course, as rebounding black bear populations in the east combine with increasing suburbanite sprawl in the foothills of the Appalachians, interaction between black bears and humans is on the increase, so we'll see how long they stay shy...