Rural: Across the Arctic by dog

One of the less savoury moments of the journey came when the beavers started to go off. In north Quebec, wanting more nutritious food for her huskies, Wendy Smith took 40 frozen carcasses on board one of the expedition's trucks, and she was disconcerted to find that the animals were delivered skinned but with heads, tails and guts still in place. "The dogs loved them," she recalls. Too late, she realised it was a mistake to feed them the beavers whole: the huskies got diarrhoea, and the rest of the carcasses, rapidly becoming high, had to be thrown away.

Looking at Wendy, you would never guess that 10 years ago she almost died of cancer. At 36 her eyes are bright, her complexion is glowing, her movements are quick. The fact that she looks so fit is hardly surprising, for she has just pulled off a colossal feat of endurance - the first- ever dog-trek clean across the North American continent. During the winter she mushed (drove her husky teams) more than 4,000 miles, to show other sufferers that cancer can be beaten, and to raise funds for research.

A former Army officer, she was stricken by Hodgkin's disease in 1988, and became so ill that she and her family all thought she was going to die. But she fought back with astonishing courage, made a sudden recovery, and returned to energetic pursuits, leading treks in many wild parts of the world.

It was a fascination with wilderness, snow and huskies that led to her marathon mush across the Canadian Arctic. Having rounded up four supporters, she flew to Alaska last October to collect her dogs and equipment. Her team manager was Mark Howard, a policeman who for a year had given over his house in Oxford for use as an office. The member with most cold weather experience was Crispin Day, the polar explorer. Will Locke, a mountaineering pal of Mark's, joined because he had six months free, and Maggie Annat, an old friend of Wendy's, went along - as she thought - for the first couple of weeks, but ended up covering the entire distance.

In Anchorage the team spent two weeks assembling dogs, food, vehicles and other essentials. Then, in eight days, they hurtled across to Maine, on the north-east coast of America - an epic, 6,000-mile journey in itself. With three drivers sharing two hefty pick-up trucks, they were on the road for 16 hours a day. The 20 huskies travelled in a specially-built wooden box with separate compartments, 10 a side, each with its own door. Every four hours they had to be taken out and pegged, to stretch and relieve themselves (if ever let loose, they would run off or start fighting).

After two weeks' shaking down, the expedition set off on 15 November. Wendy's hope was that to be able to travel by sled, but as a back-up, in case she ran out of snow, she had an all-terrain vehicle (ATV), a Polaris quad bike, which the dog teams could pull instead. When 6in of snow fell the night before she left, it seemed a wonderful omen. Alas, it proved false: the whole way she was plagued by unseasonably mild weather, which she blamed on El Nino, and had to resort to the ATV for more than a third of the journey.

So began a phenomenal test of stamina. Every morning the team was up in the dark at 4am, getting the huskies out and feeding them - itself a two-hour task. Wendy would start mushing at 7am, and carry on for 12 or 14 hours, stopping only for her crew to change teams. She herself drove every yard of the way. With the sled she could warm up by occasionally jumping off and running or skating, but on the ATV she got so frozen that at the end of a stint her legs would not work, and she more or less toppled off.

Two of the team would generally be ranging ahead on snow machines, reconnoitring the trail, and if necessary breaking it. The trouble was that most of the trails that would have been open in a normal winter simply did not exist.

The snow was so thin, and the going so rough, that the sled went through three pairs of normal runners a day (at $40 a pair), so the team nailed on thick strips of roofing polyethylene instead. The huskies had to wear cloth boots, often three sets at a time, and wore out 7,000 of them.

The worst moment came on the afternoon of 23 December. After a splendid morning, on which they had covered 60 miles, mushing through the dawn, the team was on its way to an overnight rendezvous when their truck skidded on the ice of a logging trail, plunged down a 10-ft bank and landed on its side in waist-deep snow, smashing the engine block on a boulder and trapping half the huskies in their cubicles on the lower side of the box.

Wendy, fearing that the dogs would suffocate, thought, "That's it. The expedition's over." In fact, a tow-truck arrived to pull them out within half an hour; the huskies were none the worse, and after a 24-hour battle to reorganise their surviving vehicles, the team was back in action.

Her trek ended in partial disappointment. She had hoped to carry on far into the north west of Alaska and mush 1,600 miles along the Quest and Iditarod trails, which use frozen lakes and stretches of the Yukon River; but when she reached Whitehorse she found that the middle of the stream had already thawed, and Canadian Rangers strongly advised her not to try it. She therefore headed for Skagway, on the Pacific, and reached the sea - a twinkle of blue between spiky white mountains - on 15 March, four months to the day after setting out, with 4,410 miles behind her.

In making that tremendous effort, she saw many parallels with cancer treatment. "If you have a lot of obstacles to overcome, you have to keep your goal in mind," she says. "You have to stay determined, and keep going, regardless of how tough things get. That's why we found it so hard to stop when we did; we'd set out to show that we wouldn't be daunted by any difficulty, even if it seemed insurmountable."

Wendy now aims to write a book, and, come next winter, to be back in Alaska, to complete the eight-week trip down the Yukon to Nome, on the Bering Sea. "This could turn out to be just the final stage of my first trip," she says, "or it could be the second stage of a round-the-world mush". Next stop Siberia, then? Nobody who knows Wendy would put it past her.

Donations can be sent to the Imperial Cancer Research Fund at 2/3 Chancery House, Tolworth Close, Tolworth, Surrey KT6 7EW. Details of the expedition are available on the Dog-Trek website: www.dogtrek97-98.eu. inter.net