Equus (genus)

_Equus_ (/ˈɛkwəs, ˈiːkwəs/) is a genus of mammals in the perissodactyl family Equidae, which includes horses, asses, and zebras. It is the only surviving genus in the Equidae family, with seven living species today. These animals have slender legs, long heads, long necks, manes, and tails. They eat plants and prefer to graze, having simpler stomachs than some other plant-eating animals.

Equines originated in North America and later spread to Africa, Asia, and South America during the Pleistocene epoch. Today, while domestic horses and donkeys are found all over the world, wild equines live mainly in Africa and Asia.

Wild equines live in two main social patterns. In one, a group includes one male, several females, and their young. In the other, males claim areas with food and water to attract females. In both patterns, females care for their babies, but males also help sometimes. These animals talk to each other using sounds and body language.

Human actions, such as building cities and changing land use, have made life harder for wild equines. Understanding these animals helps us protect them and learn more about their unique lives.

Etymology

The word equus comes from Latin and means "horse". It is related to the Greek word hippos, which also means "horse". Even older forms of the Greek word, like i-qo written in a very ancient script called Linear B, show how people long ago talked about horses.

Taxonomic and evolutionary history

Further information: Evolution of the horse

The genus Equus was first described by Carl Linnaeus. It is the only living genus in the family Equidae. Early equids were small, about the size of a dog, and lived around 54 million years ago during the Eocene. They had three toes on their back feet and four on their front feet, with small hooves instead of claws.

Over time, these animals grew larger and their side toes became smaller. By the time the genus Equus appeared, they had only one main toe on each foot. Equus evolved from an earlier form called Dinohippus. The oldest known Equus fossils were found in Idaho, USA, and soon after, they spread to Europe and Russia. Today, Equus includes all living horses, zebras, and donkeys.

Extant species

Prehistoric species

Many extinct species of Equus have been found in fossils. Some names may refer to the same animal, and scientists are still learning about them. Some of these prehistoric species include:

• American species

  • Equus alaskae – Alaskan horse
  • Equus conversidens – Mexican horse
  • Equus fraternus
  • Equus francisi – now placed in a separate genus, Haringtonhippus
  • Equus giganteus – Giant horse
  • Equus lambei – Yukon horse
  • Equus neogeus – often placed in a separate genus, Amerhippus
  • Equus niobrarensis – Niobrara horse
  • Equus occidentalis – Western horse
  • Equus scotti – Scott's horse
  • Equus semiplicatus
  • Equus simplicidens – Hagerman horse

• Eurasian species

  • Equus altidens
  • Equus major
  • Equus suessenbornensis
  • Equus livenzovensis
  • Equus senezensis
  • Equus dalianensis
  • Equus lenensis – Siberian horse
  • Equus latipes
  • Equus hydruntinus – European wild ass
  • Equus namadicus
  • Equus ovodovi
  • Equus yunnanensis
  • Equus stenonis – Stenon zebra
  • Equus sivalensis

• African species

  • Equus algericus
  • Equus capensis – Giant zebra
  • Equus mauritanicus – Saharan zebra

Domestic species

• Equus caballus – Domestic horse
• Equus asinus – Domestic donkey

Hybrids

Main article: Equid hybrid

Equine species can crossbreed with each other. The most common hybrid is the mule, a cross between a male donkey and a female horse. Another hybrid is the hinny, a cross between a male horse and a female donkey. Other hybrids include the zorse, a cross between a zebra and a horse, and a zonkey or zedonk, a hybrid of a zebra and a donkey.

Biology

Main articles: Equine anatomy and Horse behavior

Equines, which include horses, asses, and zebras, come in various sizes but all have long heads and necks, with slender legs that end in a single toe. Grévy's zebra is the largest wild species, while some miniature horses are very small. Equines are built for running long distances and have teeth suited for grazing.

Wild equines live in different parts of Africa and Asia, from grassy plains to dry deserts. They mainly eat grass but can also eat leaves, bark, and fruits when needed. These animals are social, often living in groups led by a male, and they communicate through sounds and body language. Females usually have one baby after a long pregnancy, and the mother cares for the young with help from the group when needed.

Human relations

The earliest evidence that people began to tame horses comes from places in Ukraine and Kazakhstan around 4000–3500 BCE. By 3000 BCE, horses were fully domesticated, and by 2000 BCE, many more horse bones appeared in settlements across northwestern Europe, showing that domesticated horses were spreading. Studies of genes show that just a few wild stallions, maybe all from one group, helped create the domestic horse by mating with many mares in early herds.

Humans have greatly affected wild equines like zebras and wild asses. Threats include losing their homes and conflicts with people and farm animals. Since the 20th century, wild equines have declined in many areas. Two subspecies, the quagga and the tarpan, have gone extinct. Some species are now endangered, such as Przewalski's horse, which was lost in the wild but brought back through breeding programs. In places like Australia and the United States, wild or "feral" horses cause debate. In the U.S., some have legal protection under the Wild and Free-Roaming Horses and Burros Act of 1971.