ankle
The ankle, or the talocrural region, is the region where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at thi ...
s), cats, dogs, and many other mammal
Mammals (from Latin , 'breast') are a group of vertebrate animals constituting the class Mammalia (), and characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region ...
s, but not plantigrade
151px, Portion of a human skeleton, showing plantigrade habit
In terrestrial animals, plantigrade locomotion means walking with the toes and metatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrial mammals. The ...
s or unguligrade
Ungulates (pronounced ) are members of a diverse clade of primarily large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses and tapirs, and even-toed ungulates such as cattle, pigs, giraffes, camels, sheep, deer, ...
s. Digitigrades generally move more quickly and quietly than other animals.
There are anatomical differences between the limbs of plantigrades, like humans, and both unguligrade and digitigrade limbs. Digitigrade and unguligrade animals have relatively long carpals and tarsals, and the bones which would correspond to the human ankle are thus set much higher in the limb than in a human. In a digitigrade animal, this effectively lengthens the foot, so much so that what are often thought of as a digitigrade animal's "hands" and "feet" correspond only to what would be the bones
A bone is a rigid tissue that constitutes part of the vertebrate skeleton in animals. Bones protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobili ...
of the human finger or toe.
Humans usually walk with the soles of their feet on the ground, in plantigrade locomotion. In contrast, digitigrade animals walk on their distal
Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. Terms used generally derive from Latin or Greek roots and used to describe something in its standard anatomical position. This position provide ...
and intermediate phalanges
The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones.
St ...
. Digitigrade locomotion is responsible for the distinctive hooked shape of dog legs.
Unguligrade animals, such as horses and cattle, walk only on the distal-most tips of their digits, while in digitigrade animals, more than one segment of the digit makes contact with the ground, either directly (as in birds) or via paw-pads (as in dogs).
Examples
Skeleton of a wolf, showing a typical digitigrade arrangement of leg and foot bones *
Mesonychids
Mesonychia ("middle claws") is an extinct taxon of small to large-sized carnivorous ungulates related to the cetartiodactyls. Mesonychids first appeared in the early Paleocene, went into a sharp decline at the end of the Eocene, and died out enti ...
* Dinosaurs
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject ...
(digitigrade and semi-digitigrade)
** Birds
Birds are a group of warm-blooded vertebrates constituting the class Aves , characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skele ...
(except for loons
Loons (North America) or divers (United Kingdom / Ireland) are a group of aquatic birds found in many parts of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family Gaviidae and order Gaviifor ...
and grebes
Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed birds of freshwater, with some species also occurring in marine habitats during migration and winter. The order contains a single family, the Podicipe ...
which are plantigrade)
* Pigs
A pig is any of the animals in the genus ''Sus'', within the even-toed ungulate family Suidae. Pigs include domestic pigs and their ancestor, the common Eurasian wild boar (''Sus scrofa''), along with other species. Pigs, like all suids, are nat ...
(semi-digitigrade)
* Hippos
Hippos ( grc, Ἵππος, "horse") is an archaeological site in the Israel-Syria DMZ, on a hill in the northern Jordan Valley overlooking the Sea of Galilee. Between the 3rd century BCE and the 8th century CE, Hippos was the site of a Greco-Roman ...
(semi-digitigrade)
* ''Pakicetus
''Pakicetus'' is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Eocene, about 56 to 41 million years ago.. It was an animal about the size of a dog, which lived in or near the water and ...
''
* ''Indohyus
''Indohyus'' is a genus of extinct digitigrade artiodactyl known from Eocene fossils in Asia. This small chevrotain-like animal found in the Himalayas is one of the earliest-known non-cetacean relative of whales.
Description
DNA studies show a cl ...
''
* Thylacine
The thylacine ( , or , also ;) (''Thylacinus cynocephalus'') is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. It was the largest known carnivorous marsupial in the worl ...
* Cats
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is often referred to as the domestic cat to distinguish it from the wild members of the family. A cat ...
* Hyena
Hyenas, or hyaenas (from Ancient Greek , ), are feliform carnivoran mammals of the family Hyaenidae . With only four extant species (in three genera), it is the fifth-smallest biological family in the Carnivora and one of the smallest in the clas ...
s
* Mongooses
A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to sou ...
* Canids
Canidae (; from Latin, ''canis'', "dog") is a biological family of dog-like carnivorans. A member of this family is called a canid (). There are three subfamilies found within the canid family, which are the extinct Borophaginae and Hesperocyon ...
* Elephants
Elephants are the largest existing land animals. Three species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Elephantidae is the only surviving family of the order Proboscidea; extin ...
(semi-digitigrade)/ref> * Capybaras (semi-digitigrade) * '' Trucidocynodon'' (semi-digitigrade at least in the forelimbs)
References
External links
Yes, the Shin Bone Is Connected to the Ankle Bone
{{locomotion Terrestrial locomotion