The horse (Equus caballus) is a hoofed one of eight living species of the family Equidae. The horse has evolved
over the past 45 to 55 million years from a small multi-toed creature into the large, Single-toed animal of today. Humans
began to domesticate horses around 4500 BC, and their domesticate is believed
to have been widespread by 3000 BC; by 2000 BC the use of domesticated horses had spread throughout the Eurasian
continent. Although most horses today are domesticated, there are still endangered populations of the Przewalski”s Horse,
the only remaining true wild horse, as well as more common Feral horses which live in the wild but are descended from domesticated
Horses are anatomically designed
to use speed to escape predators, and have a well-developed sense of balance and a strong fight-or-flight
instinct. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing
up and laying down. Female horses, called mares carry their young for approximately 11 months, and a young horse, called
a foal, can stand and run shortly following birth. Most horses begin training under saddle or in harness between the ages
of two and four. They reach full adult development by age five, and have an average lifespan of between 25 and 30 years.
Horse breeds are loosely divided
into three categories based on general temperament: spirited "hot bloods" with speed and endurance; "cold bloods," such as
draft horses and some ponies, suitable for slow, heavy work; and warnbloods developed from crosses between hot bloods and
cold bloods, often focusing on creating breeds for specific riding purposes, particularly in Europe. There are over 300 breeds
of horses in the world today, developed for many different uses. Horses and humans interact in many ways, not only in a wide
variety of sport competitions and non-competitive recreational pursuits, working activities including police work,
Many products are derived from horses,
including meat, milk, hide, hair, bone, and pharmaceuticals extracted from the urine of pregnant mares. Humans provide domesticated
horses with food, water and shelter, as well as attention from specialists such as veterinarians and farriers.
The English-speaking world measures the height of horses in hands, abbreviated
"h" or "hh," for "hands high," measured at the highest point of an animal's withers, where the neck meets the back, chosen
as a stable point of the anatomy, unlike the head or neck, which move up and down; one hand is 4 inches (10 cm).
Intermediate heights are defined by hands and inches, rounding to the lower measurement in hands, followed by a decimal point
and the number of additional inches between 1 and 3. Thus a horse described as "15.2 h," is 15 hands, 2 inches (62 in/160 cm)
in height.19 The size of horses varies by breed, but can also be influenced by nutrition Size varies greatly among horse breeds,
as with this full-sized horse and a miniature horse. Size varies greatly among horse breeds, as with this full-sized horse
and a miniature horse.
of a horse :Horses are adapted to grazing. In an adult horse, there are 12incisore,adapted
to biting off the grass or other vegetation, at the front of the mouth. There
are 24 teeth adapted for chewing, the premolars andmolars, at the back of the mouth. Stallions and geldings have four
additional teeth just behind the incisors, a type of canine teeth that are called "tushes." Some horses, both male and female,
will also develop one to four very smallvestigial teeth in front of the molars, known as "wolf" teeth, which are generally
removed because they can interfere with the bit. There is an empty interdental space between the incisors and the molars where
the bit rests directly on the bars (gums) of the horse's mouth when the horse is bridled.
Horses have an advanced sense of
taste that allows them to sort through grains and grasses to choose what they would most like to eat, and theirprehensile
lips can easily sort even the smallest grains. Horses generally will not eat poisonous plants. However, there are exceptions
and horses will occasionally eat toxic amounts of poisonous plants even when there is adequate healthy food.