Carnassials of a Eurasian wolf Many carnivorous mammals have enlarged and blade-like teeth especially adapted for slicing and chopping called carnassials. A general term for such blade-like teeth is secodont or plagiaulacoid.
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Among the hyaenodontids, it is M2 and m3. Unlike most modern carnivorans, in which the carnassials are the sole shearing teeth, other creodont molars have a subordinate shearing functions. The difference in which teeth form the carnassials is a major argument for the polyphyly of Creodonta.
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Carnassials of a dog Carnassials are paired upper and lower teeth (either molars or premolars and molars) modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. The modification arose separately in several groups of carnivorous mammals. Different pairs of teeth were involved in the separate modifications. In modern Carnivora, the carnassials are the modified fourth upper premolar and the first lower molar.
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With sharp canines and slicing carnassials, Cladosictis's teeth were similar to those of carnivorans, although the groups were unrelated.
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In the order Carnivora, either the molars, or the premolars and molars in combination, may be adapted into shearing carnassials.
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The distribution of fractures across the tooth row also differs, with Beringian wolves having much higher frequencies of fracture for incisors, carnassials, and molars. A similar pattern was observed in spotted hyenas, suggesting that increased incisor and carnassial fracture reflects habitual bone consumption because bones are gnawed with the incisors and then cracked with the carnassials and molars.
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The carnassials are usually formed by the fourth upper premolar and the first lower molar, working one against the other with a scissorlike action.
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Creodonts have two or three pairs of carnassial teeth, but only one pair performed the cutting function (either M1/m2 or M2/m3). This arrangement is unlike modern carnivorans, which use P4 and m1 for carnassials, and this suggests a separate evolutionary history and an order-level distinction. Different molars were involved in the two major groups of creodonts. In the Oxyaenidae, it is M1 and m2 that form the carnassials.
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Striped hyena skull. Note the disproportionately large carnassials and premolars adapted for bone consumption Aardwolf skull. Note the greatly reduced molars and carnassials, rendered redundant from insectivory Hyenas have relatively short torsos and are fairly massive and wolf-like in build, but have lower hind quarters, high withers and their backs slope noticeably downward toward their rumps. The forelegs are high, while the hind legs are very short and their necks are thick and short.
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It has 35–40 teeth, with highly developed carnassials, used for shearing meat. It weighs . Sexually dimorphic Egyptian mongooses were observed in Portugal, where some females are smaller than males.
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While not all mustelids share an identical dentition, they all possess teeth adapted for eating flesh, including the presence of shearing carnassials. With variation between species, the most common dental formula is .
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Grohé et al. 2012 order of carnivorous mammals that lived from the Paleocene to the Miocene epochs. Because they both possess carnassial teeth, creodonts and carnivorans were once thought to have shared a common ancestor, but given that different teeth are involved in making up the carnassials (both between creodonts and carnivorans and between the main groups of creodonts), this appears to be a case of evolutionary convergence. Carnassials are also known in other mammal clades, such as in the extinct bat Necromantis.
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The long, curved canines have a sharp ridge on the posterior surface, and the outer incisors are canine-like. Its carnassials are smaller than those of the more carnivorous black-backed jackal. Females have four inguinal teats.
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The creodont lumbosacral spine was not arranged as efficiently for running as in Carnivora. The arrangement of the teeth was also somewhat different. In the miacids (as with the modern Carnivora), the last upper premolar and the first lower molar are the carnassials, allowing grinding teeth to be retained behind for feeding on non- meat foods (the Canidae are the closest modern analog to miacid dentition). In creodonts, the carnassials were further back—either the first upper and second lower molars, or the second upper and third lower molars.
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Sinopa grangeri Because of their size range, it is probable that different species hunted in different ways, which allowed them to fill many different predatory niches. Smaller ones would hunt in packs during the night like wolves, and bigger, fiercer ones would hunt alone during the daylight, using their sheer size and their mighty jaws as their principal weapon. The carnassials in a hyaenodontid are generally the second upper and third lower molars. However, some hyaenodontids possessed as many as three sequential pairs of carnassials or carnassial-like molar teeth in their jaws.
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Various evolutionary modifications have occurred, such as the lack of canines in Glires, the development of tusks from either incisors (elephants) or canines (pigs and walruses), the adaptation of molars into flesh-shearing carnassials in Carnivora, and others.
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Like most deltatheroideans, Tsagandelta was a carnivore, its molar anatomy similar to the carnassials of other carnivorous therians. Tsagandelta and its relatives (as well as the unrelated eutriconodonts) are among the Mesozoic mammals most clearly specialised to meat-eating.
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M1 and m2 form the carnassials, while M3/m3 are absent. The manus and pes are plantigrade or subplantigrade. The fibula articulates with the calcaneum, and the astragalus articulates with the cuboid bone. The phalanges are compressed and fissured at the tip.
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Likewise, Gunnell's list of defining features of hyaenodontids includes: Long, narrow skull with a narrow basicranium and a high narrow occiput. The frontal bones are concave between the orbital regions. M2 and m3 form the carnassials. M3 is present in most species, while m3 is always present.
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The snout width was greater than those of both the Pleistocene and modern wolves, and implies well-developed carnassials driven by powerful jaws. In two morphometric analyses, the nearest dog skull- shape that was similar to the Paleolithic dog was that of the Central Asian Shepherd Dog.
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In The Wolves of North America Part 2. Young, S. P. & Goldman, E. A. (Eds.) New York: Dover Publs. p. 430. and larger carnassials. Since 1930, there has been a progressive reduction in size in Arctic wolf skulls, which is likely the result of wolf-dog hybridization.
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New York: Columbia University Press. pp. 216–248. . Terrestrial or aquatic, Astroconodon, like most eutriconodonts, was almost certainly a predator. Like in most eutriconodonts, its triconodont molars were adapted for shearing, much ike the carnassials of therian carnivores.Zofia Kielan- Jaworowska, Richard L. Cifelli, Zhe-Xi Luo (2004).
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Dentition of tiger above, and of Asian black bear below. The large canines are used for killing, and the carnassials for tearing flesh. Tigers are thought to be mainly nocturnal predators, but in areas where humans are absent, remote-controlled, hidden camera traps recorded them hunting in daylight.BBC (2008).
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In comparison to extant North American gray wolves, Beringian wolves included many more individuals with moderately to heavily worn teeth and with a significantly greater number of broken teeth. The frequencies of fracture in wolves ranged from a minimum of 2% found in the Northern Rocky Mountain wolf (Canis lupus irremotus) up to a maximum of 11% found in Beringian wolves. The distribution of fractures across the tooth row also differs, with Beringian wolves having much higher frequencies of fracture for incisors, carnassials, and molars. A similar pattern was observed in spotted hyenas, suggesting that increased incisor and carnassial fracture reflects habitual bone consumption because bones are gnawed with the incisors and then cracked with the carnassials and molars.
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The spotted hyena also has its carnassials situated behind its bone-crushing premolars, the position of which allows it to crush bone with its premolars without blunting the carnassials. Combined with large jaw muscles and a special vaulting to protect the skull against large forces, these characteristics give the spotted hyena a powerful bite which can exert a pressure of 80 kgf/cm2 (1140 lbf/in²), which is 40% more force than a leopard can generate.Hunter, Luke & Hinde, Gerald (2005) Cats of Africa, Struik, The jaws of the spotted hyena outmatch those of the brown bear in bonecrushing ability,Savage, R. J. G. (1955) Giant deer from Lough Beg. The Irish Naturalists’ Journal 11d: 1–6.
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Some species were arboreal, while others lived on the ground. They probably fed on invertebrates, lizards, birds, and smaller mammals like shrews and opossums. Their teeth and skulls show that the miacids were less developed than modern carnivorans. They had carnivoran-type carnassials, but lacked fully ossified auditory bullae (rounded protrusions).
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Most mustelids, including otters, have specialized teeth, including sharp canines and carnassials that inflict lethal bites to prey. Also, North American river otters have large molars used for crushing hard objects, such as the shells of molluscs. An adult North American river otter has a total of 36 teeth. Additional premolars may be present.
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Its tapering tail is about half the length of the head and body. Its skull is short and round with a basal length of and a width of . The ear canal and the openings of the ears are larger than in most Felis species. The cheek teeth are long and the upper carnassials long.
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The canine teeth measure 14–22 mm in length, while the carnassials are relatively small. The Ethiopian wolf has eight mammae, of which only six are functional. The front paws have five toes, including a dewclaw, while the hind paws have four. As is typical in the genus Canis, males are larger than females, having 20% greater body mass.
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Their incisors are small and chisel-shaped, their canine teeth are prominent and their carnassials are not overly specialized. Their molars are flattened and adapted for grinding. Their jaws are powerful enough to crush most bones; a provoked badger was once reported as biting down on a man's wrist so severely that his hand had to be amputated. The dental formula is .
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Sand cat specimens collected in the Karakum Desert in Turkestan were described as darker and greyer in fur colour than the Saharan sand cat (F. m. margarita), with less pronounced markings and only 2–3 tail rings. Specimens from Pakistan were more strongly marked, had shorter carnassials and a less expanded occiput than ones from Turkestan. Later studies confirmed that F. m.
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Reflecting their omnivorous diets, raccoon dogs have small and weak canines and carnassials, flat molars, and relatively long intestines – (1.5–2.0 times longer than other canids). They have long torsos and short legs. Total lengths can range from . The tail, at long, is short, amounting to less than a third of the animal's total length and hangs below the tarsal joints without touching the ground.
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Around 9–10 mya during the Late Miocene, the Canis, Urocyon, and Vulpes genera expanded from southwestern North America, where the canine radiation began. The success of these canines was related to the development of lower carnassials that were capable of both mastication and shearing. Around 8 Mya, the Beringian land bridge allowed members of the genus Eucyon a means to enter Asia and they continued on to colonize Europe.
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On the lower carnassials (first lower molars), the talonid has evolved to become a cutting blade for flesh-slicing, with a reduction or loss of the post-carnassial molars. This adaptation also occurs in two other hypercarnivores – the dhole and the bush dog. The African wild dog exhibits one of the most varied coat colours among the mammals. Individuals differ in patterns and colours, indicating a diversity of the underlying genes.
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While not all share identical dentition, they all possess teeth adapted for eating flesh, including the presence of shearing carnassials. Members of Family Procyonidae (raccoons, coatis) are smallish animals, with generally slender bodies and long tails. Nineteen extant species in six genera are currently recognized. Except for the kinkajou, all procyonids have banded tails and distinct facial markings, and like bears, are plantigrade, walking on the soles of their feet.
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The mane is erectile and typically is used to enlarge the wolf's profile when threatened or when displaying aggression. Melanistic maned wolves do exist, but are rare. The first photograph of a black adult maned wolf was taken by a camera trap in northern Minas Gerais in Brazil in 2013. Skull of a maned wolf The skull can be identified by its reduced carnassials, small upper incisors and long canine teeth.
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Dentition Mesocarnivore cheek teeth are heterodont and their different shapes reflect distinct functions. Incisors and canines are used to apprehend food and kill prey, pointed premolars pierce and hold prey, and molars are involved in both slicing and crushing functions. The slicing function of the molars is produced by occlusion between the carnassials, the lower first molar, and the upper fourth premolar. Mesocarnivores are first represented by the Miacidae.
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Most proborhyaenids had a robust, hyena-like skull, although one species, Callistoe vincei, had an elongate, narrow skull more reminiscent of a thylacine. The teeth were strongly specialized as carnassials for eating meat, and in Arminiheringia rotated throughout the animal's life to maintain a continuous shearing blade on the tooth. Preserved specimens of their canines lack enamel;Marshall, L. Evolution of the Borhyaenidae, extinct South American predaceous marsupials. Berkeley: University of California Press, 1978.
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The specific epithet pictus (Latin for "painted"), which derived from the original picta, was later returned to it, in conformity with the International Rules on Taxonomic Nomenclature.Bothma, J. du P. & Walker, C. (1999). Larger Carnivores of the African Savannas, Springer, pp. 130–157, Paleontologist George G. Simpson placed the African wild dog, the Dhole, and the Bush dog together in the subfamily Simocyoninae on the basis of all three species having similarly trenchant carnassials.
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However, its skull lacks the vaulted forehead of hyenas and other specialized bone-eating durophagous mammals, indicating that its diet was perhaps a mixture of hard foodstuffs (e.g. snails, bones) alongside small vertebrates and carrion; although omnivorous habits were suggested in the past, it appears that it was incapable of processing plant matter, rendering it more likely to be hypercarnivorous or durophagous. Some convergence with the carnassials of other predatory mammal groups has also been noted.
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Ichthyoconodon and Dyskritodon amazighi are the only Mesozoic mammals so far to have been suggested to have possibly foraged in the sea. Researchers such as Zofia Kielan-Jaworowska pointed out lack of functional comparison between eutriconodont teeth and those of marine mammals. Unlike the teeth of seals and cetaceans, eutriconodont molars occlude, creating a shearing motion like carnassials, and unlike the grasping function of marine mammal molars.Zofia Kielan-Jaworowska, Richard L. Cifelli, Zhe-Xi Luo (2004).
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This aardwolf skull exhibits greatly reduced molars and carnassials teeth as they are unnecessary for any large, insectivorous animal subsisting on soft insects such as termites. The dentition of a shrew is very different. The aardwolf uses its canine teeth in self-defence and, occasionally, in digging; accordingly, the canines have not been greatly reduced. robber fly eating a hoverfly The giant anteater, a large insectivorous mammal An insectivore is a carnivorous plant or animal that eats insects.
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In cats, the incisors are small; biting off meat is done with the canines and the carnassials. In elephants, the upper incisors are modified into curved tusks (unlike with Narwhals, where it is a canine that develops into a straight and twisted tusk). The incisors of rodents grow throughout life and are worn by gnawing. In humans, the incisors serve to cut off pieces of food, as well as in the grip of other food items.
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Also, unlike other hyenas, the female spotted hyena's external genitalia closely resembles that of the male. Their dentition is similar to that of the canid, but is more specialised for consuming coarse food and crushing bones. The carnassials, especially the upper, are very powerful and are shifted far back to the point of exertion of peak pressure on the jaws. The other teeth, save for the underdeveloped upper molars, are powerful, with broad bases and cutting edges.
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The species likely evolved from the Chinese Meles thorali of the early Pleistocene. The modern species originated during the early Middle Pleistocene, with fossil sites occurring in Episcopia, Grombasek, Süssenborn, Hundsheim, Erpfingen, Koneprusy, Mosbach 2, and Stránská Skála. A comparison between fossil and living specimens shows a marked progressive adaptation to omnivory, namely in the increase in the molars' surface areas and the modification of the carnassials. Occasionally, badger bones are discovered in earlier strata, due to the burrowing habits of the species.
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The Javan tiger was small compared to other subspecies of the Asian mainland, but larger than the Bali tiger, and similar in size to the Sumatran tiger. It usually had long and thin stripes, which were slightly more numerous than those of the Sumatran tiger. Its nose was long and narrow, occipital plane remarkably narrow and carnassials relatively long. Based on these cranial differences, the Javan tiger was proposed to be assigned to a distinct species, with the taxonomic name Panthera sondaica.
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E. emlongi and Macrodelphinus (background) It had a short tail and developed limbs with webbed feet. Unlike modern sea lions, it had a set of slicing carnassials; the presence of slicing teeth (rather than purely piercing teeth as in modern fish-eating pinnipeds) suggests that Enaliarctos needed to return to shore with prey items in order to masticate and ingest them. Still, Enaliarctos had some sea lion-like characteristics, such as large eyes, sensitive whiskers, and a specialized inner ear for hearing underwater.
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In 1905, the German zoologist Max Hilzheimer first described the South China tiger as similar in height to the Bengal tiger but differing in skull and coat characteristics. Their carnassials and molars are shorter than in the Bengal tiger samples; the cranial region is shorter with orbits set closer together, postorbital processes are larger. Their coat is lighter and more yellowish and the paws, face, and stomach appear more white; the stripes are narrower, more numerous and more sharp-edged.Hilzheimer, M. (1905).
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Diagram of a wolf skull with key features labelled Merriam named 3 unusual species based on specimens recovered from the Rancho La Brea tar pits. They were regarded by Nowak as taxonomic synonyms for Canis lupus. Canis occidentalis furlongi (Merriam 1910) was described as a wolf considerably smaller than the dire wolf and more closely related to the timber wolf Canis lupus occidentalis. However, its premolar P4 (upper carnassials) were massive, and the hypocone of the molar M1 was larger than that of the dire wolf.
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These "wolves on hooves" were probably one of the more important predator groups in the late Paleocene and Eocene ecosystems of Europe (which was an archipelago at the time), Asia (which was an island continent), and North America. Mesonychid dentition consisted of molars modified to generate vertical shear, thin blade- like lower molars, and carnassial notches, but no true carnassials. The molars were laterally compressed and often blunt, and were probably used for shearing meat or crushing bones. The largest species are considered to have been scavengers.
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They are grouped into three categories: mesocarnivory (50–70% meat), hypercarnivory (70% and greater of meat), and hypocarnivory (50% or less of meat). The dentition of hypocarnivores consists of dull, triangular carnassial teeth meant for grinding food. Hypercarnivores, however, have conical teeth and sharp carnassials meant for slashing, and in some cases strong jaws for bone- crushing, as in the case of hyenas, allowing them to consume bones; some extinct groups, notably the Machairodontinae, had saber-shaped canines. Some physiological carnivores consume plant matter and some physiological herbivores consume meat.
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Early creodonts (both oxyaenids and hyaenodontids) displayed the tribosphenic molars common for basal therians. Small forms had somewhat strong postmetacrista-metastellar crests suggesting that they were probably opportunistic feeders, eating such things as eggs, birds, small mammals, insects and possibly plant matter as well, possibly like extant viverrids. Larger forms had greater shearing capacity and the capacity increased over time. Arfia, one of the most common carnivorous mammals in early Eocene North America, developed a more open trigonid on M3 over the course of the Early Eocene, increasing the shearing ability of the carnassials.
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The cheetah has a total of 30 teeth; the dental formula is . The sharp, narrow carnassials are larger than those of leopards and lions, suggesting the cheetah can consume larger amount of food in a given time period. The small, flat canines are used to bite the throat and suffocate the prey. A study gave the bite force quotient (BFQ) of the cheetah as 119, close to that for the lion (112), suggesting that adaptations for a lighter skull may not have reduced the power of the cheetah's bite.
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Location of a dog's carnassials; the inside of the 4th upper premolar aligns with the outside of the 1st lower molar, working like scissor blades Isotopic bone collagen analysis of the specimens indicated that they ate horse, bison, woodland muskox, and mammoth — i.e., Pleistocene megafauna. This supports the conclusion that they were capable of killing and dismembering large prey. Compared with Pleistocene and extant gray wolves, the megafaunal wolf was hypercarnivorous, with a craniodental morphology more capable of capturing, dismembering, and consuming the bones of very large mega-herbivores.
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The anterior and posterior cusps are reduced and the central cusp enlarged and widened, so that the tooth is converted from a blade-like structure to a heavy conical hammer. Strong muscles are also required for bone crushing, and the temporalis attachment on the skull is enlarged by a strong sagittal crest. Heavy, hammer-like teeth and extremely strong jaws and jaw muscles make it possible for hyaenas to crack larger bone than other carnivores are capable of, and their highly efficient cutting carnassials can deal with tough hides and tendons.
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A comparison of the size and shape of carnassial teeth in: [A] bear (Ursus), [B] leopard (Panthera), [C] dog (Canis), [D] badger (Meles), [E] otter (Lutra), [F] raccoon (Procyon), [G] mongoose (Herpestes), [H] weasel (Mustela). Photo taken at Imperial College London. The fossil record indicates the presence of carnassial teeth 50 million years ago, implying that Carnivora family members descend from a common ancestor. The shape and size of sectorial teeth of different carnivorous animals vary depending on diet, illustrated by the comparisons of bear (Ursus) carnassials with those of a leopard (Panthera).
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Bears, being omnivores, have a flattened, more blunt carnassial pair than leopards. This reflects the bear's diet, as the flattened carnassials are useful both in slicing meat and grinding up vegetation, whereas the leopard's sharp carnassial pairs are more adapted for its hypercarnivorous diet. During the Late Pleistocene – early Holocene a now extinct hypercarnivorous wolf ecomorph existed that was similar in size to a large extant gray wolf but with a shorter, broader palate and with large carnassial teeth relative to its overall skull size. This adaptation allowed the megafaunal wolf to predate and scavenge on Pleistocene megafauna.
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The load per 1 cm2 of the supporting surface of the beech marten's foot (30.9 g) is double that of the pine marten (15.2 g), thus it is obliged to avoid snowy regions. Its skull is similar to that of the pine marten, but differs in its shorter facial region, more convex profile, its larger carnassials and smaller molars. The beech marten's penis is larger than the pine marten's, with the bacula of young beech martens often outsizing those of old pine martens. Males measure 430–590 mm in body length, while females measure 380–470 mm.
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Front limb There was marked sexual dimorphism in A. giganteus, with males being much larger than females. The species Amphimachairodus coloradensis, from the United States (formerly Machairodus coloradensis) was a significantly large animal, about at the shoulder, according to skeletal and life reconstructions, potentially making it one of the largest known felids. All Amphimachairodus species have a developed mandibular flange, however, A. colaradensis is distinguishable from A. giganteus and A. kurteni by subtle differences in the shape of the mandible and placement of lower carnassials. In size and proportions, the Eurasian species A. giganteus was remarkably similar to a modern lion or tiger and had a shoulder height of .
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The auditory bullae are inflated in form, and the sagittal crest is weakly developed. The dentition—40 teeth with the dental formula:—is adapted to their omnivorous diet: the carnassials are not as sharp and pointed as those of a full-time carnivore, but the molars are not as wide as those of a herbivore. The penis bone of males is about long and strongly bent at the front end, and its shape can be used to distinguish juvenile males from mature males. Seven of the thirteen identified vocal calls are used in communication between the mother and her kits, one of these being the birdlike twittering of newborns.
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Williston noticed that, over evolutionary time, the modular and serially repeated parts distinguishing animal groups exhibited trends in numbers and types. For instance, ancient vertebrates were characterized by mouths that contained mostly similar teeth, whereas recent vertebrates are characterized by mouths with different kinds of teeth, adapted for biting, tearing, and compacting food; differences ultimately characterized different diets, with carnivores bearing incisors, canines and carnassials, and grazers bearing mostly molars. In 1914, Williston declared that "it is also a law in evolution that the parts in an organism tend toward reduction in number, with the fewer parts greatly specialized in function". However, empirical studies have not always confirmed this generalization.
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Ancestral spotted hyenas probably developed social behaviours in response to increased pressure from rivals on carcasses, thus forcing them to operate in teams. Spotted hyenas evolved sharp carnassials behind their crushing premolars, therefore they did not need to wait for their prey to die, and thus became pack hunters as well as scavengers. They began forming increasingly larger territories, necessitated by the fact that their prey was often migratory, and long chases in a small territory would have caused them to encroach into another clan's turf. Spotted hyenas spread from their original homeland during the Middle Pleistocene, and quickly colonised a very wide area from Europe, to southern Africa and China.
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The top and bottom carnassials worked together like shears and would have been very effective at slicing off chunks of flesh from carcasses and cutting through bone. Front view of the skull The jaw muscle of the marsupial lion was exceptionally large for its size, giving it an extremely powerful bite. Biometric calculations show, considering size, it had the strongest bite of any known mammal, living or extinct; a individual would have had a bite comparable to that of a African lion. A comparative study of bite force in relation to the body mass of fossil and modern species, found the greatest relative force exerted by the jaws would have been this species and Priscileo roskellyae.
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They suggest that to add nutrients to its diet, Megatherium may have taken over the kills of Smilodon. Based on the estimated strength and mechanical advantage of its biceps, it has been proposed that Megatherium could have overturned adult glyptodonts (large, armored xenarthrans, related to armadillos) as a means of scavenging or hunting these animals. However, noting that sloths lack the carnassials typical of predators and that traces of bone are absent from the many preserved deposits of sloth dung, Paul Martin has described this proposal as "fanciful". Carbon isotope analysis has found that Megatherium has isotope values similar to other megafaunal herbivores such as mammoths, glyptodonts, and Macrauchenia, and significantly unlike omnivorous and carnivorous mammals, suggesting that Megatherium was an obligate herbivore.
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Using 3D modeling based on X-ray computed tomography scans, marsupial lions were found to be unable to use the prolonged, suffocating bite typical of living big cats. They instead had an extremely efficient and unique bite; the incisors would have been used to stab at and pierce the flesh of their prey while the more specialised carnassials crushed the windpipe, severed the spinal cord, and lacerated the major blood vessels such as the carotid artery and jugular vein. Compared to an African lion which may take 15 minutes to kill a large catch, the marsupial lion could kill a large animal in less than a minute. The skull was so specialized for big game that it was very inefficient at catching smaller animals, which possibly contributed to its extinction.
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As the food of modern cats enters the mouth through the side while cutting with the carnassials, not the front incisors between the canines, the animals do not need to gape widely, so the canines of Smilodon would likewise not have been a hindrance when feeding. La Brea S. fatalis skull cast with jaws at maximum gape Despite being more powerfully built than other large cats, Smilodon had a weaker bite. Modern big cats have more pronounced zygomatic arches, while these were smaller in Smilodon, which restricted the thickness and therefore power of the temporalis muscles and thus reduced Smilodons bite force. Analysis of its narrow jaws indicates that it could produce a bite only a third as strong as that of a lion (the bite force quotient measured for the lion is 112).
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At one point in their evolution, spotted hyenas developed sharp carnassials behind their crushing premolars; this rendered waiting for their prey to die no longer a necessity, as is the case for brown and striped hyenas, and thus became pack hunters as well as scavengers. They began forming increasingly larger territories, necessitated by the fact that their prey was often migratory, and long chases in a small territory would have caused them to encroach into another clan's land. It has been theorised that female dominance in spotted hyena clans could be an adaptation in order to successfully compete with males on kills, and thus ensure that enough milk is produced for their cubs. Another theory is that it is an adaptation to the length of time it takes for cubs to develop their massive skulls and jaws, thus necessitating greater attention and dominating behaviours from females.
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