Phil Arlington, age 7, of Columbus, Ohio, for his question:

HOW LONG DOES A HORSE LIVE?

Horses live to be about 20 to 30 years of age.

All race horses have their official birthday on Jan. 1, except in Australia and New Zealand where it is on Aug. 1. Regardless of the actual birth date, race horses become a year older on their official birthday.

This system of giving horses one birthday is used to qualify them for races limited to certain age groups. As an example, only 3 year olds are allowed to race in the famous Kentucky Derby each May.

A female horse carries her baby, or foal, for about 11 months before giving birth. Foals can stand on their own four legs shortly after birth, and within a few hours they are able to run about.

The legs of newborn horses seem much too long for their bodies. As the horse matures, the legs grow more slowly than the rest of the body.

A year old colt is about half grown. Most horses reach full height and weight by the age of 5. Most horsemen breed female horses, or "mares" as they are called, before the age of 4. Most mares have five or six foals during their lives, but some have had as many as 19.