Why did wolves come close to the men?

The wolves came close, particularly she She-Wolf, because they were hungry.

After a searching scrutiny, the animal trotted forward a few steps. This it repeated several times, till it was a short hundred yards away. It paused, head up, close by a clump of spruce trees, and with sight and scent studied the outfit of the watching men. It looked at them in a strangely wistful way, after the manner of a dog; but in its wistfulness there was none of the dog affection. It was a wistfulness bred of hunger, as cruel as its own fangs, as merciless as the frost itself.