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Alaska's North Slope
MAY 2006
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In Learn More the National Geographic magazine team shares some of its best sources and other information to expand your knowledge of our featured subjects. Special thanks to the Research Division.

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Did You Know?Did You Know?

Caribou are an important source of sustenance for the natives of Alaska's North Slope, where four main herds make up a total of around 690,000 caribou. If numbers were to dwindle, the food chain, local economy, and cultural practices would be greatly affected, so biologists keep close track of the herds by using radio or satellite collars and aerial photography.

In the north, satellite collars are typically used because their signal can be picked up even in the dark and during snowstorms. Within each lightweight collar is a transmitter that emits a signal to a passing satellite once a week for eight hours at a time—with enough battery power to last about 18 months. The satellite calculates the location of the caribou and sends the information on to scientists at one of three ground stations found in Alaska, Virginia, and France.

Attaching the collars is no easy task. In a river capture, biologists take a small boat out to a point where caribou are swimming across. They pick out one, sneak up behind it, and lasso its antlers. Once captured, the caribou is led closer to shore, so it will feel safe, and there the collar is put around its neck. This process, which takes only a couple of minutes, causes less stress than another common method in which a net is shot over the caribou from a helicopter, and the animal is tied up while it is being collared.

Once biologists locate the group of caribou with the largest percentage of collared animals, they venture out in small airplanes and photograph them using an aerial camera. Then other collared caribou not in the main group are found and photographed. In a time-consuming process, the photos are carefully laid out and each caribou is counted one by one. Scientists then analyze all the data to determine whether populations are decreasing or increasing.

Many people fear oil exploration and development on the North Slope will disturb local herds, particularly the Porcupine herd—named after the Porcupine River—which calves on lands in the 1002 Area of the Arctic National Wildlife Refuge. Scientists aren't sure if activities related to the oil industry have affected the herds in other areas of the slope, but they have observed that there is a tendency for calving females to avoid oil drilling areas. Other effects are still to be discovered, in part by these monitoring efforts.

—Emily MacDowell

Related Links

Arctic National Wildlife Refuge
Read about the landscape, animals, and native culture of the refuge. Then find research projects for students and teachers.

Audubon Alaska
A special report reveals the importance of the western Arctic coast's wetlands to uncounted millions of birds that migrate there from around the globe.

BP in Alaska
Understand BP's history in Alaska and stay informed about the latest technological advances in exploration and drilling via this corporate website.

This nonprofit environmental law firm is challenging the U.S. Department of Interior's decisions regarding opening sections of the National Petroleum Reserve (NPRA), most recently the Teshekpuk Lake area, to commercial leasing for oil and gas exploration.

First Whaling Trip
Children from the Nuiqsut Trapper School wrote and illustrated a book about two young Inupiat cousins who go on their first whaling trip. The book can be downloaded from the website of the North Slope Borough's ECHO Grant Project, an educational initiative that fosters students' interest in local history and culture.

Legacy Wells Project
Learn about the Bureau of Land Management's ongoing effort to plug problem wells drilled by the U.S. Navy, U.S. Air Force, and U.S. Geological Survey over a 40-year period in the search of oil in the NPRA.

National Petroleum Reserve-Alaska
To review the process of commercial development of NPRA lands, you can access public comments on recent environmental impact statements, as well as the final records of decision and maps of the tracts leased within this 23-million-acre (9.3-million-hectare) block of federal land.

North Slope Borough
October 2005 comprehensive plan of the borough's planning department presents an exhaustive survey of every aspect of life in the northernmost communities in the U.S.

Northern Alaska Environmental Center
This grassroots organization advocates for conservation and sustainable development in Alaska, and provides a wealth of educational materials on its website.

Wilderness Society—Alaska: Ours to Save, Ours to Lose
A rich and diverse collection of news, scientific reports, maps, and photos related to the natural wonders of Alaska's Arctic region is available on this site. You will also find up-to-date information about oil exploration and development on the North Slope as well as the politics of wilderness preservation.



Canby, Peter. "The Specter Haunting Alaska." New York Review of Books (November 17, 2005). Available online at www.nybooks.com/articles/18453.

National Research Council. Cumulative Effects of Alaska North Slope Oil and Gas. National Academies Press, 2003.

Strohmeyer, John. Extreme Conditions: Big Oil and the Transformation of Alaska. Simon and Schuster, 1993.

Truett, Joe C., and Stephen R. Johnson, eds. The Natural History of an Arctic Oil Field: Development and the Biota. Academic Press, 2000.

Waterman, Jonathan. Where Mountains Are Nameless. W. W. Norton, 2005.

Welch, Craig. "Ecological Jewel on the Brink of Change." Seattle Times, January 1, 2006. Available online at seattletimes.nwsource.com.

Welch, Craig. "Oil Drilling Alters Landscape, Life for Tiny Inupiat Village." Seattle Times, January 1 and 2, 2006. Available online at seattletimes.nwsource.com.

NGS Resources

Bourne, Joel K., Jr. "Alaska's Wildlife Archipelago." National Geographic (August 2003), 72-95.

Balog, James. "Expedition to ANWR." National Geographic Adventure (November/December 2001), 70-8, 80, 154.

Mitchell, John G. "In Focus: Arctic National Wildlife Refuge: Oil Field or Sanctuary?" National Geographic (August 2001), 46-55.
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