Without knowing it, Baree was burying himself deeper and deeper into Tusoo's old trapping grounds.

Since Tusoo had died, they had lain undisturbed except for the wolves, for Gray Wolf and Kazan had not hunted on this side of the waterway--and the wolves themselves preferred the more open country for the chase.
Suddenly Baree found himself at the edge of a deep, dark pool in which the water lay still as oil, and his heart nearly jumped out of his body when a great, sleek, shining creature sprang out from almost under his nose and landed with a tremendous splash in the center of it.

It was Nekik, the otter.
The otter had not heard Baree, and in another moment Napanekik, his wife, came sailing out of a patch of gloom, and behind her came three little otters, leaving behind them four shimmering wakes in the oily-looking water.

What happened after that made Baree forget for a few minutes that he was lost.

Nekik had disappeared under the surface, and now he came up directly under his unsuspecting mate with a force that lifted her half out of the water.