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Smilodon /ˈsmaɪlədɒn/, is an extinct genus of machairodont felid. It is perhaps the best known saber-toothed cat and lived in North America during the Pleistocene epoch (2.5 mya–10,000 years ago). Several fossils have been found, with one of the largest collections taken from the La Brea Tar Pits. Three species of the genus are known; they vary in size and build.

Overall, Smilodon was more robustly built than any modern cat, with particularly well-developed forelimbs and exceptionally long upper canines. Its jaw had a bigger gape than modern cats and its upper canines were slender and fragile, being adapted for precision killing. These attributes made Smilodon a specialized hunter of large herbivores, such as bison and camels.

Smilodon likely lived in closed habitats, such as forests and bush, which would have provided cover for ambushing prey. Its reliance on large animals may have been the cause of its extinction. Scientists debate over whether Smilodon was a social animal. Comparison of predator responses to distress calls and the prevalence of healed injuries suggest that it was social, while its small brain size and vegetated habitat suggest it was more solitary. Some fossils show signs of ankylosing spondylitis, trauma and arthritis. Smilodon went extinct 10,000 years ago.

Commonly referred to as a saber-toothed tiger, they are by no means related to modern tigers or other pantherines, as they belongs to a distinct subfamily.

Etymology[]

The nickname "saber-tooth" refers to the extreme length of their maxillary canines. Despite the colloquial name "saber-toothed tiger", Smilodon is not closely related to the tiger (or any other living felid); the latter belongs to the subfamily Pantherinae, whereas Smilodon belongs to the subfamily Machairodontinae. The name Smilodon comes from Greek: σμίλη, (smilē), "carving knife" + ὀδoύς (odoús), "tooth" (whose stem is odont-, as seen in the genitive case form ὀδόντος, odóntos).

Classification[]

Smilodon gracilis skull ANSP 44

Partial skull of S. gracilis, the earliest species in the genus, Academy of Natural Sciences of Philadelphia

Smilodon californicus mount

S. fatalis skeleton at National Museum of Natural History

Säbelzahnkatze, Tierpark Berlin, 500-606

S. populator statue in Tierpark Berlin

The genus Smilodon was named and described by the Danish naturalist and paleontologist Peter Wilhelm Lund in 1842. He found the fossils of Smilodon populator in caves near the small town of Lagoa Santa, in Minas Gerais, Brazil. It is grouped with several species of saber-toothed cats in the subfamily Machairodontinae within the family Felidae. An early ancient DNA analysis suggested that Smilodon should be grouped with modern cats (subfamily Felinae) However, a 2005 study found that Smilodon belonged to a separate lineage. Another study published a year later confirmed this, showing that the Machairodontinae diverged early from the ancestors of modern cats and were not closely related to any living feline species. The skull and mandible morphology of the earliest saber-toothed cats were similar to that of clouded leopards. The lineage further adapted to the precision killing of large animals by developing elongated canine teeth and wider gapes, in the process sacrificing high bite force. Smilodon belongs to the tribe Smilodontini, which is known as "dirk-toothed cats". These cats were defined by their long slender canines with fine serrations.

Species[]

While a number of Smilodon species have been described, today usually only three are recognized.

  • Smilodon gracilis, 2.5 million–500,000 years ago; the smallest and earliest species, estimated at 55 to 100 kg (120 to 220 lb) in weight[10] was the successor of Megantereon in North America, from which it probably evolved. This species reached the north of South America in the early Pleistocene, along with Homotherium, as part of the Great American Interchange. The other Smilodon species probably derived from this species. As its specific name suggests, this species is the most lightly built of the genus.
  • Smilodon fatalis, 1.6 million–10,000 years ago, replaced S. gracilis in North America and invaded western South America. It was intermediate in size between S. gracilis and S. populator. It ranged from 160 to 280 kg (350 to 620 lb). and reached a shoulder height of 100 cm (39 in) and body length of 175 cm (69 in). Sometimes two additional species are recognized, S. californicus and S. floridanus, but usually they are considered to be junior synonyms of S. fatalis.
  • Smilodon populator, 1 million–10,000 years ago; occurred in the eastern parts of South America and was larger than the North American species. It is perhaps the largest known felid, with a body mass range of 220 to 400 kg (490 to 880 lb). It stood at a shoulder height of 120 cm (47 in). Compared to S. fatalis, S. populator had a more elongated and narrow skull, higher positioned nasals, more massive metapodials and slightly longer forelimbs relative to hindlimbs.

Description[]

Wiki Smilodon Size

Size of the three Smilodon species compared to a human

Smilodon species where the heaviest-built of all machairodontine cats. Smilodon populator in particular was the heaviest, at 800 lbs or more. Its only rivals in size amongst the machairodonts were Amphimachairodus and Machairodus horribilis.

Smilodon fatalis was around the same length as a lion, but slightly heavier at around 430-600 lbs. Smilodon gracilis meanwhile, was the smallest species, estimated to be about the same weight as a jaguar, maxing out at 360 lbs in weight. Its also said to be the ancestor of S. fatalis and S. populator.

Anatomy and Paleobiology[]

Smilodon populator was the largest sabre-toothed cat (popularly known as the sabre tooth tiger). S. populator was a fierce predator about 3 metres long and 1.05 metres tall. Smilodon species weighed anywhere from 110 (gracilis)–400(populator) kg. Smilodon was a bit larger than a modern-day lion (Panthera leo), and much heavier. Smilodon had relatively short, muscular legs and a short, bobbed tail a bit like that of a modern day bobcat.

Lund's Smilodon populator

S. populator skull and canine from Lund's collection, from Zoological Museum, Copenhagen.

Smilodon's front legs were especially powerful and its body was adapted for springing onto prey, but it was not a very fast runner and could not adapt to chase after fast-running prey like deer. Instead, it hunted relatively slower animals such as Macrauchenia, Toxodon, some species of mammoths and mastodon, and ground sloths. Its 31 cm skull had 2 huge sabre-like canine teeth and these were serrated and oval in cross-section. Many Smilodon fossils have been found with broken canines; a fossil wolf was found with a Smilodon tooth fragment embedded in its skull, as well as a Smilodon recovered from the La Brea Tar Pits with a fatal puncture wound from another of its own kind.

Smilodon had jaws that could 120 degrees while on the other hand, today's lions can only open their jaws at 65 degrees. Smilodon also had and neck muscles that let it stab prey with its deadly maxillary canine sabre teeth, while its jaws were weak as a result of its long canines; its bite strength was comparable to a large dog and much weaker than that of a lion. Its front incisor teeth may also have been used to rip away strips of flesh from the bones of its prey.

Studies by Mauricio Anton et al., also show it could shear off flesh from kills using its carnassial teeth. It is unknown if Smilodon could hunt after lost its teeth but several paleontologists and biologists suggest it could be fatal for the big cat: however, some fossils of Smilodon have been found with healed wounds, indicating injured cat was getting food from an external source which gives credit to it possibly living in prides like modern lions or perhaps in packs akin to those of wolves as there is no size difference between male and female Smilodon recovered from various fossil sites such as Rancho La Brea.

Smilodon's hunting behavior was interpreted as ambush strategy, sneaking as close to its prey as possible before leaping on it cause it was so slow and had strong yet stocky legs . After pinning its victim down with its powerful front legs, Smilodon would use its powerful neck muscles to drive its saber teeth into the neck of its prey. Some scientists however disagree with this, and believe it targeted the belly of its prey. No modern cat hunts with a strategy that aims for the belly. Some like jaugars and cougars/pumas sometimes target the head but not the stomach.

Such strategies are filled with problems; aiming for the stomachs of prey leaves the cat vulnerable to a retaliatory kick. Another problem regarding belly bite strategies is that stomach bites using saber teeth only create shallow flesh wounds that create only superficial damage.

A bite to the throat meanwhile, allows the cat to sever the jugular veins, carotid arteries and trachea while simultaneously controlling and stifling the animal's movement without much risk of tooth breakage.

Smilodon's enormous canines were likely an adaptation for making swifter kills than modern cats. Such effective weapons allowed Smilodon to kill quickly and eat fast without fear of competitors stealing its hard-won meals.

Smilodon cubs have been found in the La Brea Tar Pits, and it is made clear from their dentition that they were born with teeth, not unlike hyenas, and that their milk sabers were serrated for eating portions of a carcass that adults could not. They also took three years to grow to full maturity, with their adult sabers growing in around one-and-a-half years of age.

Paleoecology[]

Painting of animals around a lake

Environment of what is now White Sands National Park, with S. fatalis in the reeds in the right foreground

Smilodon was an inhabitant of relatively warm climates, and it was present throughout the warmer areas of the American continents during the Ice Age. Isotope ratio analysis indicates that Smilodon predominantly fed on ungulates such as camels, horses, and bison. However, mastodons, mammoths, ground sloths, and even the armored Glyptotherium were components on its menu.

Smilodon preferred heavily vegetated areas, and probably dwelled in forested habitat. In South America, Smilodon hunted such animals as Macrauchenia, Toxodon, and horses. Dire wolves, American lions, jaguars, Homotherium, and short-faced bears shared its range on both continents, creating intense competition.

Range[]

Great American Biotic Interchange examples

Animals that participated in the Great American Interchange, with North American migrants like S. populator (lower right) in blue

Smilodon evolved and most commonly lived in North America. When, in the Pliocene, North and South America finally came together and formed a land bridge, Smilodon was a part of the Great American Exchange; while commonly depicted as being the primary cause of the extinction of sparassodonts like Thylacosmilus and the phorusrhacid terror birds, Smilodon was not the cause for their extinction, as Smilodon gracilis lived alongside the phorusrhacid Titanis and Thylacosmilus died out four million years ago, well before Smilodon evolved.

Extinction[]

Panthera leo atrox and Smilodon fatalis Page

Skeletons of S. fatalis (left) and the American lion, two large North American felids which went extinct during the Late Pleistocene, George C. Page Museum

Its still unknown what caused the extinction of this genus, but a combination of climate change, possible competition with humans (though no evidence suggests this), and the extinction of the large animals it hunted may have contributed to its demise.

JPInstitute.com Description[]

Also spelled Saber Toothed Cat, these were among the most successful creatures ever to live on Earth. They appeared almost 30 million years ago and became extinct only 10,000 years ago, most likely because man hunted them and man also killed off much of their prey. They are best known because of their distinctive fangs, which were as long as 6 inches. An interesting fact is that they needed to open their mouths more than 90 degrees in order to be able to bite. Another interesting fact is that, because it would have been relatively easy to break a saber, they would probably have used their teeth to bite into the bottom of the neck of their prey and slash it open as opposed to biting where they might hit a bone.

Appearance in other media[]

Jurassic Park[]

Smilodon appeared in the TV series Jurassic World: Camp Cretaceous.

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