Equidae is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. The family evolved around 50 million years ago from a small, multi-toed ungulate into larger, single-toed animals. All extant species are in the genus Equus, which originated in North America. Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families. It is more specifically grouped within the superfamily Equoidea, the only other family being the extinct Palaeotheriidae.
Megatherium is an extinct genus of ground sloths endemic to South America that lived from the Early Pliocene through the end of the Late Pleistocene. It is best known for the elephant-sized type species Megatherium americanum, primarily known from the Pampas, but ranging southwards to northernmost Patagonia and northwards to southern Bolivia during the late Middle Pleistocene and Late Pleistocene. Various other species belonging to the subgenus Pseudomegatherium ranging in size comparable to considerably smaller than M. americanum are known from the Andean region.
Equus is a genus of mammals in the family Equidae, which includes horses, asses, and zebras. Within the Equidae, Equus is the only recognized extant genus, comprising seven living species. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. The genus originated in North America and dispersed into the Old World and South America during the Early and Middle Pleistocene. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes, and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants but able to subsist on lower-quality vegetation.
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c. 11,700 years ago. The late Pleistocene equates to the proposed Tarantian Age of the geologic time scale, preceded by the officially ratified Chibanian. The beginning of the Late Pleistocene is the transition between the end of the Penultimate Glacial Period and the beginning of the Last Interglacial around 130,000 years ago. The Late Pleistocene ends with the termination of the Younger Dryas, some 11,700 years ago when the Holocene Epoch began.
Macrauchenia is an extinct genus of large ungulate native to South America from the Pliocene or Middle Pleistocene to the end of the Late Pleistocene. It is a member of the extinct order Litopterna, a group of South American native ungulates distinct from the two orders which contain all living ungulates which had been present in South America since the early Cenozoic, over 60 million years ago, prior to the arrival of living ungulates in South America around 2.5 million years ago as part of the Great American Interchange. The bodyform of Macrauchenia has been described as similar to a camel, being one of the largest-known litopterns, with an estimated body mass of around 1 tonne. The genus gives its name to its family, Macraucheniidae, which like Macrauchenia typically had long necks and three-toed feet, as well as a retracted nasal region, which in Macrauchenia manifests as the nasal opening being on the top of the skull between the eye sockets. This has historically been argued to correspond to the presence of a tapir-like proboscis, though recent authors suggest a moose-like prehensile lip or a saiga antelope-like nose to filter dust are more likely.
The wild horse is a species of the genus Equus, which includes as subspecies the modern domesticated horse as well as the endangered Przewalski's horse. The European wild horse, also known as the tarpan, that went extinct in the late 19th or early 20th century has previously been treated as the nominate subspecies of wild horse, Equus ferus ferus, but more recent studies have cast doubt on whether tarpans were truly wild or if they actually were feral horses or hybrids.
Doedicurus is an extinct genus of glyptodont from South America containing one species, D. clavicaudatus. Glyptodonts are a member of the family Chlamyphoridae, which also includes some modern armadillo species, and they are classified in the superorder Xenarthra alongside sloths and anteaters. Being a glyptodont, it was a rotund animal with heavy armor and a carapace. Averaging at an approximate 1,400 kg (3,100 lb), it was one of the largest glyptodonts to have ever lived. Though glyptodonts were quadrupeds, large ones like Doedicurus may have been able to stand on two legs like other xenarthrans. It notably sported a spiked tail club, which may have weighed 40 or 65 kg in life, and it may have swung this in defense against predators or in fights with other Doedicurus at speeds of perhaps 11 m/s.
The European wild ass or hydruntine is an extinct equine from the Middle Pleistocene to Late Holocene of Europe and West Asia, and possibly North Africa. It is a member of the subgenus Asinus, and closely related to the living Asiatic wild ass. The specific epithet, hydruntinus, means from Otranto.
The evolution of the horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the modern horse. Paleozoologists have been able to piece together a more complete outline of the evolutionary lineage of the modern horse than of any other animal. Much of this evolution took place in North America, where horses originated but became extinct about 10,000 years ago, before being reintroduced in the 15th century.
Equus simplicidens, also known as the Hagerman horse is an extinct species of equine native to North America during the Pliocene and Early Pleistocene. It is one of the oldest and most primitive members of the genus Equus. It is the state fossil of Idaho, where abundant remains of the species were discovered near the town of Hagerman in 1928.
The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafauna, which resulted in a collapse in faunal density and diversity across the globe. The extinctions during the Late Pleistocene are differentiated from previous extinctions by its extreme size bias towards large animals, and widespread absence of ecological succession to replace these extinct megafaunal species, and the regime shift of previously established faunal relationships and habitats as a consequence. The timing and severity of the extinctions varied by region and are thought to have been driven by varying combinations of human and climatic factors. Human impact on megafauna populations is thought to have been driven by hunting ("overkill"), as well as possibly environmental alteration. The relative importance of human vs climatic factors in the extinctions has been the subject of long-running controversy.
Glyptodon is a genus of glyptodont, an extinct group of large, herbivorous armadillos, that lived from the Pliocene, around 3.2 million years ago, to the early Holocene, around 11,000 years ago, in South America. It is one of, if not the, best known genus of glyptodont. Glyptodon has a long and storied past, being the first named extinct cingulate and the type genus of the subfamily Glyptodontinae. Fossils of Glyptodon have been recorded as early as 1814 from Pleistocene aged deposits from Uruguay, though many were incorrectly referred to the ground sloth Megatherium by early paleontologists.
Haringtonhippus is an extinct genus of equine from the Pleistocene of North America The genus is monospecific, consisting of the species H. francisci, initially described in 1915 by Oliver Perry Hay as Equus francisci. Members of the genus are often referred to as stilt-legged horses, in reference to their slender distal limb bones, in contrast with those of contemporary "stout legged" caballine true horses.
Catonyx is an extinct genus of ground sloth of the family Scelidotheriidae, endemic to South America during the Pliocene and Pleistocene epochs. It lived from 2.5 Ma to about 10,000 years ago, existing for approximately 2.49 million years. The most recent date obtained is about 9600 B.P.
Equinae is a subfamily of the family Equidae, known from the Hemingfordian stage of the Early Miocene onwards. They originated in North America, before dispersing to every continent except Australia and Antarctica. They are thought to be a monophyletic grouping. Members of the subfamily are referred to as equines; the only extant equines are the horses, asses, and zebras of the genus Equus, with two other genera Haringtonhippus and Hippidion becoming extinct at the beginning of the Holocene, around 11–12,000 years ago.
Notiomastodon is an extinct genus of gomphothere proboscidean, endemic to South America from the Pleistocene to the beginning of the Holocene. Notiomastodon specimens reached a size similar to that of the modern Asian elephant, with a body mass of 3-4 tonnes. Like other brevirostrine gomphotheres such as Cuvieronius and Stegomastodon, Notiomastodon had a shortened lower jaw and lacked lower tusks, unlike more primitive gomphotheres like Gomphotherium.
Equus neogeus is an extinct species of equine native to South America during the Pleistocene. It was formerly thought to be several distinct species within the subgenus Amerhippus, but was later shown to be a single morphologically variable species. It is thought to be closely related to true horses.
Horses have been an important component of American life and culture since before the founding of the nation. In 2023, there were an estimated 6.65 million horses in the United States, with 1.5 million horse owners, 25 million citizens that participate in horse related activities, 12 million citizens that spectate at horse events, and 4.6 million citizens involved in businesses related to horses. There are an estimated 82,000 feral horses that roam freely in the wild in certain parts of the country, mostly in the Western United States.
Equus stenonis is an extinct species of equine that lived in Western Eurasia including Europe during the Early Pleistocene.
Fishtail points, also known as Fell points are a style of Paleoindian projectile point widespread across much of South America at the end of the Late Pleistocene, around 13-12,000 years ago. They are thought to have been multifunctional, serving as cutting tools, as well as hafted to spears to use as hunting weapons, possibly in combination with spear throwers.
