Raccoons are ubiquitous throughout much of North America, easily recognized by their distinctive black masks and ringed tails. They thrive in a variety of habitats from forests to cities, where they den in hollow trees, abandoned burrows, brush piles, and even chimneys. Raccoons are highly adaptable generalist omnivores that eat everything from insects, rodents and eggs to fruits, nuts and garbage. So why have they failed to colonize the vast wilderness of Alaska?
The History of Raccoons in North America
During the last ice age, raccoons were restricted to small portions of Central America and the southeastern United States that remained warm and forested. As the glaciers receded around 10,000 years ago, raccoons began expanding their range northward and eastward across what is now the continental United States and southern Canada. By the time Europeans arrived in the 1600s, raccoons occupied nearly all of their current distribution except for the far northern areas of North America.
In the 1930s and 1940s, Soviet authorities deliberately introduced raccoons into western Russia for fur farming. Some escaped or were released, and raccoons quickly colonized eastern Europe and parts of the Caucasus Mountains. More recently, raccoons were introduced to Japan where populations have become problematic invasive pests on the island of Hokkaido.
Despite over 400 years of opportunity, raccoons have never been able to extend their range across the treeless tundra into Alaska. Only one wild population is known to exist in the state, on a remote island near the southern tip of the Alaska Panhandle.
The Challenge of Dispersing Across the Boreal North
So what prevents raccoons from spreading north into Alaska? Raccoons face several challenges dispersing across boreal and arctic regions:
- Harsh winters – Raccoons lack adaptations for surviving cold winters with temperatures below -22°F and continuous snow cover. Raccoons do not hibernate and build up limited fat reserves for winter.
- Scarcity of food – The long winters and short growing seasons of the far north limit availability of plant foods and insect prey.
- Isolation of populations – The vast expanses of treeless tundra provide few opportunities for raccoons to cross between forested areas. Raccoons have poor stamina for long distance travel across open areas.
These factors restrict raccoons to areas with relatively mild winters in the contiguous United States and just barely into the boreal forests of southern Canada. However, Alaska’s remote location and harsh climate pose unique challenges.
Alaska’s Unfavorable Climate
Alaska has the harshest winter climate of any U.S. state, with average January low temperatures below 0°F across most of the state. The northern half of Alaska lies within the zone of continuous permafrost where the subsoil remains frozen year-round. These conditions impose severe energetic constraints on mammals trying to survive the winter.
While raccoons occasionally range into the boreal forests of Canada, the environmental conditions in Alaska are far more extreme. For example, Fairbanks in central Alaska has average January lows around -20°F compared to Edmonton, Alberta at just -7°F. This difference of over 10°F means shorter, colder winters in Alaska that raccoons are unlikely to withstand.
Average January Low Temperatures:
| City | Average January Low (°F) |
|---|---|
| Fairbanks, AK | -20 |
| Anchorage, AK | 11 |
| Juneau, AK | 21 |
| Edmonton, Alberta | -7 |
| Minneapolis, MN | 2 |
The climate also limits the availability of food during the critical winter months. While raccoons in more temperate climates can scavenge human refuse year-round, northern populations rely heavily on fruits, nuts and other natural foods to fatten up before winter. The far north simply lacks enough calories to sustain raccoons through the long months of deep cold.
Isolation Across the Arctic Tundra
The vast expanses of tundra separating islands of suitable habitat also impede raccoons from dispersing north into Alaska. Raccoons have limited endurance for long distance travel and actively avoid crossing large open areas away from forests, ponds or stream corridors.
Numerous rivers, mountains and glacier fields impose additional barriers across the Yukon between British Columbia and Alaska. These inhospitable arctic landscapes isolate mammal populations and prevent range expansion. With global warming, some southern species like red foxes and coyotes have gradually spread northward but raccoons appear limited by their weaker dispersal abilities.
Failed Introduction to Alaska
In the 1930s, several attempts were made to intentionally introduce raccoons in Alaska for fur farming. Twenty raccoons were released near Eskimo Point along the Kuskokwim River in western Alaska. The introduced raccoons perished within two years due to the harsh winters and lack of food. This failed translocation reinforces that Alaska falls outside of the viable range for raccoons.
A single population has managed to gain a tenuous foothold in Alaska on Revillagigedo Island near Ketchikan at the state’s southern edge. Their persistence in this marginal habitat suggests that raccoons may eventually expand their range northward in Alaska with climate change if winters become milder. But they are unlikely to spread far beyond southeast Alaska which has a relatively moderate coastal climate.
The Raccoon’s Northern Limit
The inability of raccoons to expand across the boreal zone and colonize Alaska is indicative of the geographic barriers to dispersal presented by North America’s far northern landscapes. While raccoons exhibit amazing adaptability in urban areas, they lack key traits required to inhabit the Arctic such as exceptional cold hardiness, stamina for long distance travel, and flexibility in diet. Their northern limit approximates the -22°F January isotherm which marks the extreme of temperatures raccoons can withstand.
Raccoons are restricted to areas with relatively mild winters and productive summer seasons to accumulate the fat and food needed to survive the winter and breed the following year. The harsh conditions of Alaska simply exclude raccoons from much of the state’s vast wilderness. So for the foreseeable future, this ubiquitous carnivore of southern Canada and the United States will remain absent from the Last Frontier.
Conclusion
In summary, raccoons are excluded from Alaska by the state’s extreme winter climate, isolation from source populations by vast expanses of tundra, and lack of food resources to sustain them year-round. Attempted introductions failed, proving Alaska falls outside the viable range for raccoons. One marginal population on Revillagigedo Island suggests limited opportunities for expansion in the state’s southeast panhandle. But beyond this region, Alaska will likely remain too harsh and inaccessible for the ubiquitous raccoon.