Ungulates are a group of large mammals that are distinguished from other animals by the presence of hooves. They are an extremely well-known and economically important group that include animals such as horses, camels, cows, sheep, goats, deer, pigs, giraffes, hippos, rhinos and many more.
Ungulate species are separated into two orders: Perissodactyla and Artiodactyla. The Perissodactyls are commonly known as the odd-toed ungulates and includes horses, rhinos and tapirs. The Artiodactyla consists of the even-toed ungulates and is a much larger order with around 220 different species. Cows, sheep, goats, buffalos, deer, giraffes, pigs and camels are just a few of the many even-toed ungulates that currently exist on Earth.
There is currently 16 species of Perissodactyls and they are distributed through Africa, Asia and the Americas. Most species live in either tropical or sub-tropical climates. A number of odd-toed ungulates are tremendous runners especially those from the family Equidae which includes horses, zebra, donkeys, onager and kiang.
The odd-toed ungulates digest their food using a method known as microbial fermentation. This method is efficient at digesting nutritious food but inefficient for digesting low quality food. Odd-toed ungulates are therefore only found in regions where food is abundant year round.
Horses, donkeys and zebras
Domestic individuals from the family Equidae, including horses and donkeys, are found almost anywhere human populations exist but wild populations are limited to Africa, the Middle East and parts of Asia. Wild equids tend to live in open habitats such as grasslands where predators are easier to spot and there is plenty of space for an escape. Horses are the greatest runners of the equids and have played an important role in human history.
The three species of zebra are all limited to Africa and are famous for their black and white stripes. Several hypotheses attempt to explain the function of the zebra’s stripes including causing confusion amongst predators, camouflage within tall grass, disturbing the sight of tsetse flies and helping to recognize individuals.
Rhinos are territorial herbivores and can weigh up to 3000 kg. There is five, possibly six, species belonging to the four different genera. Three species (black rhino, Javan rhino and Sumatran rhino) are critically endangered, while the remaining two are vulnerable (Indian rhino) and near threatened (white rhino).
The single genus of Tapirs has a total of five species which are found only in the Americas and southern Asia. The most characteristic feature of tapirs is their elongated trunk-like nose which is used to pick up leaves and as a snorkel while they are swimming. They are nocturnal animals and live in forests, generally not far from water. Three of the four species are endangered and the fourth, the lowland tapir (Tapirus terrestrus), is listed under the IUCN Red List as vulnerable.
The artiodactyls are found in every continent except Australia and Antarctica and in some of the coldest, hottest and driest environments on Earth. Most species are herbivorous and feed primarily on leaves. The even-toed ungulates have evolved arguably the best digestive system of any mammal in order to cope with the tough compounds found in the plant tissue they survive on.
Artiodactyls are a very diverse order of mammals with 240 species from 89 genera. Some species live in immense herds and take on great migrations such as the great wildebeest migration across the Serengeti of Africa. Many species of even-toed ungulates, such as cattle, sheep and deer, are of great economic importance and the foundations of multi-billion dollar industries.
The animals of the suborder Ruminantia, which includes all even-toed ungulates except the camel and pig families, have large chambered stomachs where food is held and undergoes microbial fermentation. Microorganisms in their stomachs possess enzymes that can split tough cellulose compounds found in plant tissue. The fermentation of food in the stomach by microbes improves digestion by releasing proteins, carbohydrates and lipids from plant tissue; and the nitrogen released during the breakdown of cellulose is used by gut microbes to produce proteins which are later digested in the animal’s intestines.
The bovids are the largest family of even-toed ungulates and the most economically important. Cows, sheep, goats, bison, buffalos, antelopes, ox and many other animals belong to this large family of 143 species. Wild species are found in Africa, Asia, Europe and North America while domesticated species occur almost wherever humans are found. They live primarily in grasslands feeding mostly on grasses.
All wild males grow horns and in some species so do females. One set of horns will span the entire life of an animal and in many species they will never stop growing until death. Other bovids include impalas, wildebeests, springboks, gazelles, ibex, tahr, chamois, oryx and waterbuck.
Deer and moose
Deer and moose belong to the family Carvidae which also includes elk, caribou and muntjacs. They are found naturally in all continents except Australia and Antarctica. They inhabit arctic to tropical environments and do particularly well in cold and mountainous regions. The cervids are characterized by their antlers which are grown annually. Apart from caribou, antlers are only found in males. Deer, moose and other cervids are all herbivores.
The hippopotamus is a large bulky ungulate that can weigh over 3000 kg. They are found only in Africa and spend the majority of their time in water; calves are even born and reared within the water. They live in groups and display complex levels of communication similar to whales. The hippopotamus belongs to the family Hippopotamidae which also includes the pygmy hippopotamus and is more closely related to whales and dolphins than any other ungulate family.
Pigs and their relatives
Suids are omnivorous and will often scavenge on dead and decaying animals. Pigs and other members of the family Suidae have large ever-growing canines and their upper canines create tusks. The largest suids can weigh up to 280 kg.
Llamas, alpacas and camels belong to the ungulate family Camelidae and are restricted primarily to dry environments such as deserts. Camels are found through Africa, the Middle East, India and Asia; and South America is home to llamas and alpacas. The largest camels can weigh up to 650 kg and all camelids have long necks and limbs. Camels are extremely well adapted to living in dry areas. In order to conserve water they produce dry faeces and very little urine.
- Hippos have skin glands that release a red oil to protect them from the sun. The oil often gives the impression that the hippo is sweating blood.
- Male giraffes can weigh almost 2 tonne but can still manage to run at speeds of up to 60 km/h (37 mph).
- Camels can remarkably go months without drinking any water.
Last edited: 10 November 2015