Bruce and Langdon were sweating, and their smell came to him strongly.
For ten minutes Thor paid no attention to the eight dogs yapping at his heels, except to pause now and then and swing his head about.

As he continued in his retreat the Airedales became bolder, until finally one of them sprang ahead of the rest and buried his fangs in the grizzly's leg.
This accomplished what barking had failed to do.

With another roar Thor turned and pursued the pack headlong for fifty yards over the back-trail, and five precious minutes were lost before he continued upward toward the shoulder of the mountain.
Had the wind been in another direction the pack would have triumphed, but each time that Langdon and Bruce gained ground the wind warned Thor by bringing to him the warm odour of their bodies.

And the grizzly was careful to keep that wind from the right quarter.

He could have gained the top of the mountain more easily and quickly by quartering the face of it on a back-trail, but this would have thrown the wind too far under him.