A little bear on bear action

A little bear on bear action never hurt anyone… well, except for the smaller bear.

I’m finally back at work full time after my medical leave and it actually feels pretty good. I’m buried into GIS analysis right now and while I’m looking at the bear GPS points, there’s some bears doing some pretty interesting things live on the ground.

Bear on Bear – a part of nature

This week, the media has been all a buzz with the discovery of a grizzly bear feeding on the carcass of another grizzly bear. Does this happen a lot? Are bears really eating each other all the time? The story is covered in the Calgary Herald and the Rocky Mountain Outlook and paints an interesting picture.

A week ago, a friend of mine and her colleague went out into the woods to retrieve a grizzly bear’s collar that had fallen off. The collar belonged to 136, or split-lip as he is nicknamed, one of the dominant male grizzlies in Banff National Park. They found the collar and they also found the body of another grizzly bear that had been eaten and was surrounded by grizzly tracks. Due to some specific characteristics in the skull, Parks Canada concluded the grizzly carcass belonged to 132, a small male.

It is not possible to conclude that 136 killed 132, but it definitely looks like he was eating him. In the bear world, this is not a big deal. Bears eat meat and they aren’t picky about where it comes from. They don’t care if it’s another bear, if there’s meat to be eaten then bears will eat it.

It reminded me of this picture that a friend posted on my facebook last month:

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We like to think that bears won’t eat other bears but bears aren’t people. People don’t eat people (usually). Bears aren’t as picky.

The Bear Truth

Bears have 7 months to satisfy all of their nutritional requirements for 12 months of the year. Not only are they trying to eat all the time, but they are always trying to eat the thing that has the most calories and protein. Nothing beats meat. In the fall, before hibernation, bears are in hyper-drive eating mode. It’s their last chance to put on fat before sleeping for 5 months. So if a bear is walking through the forest and there’s a dead animal to eat, he’ll eat it. It doesn’t matter if it’s an elk, sheep, or another bear. More meat equals more fat equals a higher chance of survival during and post hibernation. It’s that simple.

While we don’t know if 136 killed 132, that wouldn’t be that odd either. Dominant male bears, like 136, become dominant for a reason – they are bad ass bears who run around letting every other bear know that. Dominant bears engage less dominant bears in fights over females or food or something else, and sometimes one of the bears loses and dies. Dominant male grizzlies have also been known to kill female grizzlies, particularly those with cubs, to bring the female into estrous so she can be mated by the dominant male.

While we (and I definitely include myself in this) like to think of bears as cute and smart and sometimes gentle and patient, they are also carnivores with big teeth and claws and sometimes they use them. It’s the reason why you should never be complacent in bear country, ever.

Check out these two male bears in Alaska having a little disagreement. It’s intense – fur is flying and it’s pretty full on. It’s easy to see how it can get dangerous for one of the bears.

What does the data say?

Ironically, while all this has been happening, I’ve been looking at the GPS data and the home ranges of the Banff bears. There is information in there that helps shed some light on how these dominant males use the landscape and how that’s different from smaller bears. A bear’s home range, the space it roams to get all the resources it needs to survive (food, mates etc.), changes throughout the season. The home ranges for dominant males are much larger than other bears to, as one of my colleagues said, “chase all those ladies around and get as much food as possible to do so.” The home ranges for bears 132 and 136 in the fall are around 400km2 in size, and overlap with several other bears, including each other. This means these bears are running into and interacting with each other and other bears more often than female or subadult bears (whose home ranges are around 150km2). (To put this all into a bit of an interesting perspective, Bear 122, the Park’s most dominant bear has a home range over 1000km2 in the fall – he is everywhere and probably knows everyone…)

Habitat quality in the Canadian Rockies is not very high, which means that bears who live here are constantly seeking food. With their bellies usually only half full, our bears have a lower tolerance for disturbance from people or other bears. Our bears, therefore, are more likely to be defensive over resources than coastal bears who live in very high quality habitat and are always well fed. Basically, bears in the Canadian Rockies like their space to roam around and get what they need when they need it.

So it’s not too unusual for bear 136 to eat bear 132, or even kill bear 132, especially if he was defending some kind of resource or territory. Is it crazy to imagine? Sure. But we think it’s crazy because we’re people – bears don’t think it’s crazy at all, they think it’s a bear’s life in search of food in the Canadian Rockies.

Bear 132 in a trap earlier this spring. I was sad to learn he met such a fate, but he was a small adult male. Little cutie.

Bear 132 in a trap earlier this spring. I was sad to learn he met such a fate, but he was a small adult male. Little cutie.

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