Ice Stories
Exploratorium Home

On the Edge of the Arctic National Wildlife Refuge

KAKTOVIK, ALASKA– Over last weekend the whirlwind pace continued. On Friday afternoon I threw my cold-weather gear into a bag and caught a small commercial flight to Kaktovik, about 120 miles east of Deadhorse. Kaktovik is a very remote town of about 300 people, including many folks of the Iñupiat culture. The town sits on the coast of the Arctic Ocean at the northern edge of the Arctic National Wildlife Refuge, or ANWR. Kaktovik is very different than Deadhorse – it has the character of a small town, rather than an oil extraction base. It is quiet, with two general stores and close-set houses separated by deep snowdrifts.

The United States Geological Survey (USGS) has been capturing polar bears in late winter in northern Alaska for decades, and their research provides much of the current science regarding polar bears. The USGS crew that performs captures often stages out of different towns in the Arctic, including Kaktovik, to access different regions.

The city of Kaktovik, Alaska, from the air. The airstrip is in the foreground. There are no roads to Kaktovik – you must fly in, travel by ocean, or make a long journey by land through the Arctic Wildlife Refuge.

On Friday, a USGS scientist picked me up at the airstrip when I landed in Kaktovik. We returned to the bunkhouse where the crew was staying and I jumped in to help to prepare platters of cheese and sausage, a pot of chili, and lots of coffee. We brought the food down to the community center and participated in a community meeting. A scientist from USGS and me had the opportunity to meet residents and discuss research activities based in their town, activities which involve an animal many folks there know intimately – the polar bear.

The USGS crew had already been capturing polar bears for several weeks. The next morning the temperature was -20 degrees (Fahrenheit) with light wind, and I went out with them. We had 4 people – a pilot and 3 researchers – in the helicopter. We departed Kaktovik and flew north over the ocean. We saw a lot of tracks but no polar bears until the afternoon. The USGS scientist used a dart gun to inject the polar bear with a drug that immobilizes the animal and puts them under anesthesia. Once the animal was down, we landed, unloaded our gear, and gathered samples from the bear – we weighed it, measured its length, girth, and skull size, and took samples such as fur and blood for later analyses.

One of the polar bears that we captured for sampling on Saturday, on sea ice several dozen miles north of Kaktovik. This is an adult male bear which weighed about 750 lbs.

A front paw of the same adult male. The size of polar bears always amazes me. This bear had paws that were as wide as my hand is long, and it was not even a large male. The largest males can weigh over 1500 lbs, twice as much as this bear. Their claws are shorter and much sharper than a brown bear (also called grizzly bear) – polar bear claws are better for walking on slippery ice and grabbing seals. The long claws of a grizzly are better for different tasks, such as digging up roots for eating.

Tags: , , ,

3 Responses »

  1. So- does the USGS capture more than once a year? Or just spring? And if a grizzly and a polar happen to cross paths, do they just ignore each other? Do grizzlies ever venture out on the ice?

  2. Hi,

    Most agencies, including USGS, generally only capture bears March-May. During this time many bears can be found on sea ice fairly close to shore, and the sea ice is thick enough to provide a good platform for helicopters to land on. In past years USGS has done some autumn capture work, but they found low capture rates and did not continue the work.

    However, as part of the 2008 USGS collaboration with the University of Wyoming for this project, captures occurred on shore during August. This provided very interesting data because little is known about bears during the summer. These bears were recaptured in October, also providing new data.

    Grizzlies, or brown bears, on the north slope are generally smaller than bears from southern Alaska. This may be due to the scarcity of food items on the tundra. Even so, it has been observed that when a brown bear approaches a polar bear feeding at a whale carcass on the beach, the brown bear often pushes off the polar bear.

    Personally, I wonder if this is because polar bears have not evolved the tendency to be territorial. Polar bears generally hunt seals at cracks and breathing holes in the ice, at constantly shifting locations in drifting ice; a polar bear would gain little by fiercely defending a given area of sea ice because the cracks and breathing holes may disappear tomorrow. Thus polar bears may not have evolved the tendency to be defensive against intruders - including brown bears.

    I do not know if grizzlies often travel onto the sea ice. Some of the USGS folks did relate an interesting observation. They saw a set of caribou tracks headed out onto the sea ice, which was very unusual - and they were followed by a set of wolverine tracks!

  3. Hey great article., I love to see people doing what they can to protect the animals.I know quite a bit about grizzlys but polar bears are quite foreign to me. I live in British Columbia so Ive run into a grizzly or two :D I do my best to study them from a distance. Such amazing animals!

    If your interested check out my article on staying safe from bear attacks!

    Bobby Southworth
    Bear Mace Preventing a Grizzly Attack