About Equus caballus Linnaeus, 1758
The domestic horse (Equus ferus caballus) is a domesticated, one-toed, hoofed mammal that belongs to the taxonomic family Equidae, and is one of two existing subspecies of Equus ferus. Over the past 45 to 55 million years, horses evolved from the small multi-toed Eohippus, originally native to North America, into the large single-toed animal we know today. Humans first began domesticating horses around 4000 BCE in Central Asia, and domestication was widespread by 3000 BCE. All members of the caballus subspecies are domesticated, though some domesticated horse populations live freely as feral horses. These feral groups are not true wild horses, which are defined as horses that have never been domesticated. An extensive specialized vocabulary exists to describe equine-related concepts, covering everything from anatomy, life stages, size, colors, markings, and breeds to locomotion and behavior. Horses are adapted for running to quickly escape predators, with a good sense of balance and a strong fight-or-flight response. Linked to this predator escape adaptation is an unusual trait: horses can sleep both standing up and lying down, and younger horses sleep significantly more than adult horses. Female horses, called mares, carry their young for approximately 11 months, and a young horse (called a foal) can stand and run shortly after birth. Most domesticated horses start training under a saddle or in a harness between the ages of two and four. They reach full adult development by age five, and have an average lifespan of 25 to 30 years. Horse breeds are loosely sorted into three categories by general temperament: spirited "hot bloods" with speed and endurance; "cold bloods" like draft horses and some ponies, suited for slow, heavy work; and "warmbloods", developed from crosses between hot bloods and cold bloods, often created for specific riding purposes, particularly in Europe. Today there are over 300 horse breeds worldwide, developed for many different uses. Humans and horses interact across a wide range of sport competitions, non-competitive recreation, and working activities including police work, agriculture, entertainment, and therapy. Historically, horses were used in warfare, which led to the development of a wide variety of riding and driving techniques, along with many different styles of equipment and control methods. Many commercial products are derived from horses, including meat, milk, hide, hair, bone, and pharmaceuticals extracted from the urine of pregnant mares. Gestation in horses lasts approximately 340 days, with an average range of 320 to 370 days, and usually produces a single foal; twins are rare. Horses are a precocial species, meaning foals are able to stand and run within a short time after birth. Foals are typically born in the spring. A mare's estrous cycle occurs roughly every 19 to 22 days, from early spring into autumn. Most mares enter an anestrus period during winter and do not cycle during this season. Foals are generally weaned from their mothers between four and six months of age. Horses, particularly young males (colts), are sometimes physically capable of reproduction at around 18 months, but domesticated horses are rarely allowed to breed before the age of three, especially females. Horses four years old are considered mature, though their skeleton normally continues developing until age six; maturation also depends on the horse's size, breed, sex, and quality of care. Larger horses have larger bones, so not only does bone tissue take longer to form, but the epiphyseal plates are larger and take longer to convert from cartilage to bone. These plates convert after other parts of the bones, and are critical to full development. Depending on the horse's maturity, breed, and expected work, horses are usually saddled and trained for riding between the ages of two and four. While Thoroughbred racehorses are put on the track as young as age two in some countries, horses bred for specific sports like dressage are generally not saddled until they are three or four years old, because their bones and muscles are not yet fully solidly developed. For endurance riding competition, horses are not considered mature enough to compete until they are 60 full calendar months (five years) old. People of all ages with physical and mental disabilities gain benefits from interacting with horses. Therapeutic riding is used to mentally and physically stimulate disabled people, helping them improve their lives through better balance and coordination, increased self-confidence, and a greater feeling of freedom and independence. The benefits of equestrian activity for people with disabilities have been formally recognized, with the addition of equestrian events to the Paralympic Games and recognition of para-equestrian events by the International Federation for Equestrian Sports (FEI). Hippotherapy and therapeutic horseback riding are different physical, occupational, and speech therapy treatment strategies that utilize the movement of a horse. In hippotherapy, a therapist uses the horse's movement to improve the patient's cognitive function, coordination, balance, and fine motor skills, while therapeutic horseback riding focuses on teaching specific riding skills. Horses also provide psychological benefits to people, even when the person does not ride them. "Equine-assisted" or "equine-facilitated" therapy is a form of experiential psychotherapy that uses horses as companion animals to help people with mental illness, including anxiety disorders, psychotic disorders, mood disorders, behavioral difficulties, and people going through major life changes. There are also experimental programs that use horses in prison settings; exposure to horses appears to improve inmates' behavior and reduce recidivism after they are released.
