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Home > Programs and Policy > Habitat Conservation > Federal Lands > National Wildlife Refuges > Threats > Arctic National Wildlife Refuge > Wildlife Impacts

Polar Bears in the Arctic National Wildlife Refuge

Polar bearA symbol of the wild Arctic and an integral link in its complex food chain, proposals to drill for oil in the Arctic Refuge would have a huge impact on America's polar bear population. The coastal plain of the Arctic Refuge is the nation's most important onshore polar bear denning habitat. Pregnant females come ashore in November and December, build an ice den and give birth to one or two cubs. About 40% of the dens used by the Beaufort Sea population in Alaska are onshore and more than 60% of these are on the Arctic Coastal Plain.

Individual polar bear dens are extremely difficult to locate and therefore also difficult to avoid disturbing. Protection of onshore denning habitat is crucial because polar bears have a low rate of reproduction and are especially sensitive to human disturbances like aircraft, ships, road construction and traffic, pipelines, seismic work, drilling and oil transport activities. Once disturbed, polar bears may abandon their dens, leaving their cubs to die. According to a 1987 report by the U.S. Fish and Wildlife Service, "early den abandonment can be fatal to cubs unable to fend for themselves or travel with their mother."

Oil spills can also be particularly catastrophic. The U.S. Fish and Wildlife Service (FWS) notes "Bears which have been fouled by oil may suffer thermo-regulatory problems, ingest oil, and may exhibit other detrimental effects such as inflammation of the nasal passages or central nervous system. Bears that contact oil are likely to die."

Because polar bears exist in relatively small populations and have low reproductive rates (only a quarter of the female bears become pregnant in any given year), they are highly susceptible to even small decreases in population numbers. Alaska's Beaufort Sea population of 1,800 polar bears appears to be stable currently, but even small decreases in bear cub survival or increases in female mortality could be devastating.

The myriad risks to polar bears from oil field development include:

  • Disturbance of females while denning could cause them to abandon cubs.
  • Death, injury or harassment resulting from encounters with humans.
  • Damage or destruction of essential habitat (e.g., feeding, breeding and especially denning areas) by dumping, dredging, drilling and construction of platforms, pipelines, roads and support facilities.
  • Contact with and ingestion of oil and other contaminants (e.g., ethylene glycol antifreeze, heavy metals, organochlorines, etc.) used in oil production.
  • Attraction to industrial areas with subsequent habituation to humans and increased control actions.
  • Harassment (disturbance) by aircraft, ships and other vehicles (stress/overheating when fleeing, interruption of feeding).
  • Detrimental effects on the polar bear's main source of food, ringed seals, due to impacts of oil, noise and other contaminants.
  • Increased hunting pressures due to greater access.

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