Starting on the opposite side of the log that protected the spiny one's nose, he burrowed quickly through the snow and leaves.

The log was about three inches from the ground, and before the porcupine could realize it, the fisher had a space cleared and seized the spiny one by its soft, unspiny nose.

Grunting and squealing it pulled back and lashed its terrible tail.

To what effect?
Merely to fill the log around with quills.

With all its strength the quill-pig pulled and writhed, but the fisher was stronger.