
(/Equus caballus/) is a large ungulate mammal, one of the seven modern species of the genus /Equus/. It has long played an important role in transport; whether ridden, pulling a chariot, carriage, horse-drawn boat, stagecoach, tram and also as plough horses. The most common date of domestication of the horse and its first use as a means of transport is circa 2000 BC. Until the mid 20th century, armies used horses extensively in warfare: soldiers still call the groups of machines that now take the place of the horse on the battlefield "cavalry" units.