Australopiths, which were bipedally adept and occasionally climbed trees, were precursors to human ancestors like Neanderthals.
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Gorillas and chimpanzees can walk bipedally for short periods of time, but they're not doing it to the extent that humans are.
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Furthermore, some exhibit a bipedal stance for some behaviour and may walk a few steps bipedally. Pangolins are also good swimmers.
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Among arthropods, cockroaches are known to move bipedally at high speeds. Bipedalism is rarely found outside terrestrial animals, though at least two types of octopus walk bipedally on the sea floor using two of their arms, allowing the remaining arms to be used to camouflage the octopus as a mat of algae or a floating coconut.
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All primates possess some bipedal ability, though most species primarily use quadrupedal locomotion on land. Primates aside, the macropods (kangaroos, wallabies and their relatives), kangaroo rats and mice, hopping mice and springhare move bipedally by hopping. Very few mammals other than primates commonly move bipedally by an alternating gait rather than hopping. Exceptions are the ground pangolin and in some circumstances the tree kangaroo.
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Pantydraco is considered to have most probably been omnivorous, being at the transition from carnivory to herbivory in the sauropodomorph lineage. It is probable that Pantydraco would have walked bipedally.
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Sifakas can locomote bipedally in two separate ways: walking, with an evenly spaced gait and no aerial phase; or galloping, switching the trailing and leading foot every 5-7 steps. Propithecus and humans are the only species known to use a skipping/galloping type of locomotion. Ring-tailed lemurs (Lemur catta), can be arboreal or terrestrial. While terrestrial, they move quadrupedally 70% of the time, bipedally 18% of the time, and by leaping the remaining 12% of the time.
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Unlike modern macropodids, which hop (either bipedally or quadrupedally), sthenurines seem to have abandoned saltation as a means of locomotion. Their comparatively inflexible spines, robust hindlimb and pelvic elements, and the lack of capacity for rapid hopping suggest that these animals walked bipedally, somewhat like hominids, even converging with those primates in details of their pelvic anatomy. Furthermore, their hooved single digits and metatarsal anatomy suggest that unlike their plantigrade relatives, sthenurines were unguligrade, walking on the tips of their "toes".
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Like other hadrosaurs, it could have moved both bipedally and quadrupedally. Comparisons between the scleral rings of Prosaurolophus and modern birds and reptiles suggest that it may have been cathemeral, active throughout the day at short intervals.
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Chimpanzees exhibit bipedalism most often when carrying valuable resources (such as food gathering/transporting) because chimps can carry more than twice as much when walking bipedally as opposed to walking quadrupedally. Bipedalism is practiced both on the ground and up high when feeding from fruit trees. Foraging for food in the shorter trees while standing bipedally allows for the chimps to reach higher up so they can get food more easily. In orangutans, bipedalism is more often considered an extension of "orthograde clamber" rather than an independent form of locomotion.
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Birth rarely occurs during the day or on the ground. During labor the female isolates herself from the group (about 100 m). The mother stands bipedally during parturition and assists the delivery with her hands. The infant is usually born 2 minutes after crowning.
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However, research has shown that bipedal locomotion does not increase speed but can increase acceleration. It is also possible that facultative bipedalism is a physical property of the lizard's movement rather than a developed behavior. In this scenario, it would be more energetically favorable to allow the forelimbs to rise with the rotation caused by the lizard's acceleration rather than work to keep the forelimbs on the ground. Recent research has shown that the actual acceleration at which lizards begin to run bipedally is lower than the previous model predicted, suggesting that lizards actively attempt to locomote bipedally rather than passively allow the behavior to occur.
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Like other hadrosaurs, they could have moved both bipedally and quadrupedally. The extensive depressions surrounding its nasal openings may have hosted nasal diverticula. These postulated diverticula would have taken the form of inflatable soft-tissue sacs. Such sacs could be used for both visual and auditory signals.
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Basilisks sometimes run bipedally. Basilisks have the ability to "run" on water, and because of this, they have been dubbed the "Jesus Christ lizard" in reference to the biblical passage of Matthew 14:22-34.How "Jesus Lizards" Walk on Water. News.nationalgeographic.com. Retrieved on 2010-08-19.
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Based on the structure of the hind limbs and pelvic girdle of Aardonyx, the dinosaur normally moved bipedally but could drop to quadrupedal movement similar to Iguanodon. It shares some attributes with giant quadrupedal sauropods like Apatosaurus.Associated Press (November 11, 2009). Scientists: New dinosaur species found in South AfricaNPR.
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If this is true, there may be some advantage associated with bipedalism that has not yet been identified. Alternatively, while the origin of the behavior may have been solely the physical motion and acceleration, traveling bipedally may have conferred an advantage, such as easier maneuvering, that was then exploited.
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Energy-efficient means of standing bipedally involve constant adjustment of balance, and of course these must avoid overcorrection. The difficulties associated with simple standing in upright humans are highlighted by the greatly increased risk of falling present in the elderly, even with minimal reductions in control system effectiveness.
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Lucy developed the ability to walk on 2 legs (bipedally) across grassland to cope with naturally occurring deforestation. By standing upright, Lucy could see further than other apes as a defence against predators. Coincidentally, this adaption freed up the hands for later tool use. In 1996 the investigation went high tech.
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A capuchin monkey standing on two legs. Capuchin monkeys are arboreal quadrupeds, but can locomote bipedally on the ground. They use a spring-like walk that lacks an aerial phase. While humans employ a pendulum-like gait which allows for the interchange of kinetic and potential energy, capuchins do not.
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Chimpanzees are adapted for both arboreal and terrestrial locomotion. Arboreal locomotion consists of vertical climbing and brachiation. On the ground chimps move both quadrupedally and bipedally, which appear to have similar energy costs. As with bonobos and gorillas, chimps move quadrupedally by knuckle-walking, which probably evolved independently in Pan and Gorilla.
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Tenkiles have a noticeably long snout, and these kangaroos are able to hop and walk bipedally. They are also able to raise their arms above their head, all of which normal kangaroos cannot.It is believed that this species possibly breeds year round with a young born each year. The young become independent after two years.
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Like all apes, gibbons are tailless. Unlike most of the great apes, gibbons frequently form long-term pair bonds. Their primary mode of locomotion, brachiation, involves swinging from branch to branch for distances up to , at speeds as high as . They can also make leaps up to , and walk bipedally with their arms raised for balance.
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A sifaka galloping bipedally. The Sifaka (Propithecus) which is a type of lemur native to the island of Madagascar, is one of the primary examples of facultative bipedalism. While moving through the trees, they locomote using a vertical clinging and leaping strategy. On the ground, they can walk on their two hind legs as a way to conserve energy.
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Australopithecines also have short hind limbs for their weight and height, which also shows a higher energy expenditure when walking bipedally. This indicates that this species practiced bipedal locomotion, but did so more infrequently than previously thought. At the times they did practice bipedalism, the benefits outweighed the potential costs that would be imposed on them.
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Melissa (ca. 1950–1986) was a high-ranking female and mother of long-term alpha male Goblin. Researchers also suspected that she was related to alpha male Humphrey and another male, Mr McGregor. She was afflicted by polio in the 1966 epidemic, and for a while was paralyzed in her neck and shoulders, and was forced to walk bipedally.
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There is an unconfirmed record of another individual, shot in 1932, that was and weighed . The heaviest silverback recorded was a specimen shot in Ambam, Cameroon, which weighed . The mountain gorilla is primarily terrestrial and quadrupedal. However, it will climb into fruiting trees if the branches can carry its weight, and it is capable of running bipedally up to .
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Kangaroo rats move bipedally. Kangaroo rats often leap a distance of 6 feet, and reportedly up to 9 feet (2.75 m) at speeds up to almost 10 feet/sec, or 10 km/h (6 mph). They can quickly change direction between jumps. The rapid locomotion of the banner-tailed kangaroo rat may minimize energy cost and predation risk.
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Ground squirrels and meerkats will stand on hind legs to survey their surroundings, but will not walk bipedally. Dogs (e.g. Faith) can stand or move on two legs if trained, or if birth defect or injury precludes quadrupedalism. The gerenuk antelope stands on its hind legs while eating from trees, as did the extinct giant ground sloth and chalicotheres.
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Bipedalism is unknown among the amphibians. Among the non-archosaur reptiles bipedalism is rare, but it is found in the 'reared-up' running of lizards such as agamids and monitor lizards. Many reptile species will also temporarily adopt bipedalism while fighting. One genus of basilisk lizard can run bipedally across the surface of water for some distance.
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These include Shuangmiaosaurus from the early Late Cretaceous of Liaoning Province of northeastern China, and two other early Late Cretaceous taxa from North America: the Cenomanian Protohadros and the Turonian Jeyawati. Like other hadrosauroids, Yunganglong was a ground-dwelling herbivore that could walk bipedally, and could stand on all four legs. The skull of Yunganglong is relatively wide and low.
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Lizard Island: Cuba is a study in saurian richness. Retrieved 15 March 2018. It can also run bipedally across water, similar to A. lionotus, A. poecilopus and A. oxylophus (all often in Norops instead) from Central America and Colombia, as well as the basilisks. A. vermiculatus feeds on small animals like frogs, shrimp and fish, which often are caught in water.
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Some quadrupeds are able to walk bipedally on their forelimbs, thus performing "hand" walking in an anthropomorphic sense. For example, when attacked, the spotted skunk may rear up and move about on its forelimbs so that its anal glands, capable of spraying an offensive oil, are directed towards the attacker. Dogs and sealions can also be trained to walk on their forelimbs.
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However, it probably spent most of its time on all fours, only moving bipedally when it needed to run rapidly. Its skull also resembled those of theropod dinosaurs, but more primitive features included the presence of five toes on each foot and a double row of armoured plates along the animal's back. Ornithosuchus has traditionally been estimated at a length of about around .
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Woolly monkeys also brachiate at times. Orangutans use a similar form of locomotion called quadramanous climbing, in which they use their arms and legs to carry their heavy bodies through the trees. Chimpanzees and gorillas knuckle walk, and can move bipedally for short distances. Although numerous species, such as australopithecines and early hominids, have exhibited fully bipedal locomotion, humans are the only extant species with this trait.
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With their hooked hands, they can move swiftly with great momentum, swinging from the branches. Although they rarely come to the ground naturally, while there, they walk bipedally with arms raised above their heads for balance. Their social organization is dominated by monogamous family pairs, with one breeding male and one female along with their offspring. When a juvenile reaches sexual maturity, it is expelled from the family unit.
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Adhesive pads enable geckos to climb vertically. Aside from legless lizards, most lizards are quadrupedal and move using gaits with alternating movement of the right and left limbs with substantial body bending. This body bending prevents significant respiration during movement, limiting their endurance, in a mechanism called Carrier's constraint. Several species can run bipedally, and a few can prop themselves up on their hindlimbs and tail while stationary.
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Yunnanosaurus ( ) is an extinct genus of sauropodomorph dinosaur that lived approximately 201 to 168 million years ago in what is now the Yunnan Province, in China. Yunnanosaurus was a large sized, moderately-built, ground-dwelling, quadrupedal herbivore, that could also walk bipedally, and ranged in size from 7 meters (23 feet) long and 2 m (6.5 ft) high to 4 m (13 ft) high in the largest species.
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The entire sequence has nine steps: (1) progressively quickening hooting, (2) symbolic feeding, (3) rising bipedally, (4) throwing vegetation, (5) chest-beating with cupped hands, (6) one leg kick, (7) sideways running four-legged, (8) slapping and tearing vegetation, and (9) thumping the ground with palms . Jill Donisthorpe has stated that a male charged at her twice. In both cases, the gorilla turned away when she stood her ground.
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Second, due to an inherited recessive genetic mutation, they have a non-progressive congenital cerebellar ataxia that impairs the balance children normally use to learn to walk bipedally. Not being able to manage the balance needed for bipedal walking, they perfected in its place their initial bear-crawl into an adult quadruped gait. The family's walking likely has nothing to do with genes involved in the human evolution of upright walk.
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Immature baboons seem to be more bipedal than adults. These bipedal postures and locomotion in infants, although infrequent, seem to clearly distinguish them from adult baboons in terms of maturity level. In the wild, locomotor behavior of these baboons vary as a result of their need to find food and to avoid predators. Gelada baboons use what's known as a "shuffle gait", where they squat bipedally and move their feet in a shuffling motion.
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Although no longer extant, Australopithecines exhibited facultative bipedalism. Their pelvis and lower body morphology are indicative of bipedalism: the lumbar vertebrae curve inward, the pelvis has a human-like shape, and the feet have well-developed transverse and longitudinal arches that indicate walking. However, other features indicate reduced locomotor competence, or an increase in stress caused by walking bipedally. The pelvis is broad, which requires greater energy to be used during walking.
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In 2004 he initiated and was a consultant for the BBC documentary The Family That Walks On All FoursThe Family That Walks On All Fours, Passionate Productions, first broadcast BBC2, Friday 17 March 2006 that reported on the Ulas family, the first humans reported that could not walk bipedally but who were proficient quadrupedal runners and walkers.Humphrey N. Keynes R. Skoyles JR. (2006). Hand-walkers : five siblings who never stood up. Discussion Paper.
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Her big toe, for example, spreads out quite a bit from her foot to better grasp tree limbs. Unlike chimpanzees, however, her foot contains a unique small bone inside a tendon which kept the big toe stronger. When seen along with Ardi's other bone structures, this unique bone would have helped her walk bipedally, though less efficient than Lucy. Her wrist bones also provided her with flexibility but the palm bones were short.
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Their mode of transportation is called brachiation, where they swing from branches to get around. They have been documented to swing up to 15 meters in a single leap and as fast as 55 kilometers per hour. Apart from other primates, all gibbons walk bipedally; holding their long arms over their heads. The average life span for a white- bearded gibbon is 25 years and grow anywhere from 17 to 25 inches.
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The Yellow Cat Member of the Cedar Mountain Formation is known for its dinosaurs, including the small coelurosaurian theropod Nedcolbertia, the dromaeosaurid Utahraptor, brachiosaurid sauropod Cedarosaurus, and heavily armored ankylosaurid Gastonia. Whether a basal hadrosaurid or derived non- hadrosaurid iguanodontian, Cedrorestes would have been a large herbivore capable of moving both bipedally or on all fours.Horner, John R.; Weishampel, David B.; and Forster, Catherine A. (2004). "Hadrosauridae". The Dinosauria, 2nd edition. 438–463.
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Galagos are tree dwelling primates and are capable of leaping great distances, using flattened disks on their feet and hands as a way of grasping branches. However they do walk on the ground sometimes, either bipedally or on all fours. Galagos are solitary foragers, however they do meet up at night in groups, and sleep during the day in groups of around 6. Calls are a big part of galago life and there are up to 18 distinct calls.
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One hypothesis for human bipedalism is that it evolved as a result of differentially successful survival from carrying food to share with group members, although there are alternative hypotheses. ; Injured individuals Injured chimpanzees and bonobos have been capable of sustained bipedalism. Three captive primates, one macaque Natasha and two chimps, Oliver and Poko (chimpanzee), were found to move bipedally . Natasha switched to exclusive bipedalism after an illness, while Poko was discovered in captivity in a tall, narrow cage.
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Females must be able to carry out the process of childbirth but also be able to move bipedally. The human female pelvis has evolved to be as wide as possible while still being able to allow bipedal locomotion. The compromise between these two necessary functions of the female pelvis can be especially seen through the comparative skeletal anatomy between males and females. The human pelvis is made up of three sections: the hip bones (ilium, ischium and pubis), the sacrum, and the coccyx.
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Boston: Houghton Mifflin Company. . For this reason, conflicts are most often resolved by displays and other threat behaviours that are intended to intimidate without becoming physical. The ritualized charge display is unique to gorillas. The entire sequence has nine steps: (1) progressively quickening hooting, (2) symbolic feeding, (3) rising bipedally, (4) throwing vegetation, (5) chest-beating with cupped hands, (6) one leg kick, (7) sideways running, two-legged to four-legged, (8) slapping and tearing vegetation, and (9) thumping the ground with palms to end display.
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Gibbons (of the genus Hylobates) are low-speed obligate bipeds when on the ground but travel quadrupedally in other contexts. Because they usually move through trees, their anatomy has become specialized for vertical clinging and leaping, which uses hip and knee joint extensions that are similar to those used in bipedal motion. They also use three back muscles (the multifidus, longissimus thoracis, and iliocostalis lumborum) that are key to bipedal motion in chimpanzees as well as humans. This anatomy necessitates that they move bipedally on the ground.
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Saurolophus (; meaning "lizard crest") is a genus of large saurolophine hadrosaurid dinosaurs that lived about 70.0–66 million years ago, in the Late Cretaceous of North America and Asia; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from the skull. Saurolophus was a herbivorous dinosaur which could move about either bipedally or quadrupedally. The type species, S. osborni, was described by Barnum Brown in 1912 from Canadian fossils.
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On water, basilisks can run at a velocity of per second for approximately before sinking on all fours and swimming. Flaps between their toes help support basilisks, creating a larger surface and pockets of air, giving them the buoyancy needed to run across water. They can also sustain themselves on all fours while "water- walking" to increase the distance travelled above the surface by about . A similar behavior, running bipedally across water, is known from the sailfin lizards and a few species of anole lizards.
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Russell Howard Tuttle (born August 18, 1939) is a distinguished primate morphologist, paleoanthropologist, and a four-field (linguistics, archaeology, sociocultural anthropology and biological anthropology) trained Anthropologist. He is currently an active Professor of Anthropology, Evolutionary Biology, History of Science and Medicine and the College at the University of Chicago. Tuttle was enlisted by Mary Leakey to analyze the 3.4-million-year-old footprints she discovered in Laetoli, Tanzania. He determined that the creatures that left these prints walked bipedally in a fashion almost identical to human beings.
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Hadrosaurids were capable of feeding up to 2 m when standing quadrupedally, and up to 5 m bipedally. Coprolites (fossilized droppings) of some Late Cretaceous hadrosaurs show that the animals sometimes deliberately ate rotting wood. Wood itself is not nutritious, but decomposing wood would have contained fungi, decomposed wood material and detritus-eating invertebrates, all of which would have been nutritious. Examination of hadrosaur coprolites from the Grand Staircase-Escalante indicates that shellfish such as crustaceans were also an important component of the hadrosaur diet.
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Other mammals engage in limited, non- locomotory, bipedalism. A number of other animals, such as rats, raccoons, and beavers will squat on their hindlegs to manipulate some objects but revert to four limbs when moving (the beaver will move bipedally if transporting wood for their dams, as will the raccoon when holding food). Bears will fight in a bipedal stance to use their forelegs as weapons. A number of mammals will adopt a bipedal stance in specific situations such as for feeding or fighting.
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The burrow may be long and up to deep, and the animal can excavate passages at the rate of in ten minutes or so. The species is nocturnal and emerges after dark to forage primarily for seeds, but also eats grasses, shoots, leaves, bulbs, roots and insects. It moves bipedally, normally making hops that are about long, but making great bounds of when agitated. Breeding takes place during the summer with two or three litters, each averaging three or four young, being produced after a gestation period of 25 to 30 days.
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2008, argued that the thick pectoral girdle served for locomotion of the forelimbs. They noted that this does not, however, detract from the theory that Postosuchus could also walk bipedally. In 2013, a major study of the skeletal structure concluded that Postosuchus may have been an obligate biped based on evidence from the anatomy of the digits, vertebrae, and pelvis. The proportions of the limbs and weight-bearing sections of the spine were very similar to many theropod dinosaurs, nearly all of which are thought to have been strictly bipedal.
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These unique adaptations suited their feeding habits of browsing in the case of S. occidentalis, but other species were most likely grazers. The body mass of the largest species is estimated to be , nearly three times that of the largest extant species. Due to their giant height and weight, the largest species possibly did not hop as a form of locomotion, but rather walked bipedally in a similar manner to hominids. This gait would have been used at slow speeds, since hopping at slow speeds would have been inefficient.
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Oliver was acquired as a young animal in 1970 by trainers Frank and Janet Berger. Supposedly, the chimpanzee had been caught in the Congo. Some physical and behavioral evidence led the Bergers to believe Oliver was a creature other than a chimpanzee, perhaps a human-chimp hybrid. Oliver possessed a flatter face than his fellow chimpanzees; was in the habit of walking bipedally, rather than on his knuckles, much more often than his chimpanzee peers (until he was later struck with arthritis); and may have preferred human females over chimpanzee females.
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Chimps may also express themselves with the "pout", which is made in distress, the "sneer", which is made when threatening or fearful, and "compressed-lips face", which is a type of display. When submitting to a dominant individual, a chimp crunches, bobs, and extends a hand. When in an aggressive mode, a chimp swaggers bipedally, hunched over and arms waving, in an attempt to exaggerate its size. While travelling, chimps keep in contact by beating their hands and feet against the trunks of large trees, an act that is known as "drumming".
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Cabarzia is an extinct genus of varanopid from the Early Permian of Germany. It contains only a single species, Cabarzia trostheidei, which is based on a well-preserved skeleton found in red beds of the Goldlauter Formation. Cabarzia shared many similarities with Mesenosaurus romeri (a varanopid from Russia), although it did retain some differences, such as more curved claws, a wide ulnare, and muscle scars on its sacral ribs. With long, slender hindlimbs, a narrow body, an elongated tail, and short, thick forelimbs, Cabarzia was likely capable of running bipedally to escape from predators, a behavior shared by some modern lizards.
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A chimpanzee standing on two legs. Apes in closed forest habitats (habitats enclosed by trees) are considered to be more bipedal than chimpanzees and baboons, both when they are standing stationary or moving bipedally. The proportions of the foot in the gorilla are better adapted to bipedal standing than other primate species. In specific circumstances, such as ground conditions, some ape feet perform better than human feet in terms of bipedal standing, as they have a larger RPL (ratio of the power arm to the load arm) and reduce the muscle force when the foot contacts the ground.
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Many primate and bear species will adopt a bipedal gait in order to reach food or explore their environment, though there are a few cases where they walk on their hind-limbs only. Several arboreal primate species, such as gibbons and indriids, exclusively walk on two legs during the brief periods they spend on the ground. Many animals rear up on their hind legs whilst fighting or copulating. Some animals commonly stand on their hind-legs, in order to reach food, to keep watch, to threaten a competitor or predator, or to pose in courtship, but do not move bipedally.
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These roughened knobs were likely to have been used for inter- and intra-specific interactions. While they would not have been much use as a physical defense against predators, another possible function for these structures would be in pushing or butting contests between members of the same species either for mating rights or social disputes. Auroraceratops is a rather derived moderate-sized basal neoceratopsian that adds diversity to that clade, displaying skull features not present in Archaeoceratops or Liaoceratops. A detailed analysis of the post-cranial skeleton published in 2019 showed that the animal would have walked bipedally and had an estimated body weight of .
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E. annectens in a quadrupedal pose Like other hadrosaurids, Edmontosaurus is thought to have been a facultative biped, meaning that it mostly moved on four legs, but could adopt a bipedal stance when needed. It probably went on all fours when standing still or moving slowly, and switched to using the hind legs alone when moving more rapidly. Research conducted by computer modeling in 2007 suggests that Edmontosaurus could run at high speeds, perhaps up to . Further simulations using a subadult specimen estimated as weighing when alive produced a model that could run or hop bipedally, use a trot, pace, or single foot symmetric quadrupedal gait, or move at a gallop.
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Within mammals, habitual bipedalism has evolved multiple times, with the macropods, kangaroo rats and mice, springhare, hopping mice, pangolins and hominin apes (australopithecines and humans) as well as various other extinct groups evolving the trait independently. In the Triassic period some groups of archosaurs (a group that includes crocodiles and dinosaurs) developed bipedalism; among the dinosaurs, all the early forms and many later groups were habitual or exclusive bipeds; the birds are members of a clade of exclusively bipedal dinosaurs, the theropods. A larger number of modern species intermittently or briefly use a bipedal gait. Several lizard species move bipedally when running, usually to escape from threats.
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In 1908, these two specimens were mounted side-by-side in the American Museum of Natural History, under the name Trachodon mirabilis. Cope's specimen is positioned on all fours with its head down, as if feeding, because it has the better skull, while Brown's specimen, with a less perfect skull, is posed bipedally with the head less accessible. Henry Fairfield Osborn described the tableau as representing the two animals feeding along a marsh, the standing individual having been startled by the approach of a Tyrannosaurus. Impressions of appropriate plant remains and shells based on associated fossils were included on the base of the group, including ginkgo leaves, Sequoia cones, and horsetail rushes.
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They have curved claws on their forelimbs and soft pads on their hind limbs that aid in their climbing ability, and they have some independent movement of their digits as well as good dexterity due to their forelimbs being able to bend a great deal. The 4th and 5th digit of their feet are enlarged, the 1st digit is absent, and the 2nd and 3rd digits are syndactylous (two digits that look like one fused together). Scientists have discovered that the Matschie's are able to walk bipedally and there's a lot of rotation in their limbs for climbing. Out of all of the Dendrolagus species, the Matschie's tree-kangaroo is the best vertical climber and has more strength in its muscles than any others.
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The convenience of the savanna-based theory caused this point to be overlooked for over a hundred years.Shreeve, James, "Sunset on the savanna" , ‘’Discover, 1996 Some of the fossils found actually showed that there was still an adaptation to arboreal life. For example, Lucy, the famous Australopithecus afarensis, found in Hadar in Ethiopia, which may have been forested at the time of Lucy's death, had curved fingers that would still give her the ability to grasp tree branches, but she walked bipedally. “Little Foot,” a nearly-complete specimen of Australopithecus africanus, has a divergent big toe as well as the ankle strength to walk upright. “Little Foot” could grasp things using his feet like an ape, perhaps tree branches, and he was bipedal.
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The researchers found to their surprise that the fastest gait was kangaroo-like hopping (maximum simulated speed of ), which they regarded as unlikely based on the size of the animal and lack of hopping footprints in the fossil record, and instead interpreted the result as indicative of an inaccuracy in their simulation. The fastest non-hopping gaits were galloping (maximum simulated speed of ) and running bipedally (maximum simulated speed of ). They found weak support for bipedal running as the most likely option for high-speed movement, but did not rule out high-speed quadrupedal movement. While long thought to have been aquatic or semiaquatic, hadrosaurids were not as well-suited for swimming as other dinosaurs (particularly theropods, who were once thought to have been unable to pursue hadrosaurids into water).
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In the 1980s, paleontologist Kevin Padian suggested that smaller pterosaurs with longer hindlimbs, such as Dimorphodon, might have walked or even ran bipedally, in addition to flying, like road runners. However, a large number of pterosaur trackways were later found with a distinctive four-toed hind foot and three-toed front foot; these are the unmistakable prints of pterosaurs walking on all fours. Fossil footprints show that pterosaurs stood with the entire foot in contact with the ground (plantigrade), in a manner similar to many mammals like humans and bears. Footprints from azhdarchids and several unidentified species show that pterosaurs walked with an erect posture with their four limbs held almost vertically beneath the body, an energy-efficient stance used by most modern birds and mammals, rather than the sprawled limbs of modern reptiles.
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Norman stated in 1985 the possibility Segnosaurus was an aquatic fish-eater could explain its small, pointed teeth and broad and perhaps webbed feet, but found it mysterious why it should have a horny beak. Restoration showing large area behind the legs caused by the backwards directed pubic bone; therizinosaurs may have "sat" on their pelvises during feeding In 1993, Russell and Dong considered the small size of the head, blunt beaks and large body weights of therizinosaurs consistent with herbivory. In 1993 and 1997, Russell suggested therizinosaurs would have "sat" on their pelvises and supported their bodies on their hind limbs while using their long arms, claws, and flexible necks to reach leaves from trees and bushes with their beaks. They could have reached even higher while standing and browsing bipedally.
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Conversely, when suddenly forced to share their habitat with an efficient anole predator like the northern curly-tailed lizard (for example, if it is introduced to a place where formerly not present), the anoles may decrease the amplitude of their head bobbing, making them less conspicuous, and may become slower to emerge from hiding (less willing to take a risk) after having been scared by a predator. Slow-moving anoles, like the twig ecomorphs of the Caribbean and many Dactyloa species of mainland Central and South America, are generally cryptically colored and often coordinate their movements with the wind, resembling the surrounding vegetation. A few semi- aquatic species will attempt to escape from predators by diving into water or running bipedally across it, similar to basilisks. However, the anoles lack the specialized toe fringes that helps basilisks when doing this.
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The non-human apes (the gibbons, mountain and lowland gorillas, orangutans, chimpanzees and bonobo) tend to walk on the lateral side of the foot, that is with an 'inverted' foot, which may reflect a basic adaptation to walking on branches. It is often held that their feet lack longitudinal arches, but footprints made by bipedally walking apes, which must directly or indirectly reflect the pressure they exert to support and propel themselves do suggest that they exert lower foot pressure under the medial part of their midfoot. However, human feet, and the human medial longitudinal arch, differ in that the anterior part of the foot is medially twisted on the posterior part of the foot, so that all the toes may contact the ground at the same time, and the twisting is so marked that the most medial toe, the big toe or hallux, (in some individuals the second toe) tends to exert the greatest propulsive force in walking and running. This gives the human foot an 'everted' or relatively outward-facing appearance compared to that of other apes.
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