A diamond will not dissolve in acid. The only thing that can destroy it is intense heat.

A dime has 118 ridges around the edge. A quarter has 119.

A donkey will sink in quicksand but a mule will not.

A dragonfly can fly 25 mph.

A dragonfly has a life span of 24 hours.

A dragonfly is also known as "devil's darning needle", "horse stinger" and "devil's steelyard".

A father Emperor penguin withstands the Antarctic cold for 60 days or more to protect his eggs, which he keeps on his feet, covered with a feathered flap. During this entire time he doesn't eat a thing. Most father penguins lose about 25 pounds while they wait for their babies to hatch. Afterward, they feed the chicks a special liquid from their throats. When the mother penguins return to care for the young, the fathers go to sea to eat and rest.