The red fox is a familiar creature here in Japan, but travel northward and it is soon replaced by another species. At higher latitudes, the arctic or polar fox is the ubiquitous hardy scavenger and predator. It is better adapted to the colder conditions, with a shorter muzzle, smaller ears and a thicker, denser coat than the red fox. It is about three quarters the size of a red fox, and unlike that animal, it has fur on the soles of its feet, which give it excellent insulation throughout the winter while foraging across snow- and ice-covered habitats.

These grayish-brown creatures do not hibernate to escape the winter; instead they turn white, and rely on their camouflage to help them hunt, and on their specially insulating fur coat to help them weather the sub-zero temperatures.

Their natural range rings the Arctic, wherever there is tundra or tundralike habitat. Although most widespread in the northernmost parts of the North American and Eurasian continents, arctic foxes also occur naturally on a number of islands off the Alaskan and Russian coasts. Because of their luxurious fur, and because of past interests in fur harvesting, arctic foxes were introduced by fur farmers to a number of islands in the Aleutian and Kurile Islands.

Animals were simply turned out to fend for themselves, with the hunters returning some time later to harvest the population. In their natural range, they are predators on vole and lemming populations, on birds and their eggs and young, including seabirds, and, particularly in winter, they move to the coast where they scavenge for anything that might be edible.

Where they have been released for fur farming, they have played havoc with populations that previously had no such predators. As alien predators, they have contributed to serious declines of a number of species, most notably the Aleutian Canada geese.

During my travels around the Bering Sea this summer I encountered them on a number of offshore islands. It had long been my dream to see them on Bering Island, but unfortunately that dream was thwarted. A storm blowing westward across the Bering Sea brought strong onshore winds and high waves, which prevented me from going ashore on the southeastern coast of Bering Island.

It was a sad day for me, as I had long dreamed of walking where my hero, the naturalist Georg Wilhelm Steller, had wintered after being shipwrecked in 1741. The bleakness of the landscape, evident through the flying spray and the miserable weather, were reminders, however, of how awful it must have been to be forced to spend nine months in such a place over winter, and with none of the comforts of our modern lifestyle.

It is hard to envisage the extraordinary extent of the wildlife populations that Steller observed there on that remote island 250 years ago. Several of the species that he studied there are now extinct, including the enormous sea cow that was named after him. Neither the fur seals nor the sea otters occur in even a fraction of the numbers that they once did, and the arctic foxes have certainly declined.

The ill-fated crew members of Bering's ship, the St. Peter, were forced to overwinter in the roughest of conditions on the Commander Islands, between the Aleutians and Kamchatka. Finding sufficient food was a serious task and whatever food they secured was constantly at risk of being stolen by scavengers.

In those days, arctic foxes were so common on the island, and so unconcerned by unfamiliar humans, that they scavenged anything and everything, edible or not, and were a constant nuisance. They mutilated the dead and dying sailors, and even bit at the living. However well food was buried or protected, the ubiquitous foxes found it. The shipwrecked sailors were forced to sleep with clubs in their hands to defend themselves if woken by foxes, and on one occasion, Steller killed over 70 of them in three hours.

If Steller was able to kill so many in such a short time, the population along the island's coast that winter must have been phenomenal. It is hard to imagine how many were drawn there to scavenge from the waste of the various marine mammal colonies. Now, if one encounters more than a handful of arctic foxes in a day it is a red-letter day, yet some of them retain their fearlessness.

As I waded ashore on one of the central Kurile Islands, I noticed two arctic foxes playing together, chasing each other back and forth along the beach. I expected them to flee immediately, but even as I walked up the black volcanic sand, they were unconcerned and continued their game. Perhaps they were well-grown young from the same litter, or perhaps they were just two young adults that were pleased to see each other.

One of them broke off from the game, and continued along the beach, foraging along the line of tide-washed seaweed. The second set off in the opposite direction but came back to investigate me and to see if I would play too. Once it realized that all I did was click and whir when it came close, it soon tired of me too and went off along the beach ahead of me.

The flanks of the island volcano were lost in low cloud but every few minutes strange yelps and shrieks reached my ears through the fog. It was a while before I realized that these were the calls of the foxes shrieking at one another. The two I had seen were merely the greeting party on the beach; there must have been dozens on the island.

This particular island consisted of a volcanic caldera, breached on one side and filled with sea water.

As I wandered along the rocky beach which formed the inner crescent of the island, I was surprised to see a long, dark shape in the water, where I expected to see only seabirds. Through my binoculars I found myself watching another of the islands many foxes dog-paddling its way across the flooded crater. It was in no hurry to land and for a while it swam along just off the rocks along the far shore, before eventually climbing out and disappearing into the dense summer grass.

Later still, I found another of them curled in a tight ring between some rocks. I could have reached out and touched it, so unconcerned was it by my presence. As I sat next to it on the rocky beach, it was easy for me to imagine how a horde of these mischievous, playful creatures would play havoc around a camp and my sympathy for Steller and the crew of the St. Peter increased further. It was also easy to imagine what an impact so many predators could have.

In the western Aleutian Islands, the Aleutian Goose, a small sub-species of the Canada goose, was so rare in 1972 that it was listed under the then new U.S. Endangered Species Act. From a low of 400 birds, the population has surged to as many as 30,000 today.

The reason? The arctic foxes that had been introduced to those islands by fur trappers and which had caused havoc among bird populations, were recently systematically eliminated from the islands in a conservation management program. With the alien nest predators gone, the geese were able to recover, confirming that the introduction of alien predators such as arctic foxes is a serious issue on many islands.

If you have questions or comments, you can reach me via e-mail ([email protected]) via snail mail care of The Japan Times.