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.
The dire wolf is an extinct canine. The dire wolf lived in the Americas during the Late Pleistocene and Early Holocene epochs. The species was named in 1858, four years after the first specimen had been found. Two subspecies are recognized: Aenocyon dirus guildayi and Aenocyon dirus dirus. The largest collection of its fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles.
Miohippus is an extinct genus of horse existing longer than most Equidae. It lived in what is now North America from 32 to 25 million years ago, during the late Eocene to late Oligocene. According to the Florida Museum of Natural History, Othniel Charles Marsh first believed Miohippus lived during the Miocene and thus named the genus using this incorrect conclusion. More recent research provides evidence that Miohippus actually lived during the Paleogene period.
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 most likely originated in North America and spread quickly to the Old World. 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.
Miracinonyx is an extinct genus of felids belonging to the subfamily Felinae that was endemic to North America from the Pleistocene epoch and morphologically similar to the modern cheetah, although its apparent similar ecological niches have been considered questionable due to anatomical morphologies of the former that would have limited the ability to act as a specialized pursuit predator. The genus was originally known from fragments of skeletons, but nearly complete skeletons have been recovered from Natural Trap Cave in northern Wyoming.
Equus scotti is an extinct species of horse native to Pleistocene North America.
Equus lambei, commonly known as the Yukon horse or Yukon wild horse, is an extinct species of the genus Equus. Equus lambei ranged across North America until approximately 10,000 years ago. Based on recent examinations of the mtDNA of Equus lambei remains, scientists have concluded that E. lambei was probably much like the extinct tarpan, also known as the Eurasian wild horse, and the living Przewalski's horse. A partial carcass of Equus lambei is on display at the Yukon Beringia Interpretive Centre in Whitehorse, Yukon.
Titanis is a genus of phorusrhacid, an extinct family of large, predatory birds, in the order Cariamiformes that inhabited the United States during the Pliocene and earliest Pleistocene. The first fossils were unearthed by amateur archaeologists Benjamin Waller and Robert Allen from the Santa Fe River in Florida and were named Titanis walleri by ornithologist Pierce Brodkorb in 1963, the species name honoring Waller. The holotype material is fragmentary, consisting of only an incomplete right tarsometatarsus and phalanx, but comes from one of the largest phorusrhacid individuals known. In the years following the description, many more isolated elements have been unearthed from sites from other areas of Florida, Texas, and California. It was classified in the subfamily Phorusrhacinae, which includes some of the last and largest phorusrhacids like Devincenzia and Kelenken.
Hippidion is an extinct genus of equine that lived in South America from the Late Pliocene to the end of the Late Pleistocene (Lujanian), between 2.5 million and 11,000 years ago. They were one of two lineages of equines native to South America during the Pleistocene epoch, alongside Equus (Amerhippus) neogeus.
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.
Pliohippus is an extinct genus of Equidae, the "horse family". Pliohippus arose in the middle Miocene, around 15 million years ago. The long and slim limbs of Pliohippus reveal a quick-footed steppe animal. While some specimens have one toe per leg, others have three.
Equus simplicidens, sometimes known as the Hagerman horse or the American Zebra is an extinct species of equine native to North America during the Pliocene and Early-Late Pleistocene. It is one of the oldest and most primitive members of the genus Equus. Abundant remains of it were discovered in 1928 in Hagerman, Idaho. It is the state fossil of Idaho.
Cormohipparion is an extinct genus of horse belonging to the tribe Hipparionini that lived in North America during the late Miocene to Pliocene. They grew up to 3 feet long.
Burnet Cave is an important archaeological and paleontological site located in Eddy County, New Mexico, United States within the Guadalupe Mountains about 26 miles west of Carlsbad.
Astrohippus is an extinct member of the Equidae tribe Equini, the same tribe that contains the only living equid genus, Equus. Fossil remains have been found in the central United States, Florida, and the Mexican states of Chihuahua, Jalisco, and Guanajuato. The fossils date in time from the oldest dating from the Barstovian in the Miocene to the youngest dating in the Hemphillian faunal stage of the early Pliocene.
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.
The Yunnan horse is an extinct species of equine that was present in East Asia during the Pleistocene very likely as a grazer on open tracts of grassland. It was a small equine comparable in size to the modern Przewalski's horse.
The Polk County paleontological sites are assemblages of Early Miocene to Late Pleistocene vertebrates occurring in Polk County, Florida, United States.
Horses have been an important component of American life and culture since before the founding of the nation. In 2008, there were an estimated 9.2 million horses in the United States, with 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.
The stay apparatus is an arrangement of muscles, tendons and ligaments that work together so that an animal can remain standing with virtually no muscular effort. It is best known as the mechanism by which horses can enter a light sleep while still standing up. The effect is that an animal can distribute its weight on three limbs while resting a fourth in a flexed, non-weight bearing position. The animal can periodically shift its weight to rest a different leg and thus all limbs are able to be individually rested, reducing overall wear and tear. The relatively slim legs of certain large mammals such as horses and cows would be subject to dangerous levels of fatigue if not for the stay apparatus.
