The otters were lying in an uvver, or hollow, near the right bank, away from the tug of the cascade plunging down the fish-pass. The water in the uvver turned quietly. On its surface revolved a wheel of sticks, riveted by bubbles. The otters turned with it, hanging rudders down in the current. When the salmon leapt the weir, the bitch became rigid and her nostrils widened; but before the burst of the splash had dropped back, she had become supple again. The back of her sleek head gleamed and was gone. The cubs followed her, naturally so swift that a human observer might have wondered what cry or signal had been made by the otter. They swam by the bank until the pull of the water grew less, when the mother turned into midstream and sought the salmon by working upwater from bank to bank through the gloomy and tumultuous spate. The current forced them to swim with the webs of four feet. Tarka swam on her left flank and the other cub on her right. Sometimes he was flung sideways, or spun in another whirling wheel. He was swimming out of one when the bitch either scented the fish or saw the swift ream of its dorsal fin, for she turned and swam with the current, leaving them behind. Tarka turned after her, and was pursuing with all his strength when a narrow fish, larger than any he had ever seen, swished past him. A few moments afterwards the otter followed, but Tarka had to rise to breathe, and when he swam down again he was alone. He knew that hunted fish usually went upwater, so he swam against the current, swinging from side to side as he had learned by imitating his mother.