Horses' anatomy enables them to make use of speed to escape predators and they have a well-developed sense of balance and a strong fight-or-flight response.

Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down.

They can weigh from about 700 to 1,000 kilograms (1,540 to 2,200 lb).

They may have calmer temperaments than horses and also a high level of intelligence that may or may not be used to cooperate with human handlers.

Additional genes control suppression of black color to point coloration that results in a bay, spotting patterns such as pinto or leopard, dilution genes such as palomino or dun, as well as graying, and all the other factors that create the many possible coat colors found in horses.

Humans provide domesticated horses with food, water and shelter, as well as attention from specialists such as veterinarians and farriers.

Specific terms and specialized language are used to describe equine anatomy, different life stages, colors and breeds.

In English-speaking countries, the height of horses is often stated in units of hands and inches: one hand is equal to 4 inches (101.6 mm).

The height is expressed as the number of full hands, followed by a point, then the number of additional inches, and ending with the abbreviation "h" or "hh" (for "hands high").

It is an odd-toed ungulate mammal belonging to the taxonomic family Equidae.

The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, Eohippus, into the large, single-toed animal of today.

There are more than 300 breeds of horse in the world today, developed for many different uses.