"I should think it would kill them." "It would kill you, of course, in about two minutes," replied Uncle Andy.

"But they are built differently.

They have a handy way of doing up a lot of breathing all at once, and then not having to think any more about it for a while.

You can readily see what a convenience that might be to them.
"When they got back to the surface, they lay comfortably rocking among the green swells, while they both blew all the used-up air and steam out of their lungs.

The feathery little jet of the calf rose gravely beside his mother's high and graceful spout.