Smilodon fatalis (Leidy 1868)

The social pattern of this cat is unknown. It has been suggested, based on the abundance of S. fatalis fossils in proportion to prey animals trapped in the La Brea tar-pits,[6] that they were packs of scavengers, lured in by the distress calls of trapped prey. This possibility was tested in 2008 by Chris Carbone (of the Zoological Society of London), who documented the responses of African predators of the Serengeti and Kruger National Park to recorded distress calls of prey species; it was determined that playbacks of prey sounds attract social carnivores, but not solitary hunters.[7] Additionally, some fossils show healed injuries or diseases that would have crippled the animal. Some palaeontologists see this as evidence that saber-toothed cats were social animals, living and hunting in packs that provided food for old and sick members. Living in groups might also allow more effective competition with social lions and wolves. The canine teeth and body size of Smilodon were about the same in both male and female cats. This suggests that one theory about their teeth – that they were used by males to attract mates – is incorrect.

Smilodon probably preyed on a wide variety of large game including bison, deer, American camels, horses and ground sloths. As it is known for the saber-toothed cat Homotherium, Smilodon might have killed also juvenile mastodons and mammoths. The La Brea tar pits in California trapped hundreds of Smilodon in the tar, possibly as they tried to feed on mammoths already trapped. The Natural History Museum of Los Angeles County has many of their complete skeletons.

Modern big cats kill mainly by crushing the windpipe of their victims, which may take a few minutes. Smilodon’s jaw muscles were probably too weak for this and its long canines and fragile skull would have been vulnerable to snapping in a prolonged struggle or when biting a running prey. Research in 2007 concluded that Smilodon more probably used its great upper-body strength to wrestle prey to the ground, where its long canines could deliver a deep stabbing bite to the throat which would generally cut through the jugular vein and / or the trachea and thus kill the prey very quickly.[8] The leaders of this study also commented to scientific journalists that this technique may have made Smilodon a more efficient killer of large prey than modern lions or tigers, but also made it more dependent on the supply of large animals. This highly-specialized hunting style may have contributed to its extinction, as Smilodon’s cumbersome build and over-sized canines would have made it less efficient at killing smaller, faster prey if the ecosystem changed for any reason.[4]

Research upon which African carnivores response to playback of animals in distress has been used to analyse the finds of animal species and their numbers at the La Brea Tar Pits. Such playbacks find animal distress calls such as would come from animal trapped in the tar pit would attract pack hunters such as lions and spotted hyenas, not lone hunters . Given the carnivores found at tar pits were predominately Smilodon and the social dire wolf, this suggests that the former like the later was also a social animal.[9] One expert, who found the study convincing, further speculated that if that was the case, then Smilodon's exaggerated canine teeth might have been used more for social or sexual signaling than hunting.[10][Full citation needed] However, the lack of sexual dimorphism in the canine teeth refutes this proposal.

Smilodon fatalis, famous for being one of the most well studied “sabre toothed cats” was discovered and named by Leidy in 1868. This is a relatively recent species known only from the Pleistocene (2.6 ma to 10 kya).They are most well known from the La Brea tar pits, located in Los Angeles, California.The La Brea tar pits are a series of natural asphalt pits that often trapped animals and preserved them for scientists to study. Current research suggests it was an ambush predator, taking advantage of unsuspecting prey to quickly pounce and incapacitate with a single bite. Their prey were predominantly large consumers that fed primarily on grass, such as deer and horses.

The morphology of the Smilodon skull is difficult to describe, primarily because they demonstrate great variation among individuals of the same species. This variability is difficult to attribute to any pattern, such as age or sex of the individual. It is, however, worth noting that 36% of individuals exhibit localized depressions in the upper, back part of the skull. This is the area of attachment for the chewing muscles, and the depressions seem to indicate high stress from chewing and biting in roughly a third of individuals.

Smilodon fatalis is primarily known from the fossils in the La Brea tar pits, in Los Angeles, California. The pits are natural sources of asphalt that trap many animals and are usually dominated by fossils of predators.It is thought that the struggles and cries of a prey species that fell into the tar and were trapped would attract predators.The predators would themselves become trapped when they attempted to attack the trapped prey.Predators such as Smilodon were trapped while trying to prey on the already trapped animals. Other predators known form the surrounding environment include dire wolves, the short faced bear, the American lion, and the Scimitar cat. These animals would have been preying on the local fauna such as mastodon, mammoths, deer, American horse, large sloths, and other similar herbivores.The fossils in the pit have been dated back to 38,000 years ago.

They are among the largest felids, the heaviest specimens of this massively built carnivore may have exceeded 400 kg (880 lb). A fully-grown Smilodon weighed approximately 55 to 400 kg (120 to 880 lb), depending on species. It had a short tail, powerful legs, muscular neck and long canines. Smilodon was more robustly built than any modern cat. Its gait was more like a bear than a feline.

Smilodon had relatively shorter and more massive limbs than other felines. It had well developed flexors and extensors in its forepaws,[citation needed] which enabled it to pull down large prey. The back limbs had powerfully built adductor muscles which might have helped the cat's stability when wrestling with prey. Like most cats, its claws were retractable.


Smilodon is most famous for its relatively long canines. They are the longest canines of the saber-toothed cats at about 28 cm (11 in) long in the largest species Smilodon populator. They were probably built more for stabbing than slashing. Despite being more powerfully built than other large cats, Smilodon actually had a weaker bite. Modern big cats have more pronounced zygomatic arches, while Smilodon had smaller zygomatic arches which restricted the thickness and therefore power of the temporalis muscles, and thus reduced Smilodon’s bite force. Analysis of its narrow jaws indicates that it could produce a bite only a third as strong as that of a lion.[4] There seems to a be a general rule that the saber-toothed cats with the largest canines had proportionally weaker bites. However, analyses of canine bending strength (the ability of the canine teeth to resist bending forces without breaking) and bite forces indicate that saber-toothed cats' teeth were stronger relative to the bite force than those of modern "big cats".[5] In addition, Smilodon could open its jaws 120 degrees, whereas the lion can only open its jaws to 65 degrees. It has been suggested that smilodon's smaller temporalis muscles, (controling much of the bite force) was not used in the killing prey, but rather, the immense strength of the neck of smilodon allowed it to stretch its jaws around the throat and press its canines into the prey with the usage of such immense neck and forelimb muscles rather than an actual bite: the penetration was the result of the neck flexors instead of the jaw muscles, as according to this hypothesis.

Smilodon fatalis has the classic extended, re-curved canines that have made it one of the most popular and studied Pleistocene (2.6 million to ten thousand years ago) predators. These canines are flattened and curved like a sabre sword, hence, the name sabre-tooth tiger. There are no extant mammalian predators with sabre teeth.Modern members of the cat family have conical or cone-shaped canines. There is some evidence that these sabre teeth would have actually presented a number of challenges for Smilodon fatalis and would have made many aspects of feeding much harder than in cats with a traditional set of conical (and much smaller) canines (as in the modern predators today).

The elongation of the canines is coupled with an increase in the overall gape, or maximum opening of the jaw. However, increasing the gape has the effect of drastically reducing bite force, especially at the exaggerated gapes presented by the enormous canines of Smilodon fatalis. In modern predators with a very strong bite force, like hyenas, the point at which the upper and lower jaws join forms an interlocking mechanism that allows considerable bite force.In Smilodon fatalis the point at which the upper and lower jaws join does not form a strong interlocking mechanism. This loose joint would have allowed Smilodon fatalisto open its jaws very wide, but at the expense of being able to clamp their jaws closed on prey.Thus, these canines, which grow increasingly exaggerated as the animal ages, actually decrease the overall bite force substantially, begging the question: how did they eat?

The diet ofSmilodon fatalis has been discussed extensively. However, it is actually poorly understood, mostly because of the hot debate over feeding strategies. What is definitively known is that they ate prey from transitional areas between wooded and open habitats. This is consistent with the ambush predator hypothesis, and is generally accepted. It is also believed that their primary targets were large herbivores because studies have shown that they did not eat other predators, but rather fed primarily on consumers eating grasses. Thus, it is hypothesized that they ate animal such as deer, antelope, bison, and baby mammoth.

The North American Pleistocene (2.6 million to 10,000 years ago) is characterized by periods of glaciation and interglaciation.These were periods of very rapid warming followed by very gradual cooling. This would have presented enormour environmental challenges for a predator and would have forced great adaptability in prey and habitat.Smilodon fatalis lived through these changing environemnts.Perhaps one of the biggest challenges Smilodon fatalis would have faced was that of climate change.

It is believed that Smilodon fatalis inhabited marginal and transitional areas between true woodland and true plains. This type of habitat is not preferred by any modern cats, but could have been ideal for Smilodon fatalis because it would have allowed it to prey on animals from the transition between wooded and open habitats. They differ from one of the other large predators at the time, the dire wolf, which is believed to have crossed deep into the wooded and the open areas.

Over time, three distinct hypotheses for Smilodon fatalis feeding have been suggested. The earliest hypothesis, posed before the bite force limitations were well understood, was that of Smilodon as an active hunter. This hypothesis involved Smilodon fatalis hunting in much the same way as modern lions, by running down large prey and using the exaggerated canines to suffocate prey at the throat.

As bite force became a topic of study, it began to become apparent that Smilodon fatalis would have struggled to actively hunt prey the way modern lions do. The shape of the skull indicates that they would be unable to withstand the forces generated by struggling prey. Next, scientists suggested Smilodon fatalis was a carrion feeder, opportunistically taking advantage of dead carcasses and bullying smaller predators off of their kill. This hypothesis involves them using the enlarged canines to slash open the swollen bellies of already dead animals. It solves the bite force problem, but has a few issues of its own. Most notably, they would not be able to open their mouth wide enough for the canines to be used in a slicing manner.

Thus, a third hypothesis was put forth, and is widely accepted today. This places Smilodon fatalis in the role of an ambush hunter. The latest studies indicate that Smilodon fatalis possessed immensely powerful forelimbs, even stronger than modern big cats. They likely would have ambushed unsuspecting prey and, using the massive strength in their front limbs, knocked their prey over and pinned them. From this position, with the prey adequately restrained by the powerful front paws, they would have been able to bite at the throat and trachea and asphyxiate the animal without succumbing to the cranial strain (such as breaking of the jaw bones) caused by a thrashing animal. Contrary to the earliest research, modern microwear evidence (studying abrasions on the teeth) appears to suggest that Smilodon fatalis did not waste much and consumed at least some of the bone, similar to modern hyenas. Microwear studies use high-magnification images of teeth and compare the wear on the teeth to a library of wear patterns built from modern animals with known diets.Microwear patterns are thought to record only the most recent meals eaten by an animal.As a result, even in fossil species, they are a good predictor of what the animal would have been eating just prior to its death.

Modern felids show sexual dimorphism, or differences in male and female morphology. The degree of dimorphism is influenced by several factors, including competition between males for females. Lions, for example, have a high degree of competition for females. Because a single male controls a pride of many females, the largest and most powerful males are most successful. Tigers, in contrast, exhibit only a small amount of sexual dimorphism, with males being only slightly larger than females. Because single individuals tend to control their own territories males rarely come into contact and do not fight each other for mates.

Smilodon exhibits only a small amount of dimorphism. There is very little overall difference in size between males and females, and only a slight difference in the enlarged canines. Thus, it is believed that Smilodon shared a similar lifestyle and social structure to modern tigers, where males faced little competition for females. This suggests that Smilodon fatalis was solitary rather than a social big cat. Some authors have suggested thatSmilodon fatalis would have lived ins mall family groups with a single mated pair and their cubs.

Smilodon (pronounced /ˈsmаɪlədɒn/), often called saber-toothed cat or saber-toothed tiger, is an extinct genus of the subfamily machairodontine saber-toothed cats endemic to North America and South America living from the Early Pleistocene through Lujanian stage of the Pleistocene epoch (1.8 mya—10,000 years ago), existing for approximately 1.790 million years.

They are called "saber-toothed" for the extreme length of their maxillary canines. Despite the colloquial name of "saber-toothed tiger", Smilodon is not a tiger. Tigers belong to the the subfamily Pantherinae. The name Smilodon is a bahuvrihi from Greek: σμίλη, smilē, "chisel" and Greek ὀδoύς (odoús), "tooth", Genitive: ὀδoύς, ὀδόντος,odóntos.

The genus Smilodon was described by the Danish naturalist and palaeontologist Peter Wilhelm Lund in 1841. He found the fossils of Smilodon populator in caves near the small town of Lagoa Santa, in the state of Minas Gerais, Brazil.

A number of Smilodon species have been described, but today usually only three are recognized.

Smilodon gracilis, 2.5 million-500,000 years ago; the smallest and earliest species (estimated to have been only 55 to 170 kg (120 to 370 lb))[3] was the successor of Megantereon in North America, from which it probably evolved. The other Smilodon species probably derived from this species.
Smilodon fatalis, 1.6 million-10,000 years ago, replaced Smilodon gracilis in North America and western South America. In size it was between Smilodon gracilis and Smilodon populator, and about the same as the largest surviving cat, the Siberian Tiger. This species is estimated to have ranged from 250 to 360 kg (550 to 790 lb).[3] Sometimes two additional species are recognized, Smilodon californicus and Smilodon floridus, but usually they are considered to be subspecies of Smilodon fatalis.
Smilodon populator, 1 million-10,000 years ago; occurred in the eastern parts of South America and was the largest species of all machairodonts. It was 1.2 m (47 in) tall, 2.1 m (83 in) long and had a 30 cm (12 in) tail. With an estimated weight of 400 kg (880 lb), it was among the heaviest known felids.[3] Its upper canines reached 28 cm (11 in) and protruded up to 17 cm (6.7 in) out of the upper jaw.