When autumn set in, and hare-hunting began, they would often be on foot for twenty-four hours together without any food at all. As the boys grew older, they would follow the chase in winter on ski, often, indeed, almost to the detriment of their health. Once when they had been hare-hunting for a whole fortnight, they found their provision-bag was empty, and as they would not touch the hares they had killed, they had to subsist as best they could on potatoes only.
In this way Fridtjof grew up to be exceptionally hardy. When, as it often happened, his companions got worn out, he would suggest their going to some spot a long distance off. It seemed to be a special point of honor with him to bid defiance to fatigue. On one occasion, after one of these winter excursions to Nordmarken, he set off alone without any provisions in his knapsack to a place twenty-five kilometres (fifteen and a half miles) distant, for none of his companions dared accompany him. On arriving at the place where he was bound, he almost ate its inmates out of house and home.
On another occasion, on a long expedition on ski with some of his comrades, all of whom had brought a plentiful supply of food with them in their knapsacks, Fridtjof had nothing. When they halted to take some necessary refreshment, he unbuttoned his jacket and pulled out some pancakes from his pocket, quite warm from the heat of his body. "Here, you fellows," he said, "won't you have some pancakes?" But pancakes, his friends thought, might be nice things in general, yet pancakes kept hot in that way were not appetizing, and so they refused his proffered hospitality.
"You are a lot of geese! there's jam on them too," he said, as he eagerly devoured the lot.
Even as a boy Fridtjof was impressed with the idea that hardiness and powers of endurance were qualifications absolutely essential for the life he was bent on leading; so he made it his great aim to be able to bear everything, and to require as little as was possible.
If there were things others found impracticable, he would at once set to work and attempt them. And when once he had taken a matter in hand, he would never rest till he had gone through with it, even though his life might be at stake. For instance, he and his brother once set out to climb the Svartdal's peak in Jotunheim. [11] People usually made the ascent from the rear side of the mountain; but this was not difficult enough for him. He would climb it from the front, a route no one had ever attempted; and he did it.