And when Dagger Bill took to hunting Water Babies, it was no longer safe for them to play far from home.

They would get themselves well nipped by their relations, I can tell you, whenever they went outside the little patch of shallow water between the house and the bank.
"Now the sharpness of Dagger Bill's eyes was something terrible.

From away across the lake, where no muskrat could see him at all, _he_ could see the ripple made by the brown nose of the littlest muskrat swimming.
So one day, when the Water Babies were playing tag in what was really, you know, nothing more nor less than their own back yard, he saw the swift ripples and splashes crossing and recrossing--and he laughed! _You_ know how he laughed.
"And when the muskrats heard that wild laughter, they bobbed up their furry heads, those in the water; and those on land sat up like squirrels to listen, and all were as delighted as possible because the sound was so very far away! Then the Water Babies all began to play about as boldly as you please, because they knew Dagger Bill was away over at the other side of the lake.
"But do you suppose he really was?
"Not much! The moment he was done laughing he dived, and swam as hard as he could straight across the lake, under water.

He swam and he swam, a sharp, black-and-white wedge rushing through the golden deep, as long as he could hold his breath.

When he could not hold it a moment longer he came up, stuck his bill just above water, took a long breath, and dived again.