What’s on the menu, grizzly bear?

July8
July8

July 08 2015, 9pm in Alaska, tune in to KAKM Science Wednesdays, Alaska Public Media, for FrontierScientists’ GRIZZLIES.

Wildlife biologists and Park rangers in Denali National Park & Preserve help the Park’s grizzly bear population thrive in their natural environment while promoting safe interactions between Grizzlies and visitors. Catch clips online at http://frontierscientists.com/projects/denali-bears-grizzlies/.

GRIZZLIES: AIRED on KAKM’s Science Wednesdays in Alaska at 9pm, after Nature & NOVA.

Denali National Park & Preserve wildlife biologist Patricia Owen tells the story of finding the biggest bear she’s ever caught in this FrontierScientists video clip: Pat’s Big Bear.

While bears south of the Alaska Range have access to more fish and often reach a weight of 800 pounds, Owen was surprised to find an 800 pound bear north of the Alaska Range where she says pickings are slim.

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On the menu

Bears are omnivores. They “Basically eat whatever is edible that they happen to come upon,” Owen said. “They are meat eaters at certain times of the year more than others.” “They focus on caribou and moose calves in May,” but “Don’t spend a lot of time trying to take down adult ungulates.” Bears may lay claim to the carcass of an animal that wolves killed, but “Generally bears in interior Alaska eat a lot of vegetation. They are eating early green shoots in the spring; they are digging up roots and tubers.” When berries ripen “They are heavily into eating blueberries, soap berries, whatever kind of berries they can find,” including crow berries. Owen explained that “Most of the year they are not eating meat, they are eating vegetation. And that doesn’t provide the sustenance that a protein meal does. So it is a little tougher life here than other places.”

You don’t want to bother a bear that has found meat. Park rangers post signs, keeping kill sites “Off limits for human safety as well as to minimize disturbance.” A bear will eat from a carcass, then use their powerful digging claws to cover it up before taking a nap right on top of it. “They’ll sleep for a couple of hours,” Owen explained, “Get up, uncover it a little bit, get a meal out of it, cover it up again and camp on top of it until it’s gone.”

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Nibbling

As a wildlife biologist Owen knows all the tricks to understanding a bear’s diet. “It’s really interesting to watch them because you can tell from some distance usually what it is that they’re eating because of the way they go about it.” The motion of a nibbling bear’s head is a dead giveaway when it comes to soapberry bushes: “The bushes are low to the ground and the berries are on the undersides of the bushes and the bears actually use their paws quite a bit to manipulate the branches,” bending the branches so they can “Nibble with their lips and their teeth and pull those berries off while they’re turning the branches over with their paws.”

While eating soapberries call for armfuls of branches and nibbling, eating low-growing blueberries calls for head motions moving up and down.

You probably don’t want to sample all the berries. Owen: “There’s a reason why they call them soapberries: because they taste like soap. They’re really not very pleasant but they are very high in sugars and they help the bears put on some fat for the winter.”

Scat

Hiking in Denali, you’ll probably come upon evidence that a bear passed by: bear poop, called scat. Get a little scientific and find out what the bear was eating by examining the scat.

“Get a good close-up of that one!” Owen told the cameraman. She said “It’s an old scat that’s mostly grasses,” “If you look closely you can see a lot of the grasses,” pointing out the vegetation still discernible inside. It’s a common sight for “An earlier spring scat, where they’re eating lots of new vegetation.”

“It’s dark; that’s pretty typical. Meat scats are almost black. Berry scats,” though, “look like hardly-processed piles of berries.” And now you can tell what Denali bear residents have been chowing down on.

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Denali population

In a push to learn more about bear population numbers park researchers “Collared as many bears as we could find” in the mid-nineties. Counting the number of bears in the study area allowed for “Appropriate density estimates,” using those numbers to “Extrapolate to other areas of the Park where we know we’re going to find bears.”

Owen said “We came up with a number of 27 bears per thousand square kilometers, which doesn’t mean a whole lot to most people. But if you take that number and extrapolate to all the places in the Park boundary where we would expect to find bears based on habitat that number comes out to be somewhere between 300 and 350.” So it’s likely that in all Denali National Park and Preserve land that’s north of the Alaska Range, there are at most 350 grizzly bears.

Interior Alaska has low prey availability, so bear population densities there are lower than in other parts of the state where densities can go “Probably from 25 bears per thousand square kilometers up to a couple hundred bears in some places.” Owen, scientists and park rangers work to protect and manage that population of Denali grizzlies.

Natural systems

It’s important to Owen that bears and humans interact in Denali in a way that’s safe and respectful to both species. “I know the reality of the world that we live in today, and I know that the reality is not everything is ever going to be the way it used to be but I think it is really important for us to be able to have places where things function as part of a natural system and bears are just one piece of the natural system.”

“I’ve learned so much about bears, it amazes me everyday,” Owen said. “They are incredibly adaptable. I think we can learn a lot from grizzly bears especially.”

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Watch more science

At FrontierScientists, new scientific discoveries in the Far North unfold before your eyes. A fascinating series of video programs brings Arctic science to life, following real scientists and their work. This is field science in one of the last great frontiers.

After watching a FrontierScientists program on KAKM, navigate to www.FrontierScientists.com to explore research topics in more detail and pose questions directly to featured scientists. “We want to let travelers, teachers, students, aspiring scientists, and anyone else interested in science feel as if they are with scientists as they track grizzlies or take the temperature of permafrost in a borehole,” explains Liz O’Connell, FrontierScientists Director.

Laura Nielsen 2015

Frontier Scientists: presenting scientific discovery in the Arctic and beyond