They came from the left shore, and apparently were about as far off as the cry first heard.
"They are answers," said Fred, in a low voice, in which his companions detected a slight tremor.
It was at this moment that the first fear thrilled all three.

The cries might mean nothing, but more likely they meant a good deal.

The wolf is one of the fiercest of American wild animals when suffering from hunger, though a coward at other times, and a horde of them are capable of attacking the most formidable denizens of the woods.
The fact that they were between the skaters and home, and at no great distance from the course they must follow to reach there, was cause for fear.

It was almost certain that in some way the keen-scented creatures had learned there was game afoot that night for them, and they were signalling to each other to gather for the feast.
Fred and Monteith were not specially frightened on their own account, for, if the worst should come, they could take to the trees and wait for help.

They might make a sturdy fight, and perhaps, with anything like a show, could get away from them without taking to such a refuge.
But it was the presence of Jennie that caused the most misgiving.
True, she was as swift and skilful a skater as either, but that of itself was not likely to save her.
But she was the coolest of all, now that the danger assumed a reality.
The lightness and gayety that had marked the three from the moment of leaving home had gone.