White Fang by Jack London, Fiction, Classics

A second cry arose, piercing the silence with needlelike shrillness. Both men located the sound. It was to the rear, somewhere in the snow expanse they had just traversed. A third and answering cry arose, also to the rear and to the left of the second cry. "They're after us, Bill," said the man at the front. His voice sounded hoarse and unreal, and he had spoken with apparent effort. "Meat is scarce," answered his comrade. "I ain't seen a rabbit sign for days." Thereafter they spoke no more, though their ears were keen for the hunting-cries that continued to rise behind them.