He wanted to reply, but some strange instinct urged him not to.
That instinct of the wild was already becoming master of him.

In the air, in the whispering of the spruce-tops, in the moon and the stars themselves, there breathed a spirit which told him that what he had heard was the wolf-cry, but that it was not the wolf _call_.
The other came an hour later, clear and distinct, that same wailing howl at the beginning--but ending in a staccato of quick sharp yelps that stirred his blood at once into a fiery excitement that it had never known before.

The same instinct told him that this was the call--the hunt-cry.

It urged him to come quickly.

A few moments later it came again, and this time there was a reply from close down along the foot of the ridge, and another from so far away that Kazan could scarcely hear it.