The term “ungulate” refers to a hoofed grazing mammal. There are multiple kinds of animals called ungulates, and the majority of them move by supporting their entire body weight on the tips of their toes, which are typically hoofed. Of the six to eight mammalian orders that still exist, they make up several. Horses, deer, antelopes, cattle, camels, rhinoceroses, tapirs, giraffes, pigs, and hippopotamuses are some examples of ungulates that are still alive today.
For a very long time, “ungulates” were not classified according to the shape of their hooves but rather according to their affinity for an extinct ancestor. The morphological family tree was the generally accepted way to categorise animals, and it was constantly being adjusted as more fossil data came to light. (The place of cetaceans next to Artiodactyla was eventually settled in the late 1990s.)
Recent advances in molecular science, which depend more on genetic similarity than on external traits, have revealed a radically different picture of the relationships between the major groupings of mammals. The Ungulata, a traditional mammal clade, is now acknowledged as a paraphyletic grouping, meaning that some but not all of its members share a common ancestor.
The Proboscidea (elephants), Sirenia (manatees and dugongs), and Cetacea (whales and dolphins) are only a few of the species of living hoofed mammals that share a common ancestor with the two families of hoofed mammals that have hooves today. Since both major families have evolved digitigrade locomotion with larger claws that create hoofs, it is sometimes more practical to refer to them as “ungulates.”
The Artiodactyla, or mammals with cloven hooves, and the Perissodactyla, or mammals with odd-toed feet, are the two main suborders of extant mammals with hooves. With more than a hundred live species, including well-known animals like sheep, goats, camels, pigs, cows, deer, and antelopes, the former is by far the bigger of the two groupings.
There are just seventeen surviving species in the Perissodactyla, which are divided into three subgroups: horses, rhinoceroses, and tapirs. Perissodactyls were far more varied in the early Cenozoic, including the enormous extinct brontotheres and Indricotherium, the biggest terrestrial animal ever.
In grasslands and savannahs, there are numerous hoofed mammals. Ungulates have developed traits that are adapted for life on open grasslands, including large legs to accelerate movement. Ungulates developed digitigrade locomotion, or walking on their toes, to extend the legs. Anatomically, the hoof of a horse or cow has an expanded toe.
Artiodactyl animals like deer, lambs, and goats walk on two toes, while perissodactyl animals like rhinos, tapirs, and some extinct horses walk on three toes or only one toe. Most ruminants and rhinos fully lose their remaining toes, whereas pigs and tapirs only use a portion of their remaining toes for walking. To grind their food from grasses and other plants, many ungulates have evolved huge, intricately grooved molar teeth.
Content for this question contributed by Lisa Fanin, resident of Pomona, eastern Los Angeles County, California, United States, USA
