Cursorial in the context of "Origin of avian flight"

The horse (Equus ferus caballus) is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of Equus ferus. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, Eohippus, into the large single-toed animal of today, originally in North America. Humans began domesticating horses around 4000 BCE in Central Asia, and their domestication is believed to have been widespread by 3000 BCE. Horses in the subspecies caballus are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, which are horses that have never been domesticated. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior.

Horses are adapted to run, allowing them to quickly escape predators, and possess a good sense of balance and a strong fight-or-flight response. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down, with younger horses tending to sleep significantly more than adults. Female horses, called mares, carry their young for approximately 11 months and a young horse, called a foal, can stand and run shortly following birth. Most domesticated horses begin training under a saddle or in a harness between the ages of two and four. They reach full adult development by age five, and have an average lifespan of between 25 and 30 years.

The limbs of the horse are structures made of dozens of bones, joints, muscles, tendons, and ligaments that support the weight of the equine body. They include three apparatuses: the suspensory apparatus, which carries much of the weight, prevents overextension of the joint and absorbs shock, the stay apparatus, which locks major joints in the limbs, allowing horses to remain standing while relaxed or asleep, and the reciprocal apparatus, which causes the hock to follow the motions of the stifle. The limbs play a major part in the movement of the horse, with the legs performing the functions of absorbing impact, bearing weight, and providing thrust. In general, the majority of the weight is borne by the front legs, while the rear legs provide propulsion. The hooves are also important structures, providing support, traction and shock absorption, and containing structures that provide blood flow through the lower leg. As the horse developed as a cursorial animal, with a primary defense mechanism of running over hard ground, its legs evolved to the long, sturdy, light-weight, one-toed form seen today.

Good conformation in the limbs leads to improved movement and decreased likelihood of injuries. Large differences in bone structure and size can be found in horses used for different activities, but correct conformation remains relatively similar across the spectrum. Structural defects, as well as other problems such as injuries and infections, can cause lameness, or movement at an abnormal gait. Injuries to and problems with horse legs can be relatively minor, such as stocking up, which causes swelling without lameness, or quite serious. Even leg injuries that are not immediately fatal may still be life-threatening to horses, as their bodies are adapted to bear weight on all four legs and serious problems can result if this is not possible.

Hyenas or hyaenas (/haɪˈiːnəz/ hi-EE-nəz; from Ancient Greek ὕαινα, hýaina) are feliform carnivoran mammals belonging to the family Hyaenidae (/haɪˈɛnɪdiː/). With just four extant species (each in its own genus), it is the fifth-smallest family in the order Carnivora and one of the smallest in the class Mammalia. Despite their low diversity, hyenas are unique and vital components of most African ecosystems.

Although phylogenetically closer to felines and viverrids, hyenas are behaviourally and morphologically similar to canids in several elements due to convergent evolution: both hyenas and canines are non-arboreal, cursorial hunters that catch prey with their teeth rather than claws. Both eat food quickly and may store it, and their calloused feet with large, blunt, nonretractable claws are adapted for running and making sharp turns. However, hyenas' grooming, scent marking, defecation habits, mating, and parental behavior are consistent with the behavior of other feliforms.

Hyaenodonta ("hyena teeth") is an extinct order of mostly carnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae. Hyaenodonts were important mammalian predators that are believed to have arose either in the Late Cretaceous or Early Paleocene within Europe, and persisted well into the Late Miocene. Hyaenodonts were found across Africa, Eurasia, and North America throughout the Cenozoic and occupied a variety of ecosystems, from forests to coastlines. They displayed a variety of body shapes, diet, and sizes. Ranging from ambush predators like Hyainailouros to Hyaenodon, in which some species were cursorial predators.

The order currently consists of three superfamilies, Hyaenodontoidae, Hyainailouroidea, and Limnocyonoidea, in addition to smaller groups such as the Galecyon clade. The hyaenodontoids consisted of Hyaenodontidae and Proviverrinae, the hyainailouroids consisted of Hyainailouridae, Prionogalidae, and Teratodontidae, and with the limnocyonoids consisted of Limocyoninae, Sinopinae, and Arfiinae.

Hyaenodon ("hyena-tooth") is an extinct genus of carnivorous placental mammals from the tribe Hyaenodontini, part of the subfamily Hyaenodontinae (which is within the family Hyaenodontidae), that belonged to the now extinct order Hyaenodonta. The genus was found lived in Eurasia and North America from the Middle Eocene to the Early Miocene, from 38 to 17 million years ago, existing for 21 million years. Hyaenodon first evolved in Asia, probably evolving from Propterodon.

The genus currently consists of at least 40 species, although due sexual dimorphism and intraspecific variation, they were likely fewer species within the genus. The species within the genus ranged in size from H. filholi, who weighed 2 kg (4.4 lb), to H. gigas and H. mongoliensis, who were estimated to be similar in size to Hyainailouros. The largest species were likely the apex predators of their time, with fossil records suggesting they could’ve occasionally hunted smaller predators. Several species within the genus were cursorial predators, either being ambushing or pounce-pursuit predators. The canines of the animal mediolaterally compressed much like canids, landing shallow bites on their prey. Unlike canids such as wolves, they were thought to have been solitary predators.

Eogruidae (also spelled Eogruiidae in some publications) is an extinct family of large, flightless birds that inhabited Asia from the Eocene to Pliocene epochs. Related to modern ostriches, it was formerly thought to be related to cranes, limpkins and trumpeters and that the similarities with ostriches were due to similar speciations to cursoriality, with both groups showing reduced numbers of toes to two in some taxa. It has been suggested that competition from true ostriches has caused the extinction of these birds, though this has never been formally tested and several ostrich taxa do occur in the late Cenozoic of Asia and some species do occur in areas where ostrich fossils have also been found. It has been suggested that the family is paraphyletic, with Ergilornithidae more closely related to modern ostriches than to Eogrus or Sonogrus.