Scott Lefler, age 10, of Sioux City, Iowa, for his question:

WHY DOES A WHALE BLOW A SPOUT OF FOG?

Whales are mammals that live in the oceans. They aren't fish and must breathe air.

Sperm whales can stay under water from 45 minutes to an hour. Most baleen whales, however, only stay down from five to 10 minutes. Under water, a whale must hold his breath.

When a whale comes to the surface after a dive, the air in his lungs has become hot and full of moisture. As the whale reaches the surface, he blows out his breath. The hot breath hits the colder air and condenses, forming a spout or column of fog.

A baleen whale has two blowholes or nostrils on top of his head. A toothed whale has one blowhole.

You can learn to tell one whale from another at a distance by watching the spouts. Some spouts are tall and thick while others are low.