Birds

Larger birds use their wings less. The smallest known bird, the hummingbird, beats its wings about 90 times a second. The largest bird, the ostrich, does not use its wings at all. The hummingbird is the only bird that can fly backwards. In one day, it uses in proportion to its size a little over 44 times as much energy as an average man. It lays the smallest egg, less than 1/2 inch. A penguin will build a rough nest out of stones sometimes. Birds rarely sing, when standing on the ground. Flamingoes turn pink, when they are digesting blue-green algae.

Swimming

Polar bears are excellent swimmers and can also run fast on land, reaching 25 miles per hour. Kangaroos are stong swimmers, too.

Taken from Weird & Wonderful Science Facts, Magnus Pyke, Sterling Publishing Co., N.Y. N.Y. 1984