Smilodon is a group of extinct cats. It is one of the most well-known saber-toothed predators and ancient mammals. Although often called the saber-toothed tiger, it was not closely related to tigers or modern cats. Instead, it belonged to the extinct group Machairodontinae, which split from the ancestors of living cats about 20 million years ago. Smilodon was one of the last surviving members of this group, along with another species called Homotherium. Smilodon lived in the Americas during the Pleistocene and early Holocene periods (2.5 million years ago to as recently as 8,200 years ago). The name Smilodon was first used in 1842 based on fossils found in Brazil. The name combines the words for "scalpel" or "two-edged knife" and "tooth." Three species are known today: S. gracilis, S. fatalis, and S. populator. S. gracilis likely evolved from another extinct cat called Megantereon, and the other two species may have descended from it. Many Smilodon fossils have been found at the La Brea Tar Pits in Los Angeles, making it the largest collection of Smilodon remains.
Smilodon had a stronger, more muscular body than any living cat, with powerful front legs and very long upper canine teeth. Its jaw could open wider than that of modern cats, and its canines were thin and fragile, designed for precise attacks. S. gracilis was the smallest species, weighing between 55 and 100 kilograms (121 to 220 pounds). S. fatalis weighed between 160 and 280 kilograms (350 to 620 pounds), stood about 100 centimeters (39 inches) tall, and measured 175 centimeters (69 inches) in body length. These two species are mostly found in North America, though some remains from South America have also been linked to them. S. populator, which lived in South America, was the largest species, weighing between 220 and 470 kilograms (490 to 1,040 pounds) and standing about 120 centimeters (47 inches) tall. It was one of the largest known cats. The color of Smilodon’s fur is unknown, but artists have suggested it may have had plain or spotted patterns.
In North America, Smilodon hunted large plant-eating animals like bison and camels. It remained successful even when encountering new prey in South America, such as Macrauchenia and ground sloths. Scientists believe Smilodon held its prey still with its front legs and bit it, but the exact way the bite was delivered is unclear. Researchers debate whether Smilodon lived alone or in groups, as evidence from its fossils and the behavior of modern predators could support either view. Smilodon likely lived in forested or bushy areas, which would have helped it ambush prey. However, S. populator may have hunted in open areas. Smilodon went extinct during the end-Pleistocene extinction event, which occurred around 13,000 to 9,000 years ago, along with many other large animals in the Americas. Its reliance on large prey may have contributed to its extinction. Factors such as changes in habitat, loss of prey species due to climate shifts, and the impact of early humans on prey populations are thought to have played a role in its disappearance.
Taxonomy
During the 1830s, Danish naturalist Peter Wilhelm Lund and his assistants collected fossils in the limestone caves near the small town of Lagoa Santa, Minas Gerais, Brazil. Among the thousands of fossils found, Lund identified a few isolated cheek teeth as belonging to a hyena, which he named Hyaena neogaea in 1839. After more fossils were discovered, including incisor teeth and foot bones, Lund concluded the fossils belonged to a distinct group of cats, though related to hyenas. He noted that the animal would have been as large as modern predators and more robust than any modern cat. Lund initially wanted to name the new group Hyaenodon, but since this name was already used for another prehistoric predator, he named it Smilodon populator in 1842. He explained that the name Smilodon comes from the Ancient Greek words smilē (meaning "scalpel" or "two-edged knife") and odóntos (meaning "tooth"), which can also be translated as "tooth shaped like a double-edged knife." He named the species populator as "the destroyer" or "he who brings devastation." Lund based the name on the shape of the incisors, and the large canine teeth were not known until 1846. By 1846, Lund had collected nearly every part of the skeleton (from different individuals), and more fossils were found in neighboring countries by other researchers in the years that followed. Later scientists used Lund’s original name neogaea instead of populator, but neogaea is now considered an invalid name because it lacked a proper description and no type specimen was designated. Some South American fossils have been classified into other groups, such as Smilodontidion riggii, Smilodon (Prosmilodon) ensenadensis, and S. bonaeriensis, but these are now considered to be the same as S. populator.
Fossils of Smilodon were discovered in North America starting in the second half of the 19th century. In 1869, American paleontologist Joseph Leidy described a jaw fragment with a molar found in a petroleum bed in Hardin County, Texas. He classified the specimen into the genus Felis (used for most cats, both living and extinct), but noted it was distinct enough to be part of its own subgenus, F. (Trucifelis) fatalis. The species name fatalis means "deadly." In 1880, American paleontologist Edward Drinker Cope noted that the F. fatalis molar matched that of Smilodon and proposed the new name S. fatalis. Most North American fossils were limited until excavations began at the La Brea Tar Pits in Los Angeles, where hundreds of S. fatalis fossils were found starting in 1875. S. fatalis has been linked to other names like S. mercerii, S. floridanus, and S. californicus. American paleontologist Annalisa Berta argued that the original S. fatalis fossil was too incomplete to be a proper type specimen, and some scientists have suggested it might be the same as S. populator. Nordic paleontologists Björn Kurtén and Lars Werdelin supported the idea that S. fatalis and S. populator were different species in a 1990 study. A 2018 study by John P. Babiarz and colleagues concluded that S. californicus, represented by fossils from the La Brea Tar Pits, was a separate species from S. fatalis, and more research is needed to clarify the group’s classification.
In his 1880 article about extinct cats, Cope named a third Smilodon species, S. gracilis, based on a partial canine found in Port Kennedy Cave near the Schuylkill River in Pennsylvania. Cope noted the canine was smaller and more compressed at the base than those of other Smilodon species. The name gracilis refers to the species’ lighter build. Fewer and less complete remains of S. gracilis have been found compared to other Smilodon species. At times, S. gracilis has been grouped with other genera, such as Megantereon and Ischyrosmilus. Currently, S. populator, S. fatalis, and S. gracilis are considered the only valid Smilodon species. Features used to classify other names as separate species have been dismissed as differences between individuals of the same species. Smilodon is one of the most famous prehistoric mammals and is the state fossil of California.
For many years, Smilodon was the best-known saber-toothed cat, and the two terms are often confused. The term "saber-tooth" refers to a group of extinct predatory mammals that evolved long upper canine teeth and related skull and body adaptations. This group includes animals from different families, such as Gorgonopsia, Thylacosmilidae, Machaeroidinae, Nimravidae, and Machairodontinae. Within the cat family (Felidae), the subfamily Machairodontinae is called "saber-toothed cats" and is divided into three groups: Metailurini (false saber-tooths), Homotherini (scimitar-toothed cats), and Smilodontini (dirk-toothed cats), to which Smilodon belongs.
Members of Smilodontini are defined by their long, slender canines with fine or no serrations, while Homotherini have shorter, broader canines with coarser serrations. Metailurini had less specialized canines and are not always classified as part of Machairodontinae. Despite its common name, "saber-toothed tiger," Smilodon is not closely related to modern tigers (which belong to the subfamily Pantherinae) or any other living cat. A 1992 study using ancient DNA suggested Smilodon should be grouped with modern cats, but a 2005 study and a 2006 study confirmed that Smilodon belongs to a separate lineage that diverged from living cats around 20 million years ago.
The earliest true cats appeared in the Oligocene period in Europe, such as Proailurus, and the first saber-toothed cat with features similar to modern cats was the Miocene genus Pseudaelurus. Early saber-toothed cats had skull and jaw shapes similar to modern clouded leopards (Neofelis). Over time, these cats evolved longer canines and wider jaws to kill large prey, but this adaptation reduced
Description
Smilodon was about the same size as modern big cats but had a stronger, more muscular body. S. gracilis was the smallest species, weighing between 55 and 100 kg (121 to 220 lb), similar in size to a jaguar. It was similar to Megantereon, another species of similar size, but had more advanced teeth and a skull shape closer to S. fatalis. Over time, S. gracilis individuals became larger on average, as seen in Late Irvingtonian fossils. S. fatalis was between S. gracilis and S. populator in size, weighing 160 to 280 kg (350 to 620 lb), with a shoulder height of 100 cm (39 in) and a body length of 175 cm (69 in). Its size varied depending on the climate, with larger individuals found during warmer periods. In Florida, S. fatalis grew larger from the Illinoian to the Wisconsin stage. It was similar in size to a lion but had a stronger, more muscular body, giving it a greater body mass. Its skull resembled Megantereon’s but was larger and had bigger canines.
S. populator was one of the largest known cats, standing 120 cm (47 in) tall at the shoulder and weighing between 220 kg (490 lb) and over 400 kg (880 lb), with one estimate suggesting up to 470 kg (1,040 lb). A large S. populator skull found in Uruguay measured 39.2 cm (15.4 in) long, suggesting the individual may have weighed 436 kg (961 lb). In contrast, the smallest adult S. populator specimen weighed 157–171 kg (346–377 lb), possibly due to environmental factors or because it belonged to a new species or subspecies. Compared to S. fatalis, S. populator had a more robust body, a longer and narrower skull, a straighter upper skull profile, higher nasal bones, a more vertical occiput, stronger leg bones, and slightly longer front legs relative to back legs. Large fossil footprints from Argentina, named Smilodonichium, measure 17.6 cm (6.9 in) by 19.2 cm (7.6 in), larger than those of a Bengal tiger.
Smilodon is best known for its long canine teeth, the longest among saber-toothed cats, reaching about 28 cm (11 in) in S. populator. These teeth were thin and had small ridges on both sides. The skull was strong and broad, with deep cheekbones that arched widely. The sagittal crest (a ridge on the skull) was prominent, and the forehead was slightly curved. The lower jaw had flanges on each side of the front. The upper front teeth were large, sharp, and angled forward. A gap existed between the front teeth and molars in the lower jaw, while the lower front teeth were wide, curved backward, and aligned in a straight line. The p3 premolar tooth in the lower jaw was present in early Smilodon fossils but absent in later ones, appearing in only 6% of La Brea fossils.
Smilodon had a shorter lower back, high shoulder blades, a short tail, and broad limbs with short feet. Scientists debate whether Smilodon had sexual differences in size. Some studies of S. fatalis fossils found little difference between males and females. However, a 2012 study noted that while S. fatalis fossils show less size variation than modern lions, they still show differences between sexes in some traits. Despite many fossils found, including ear bones, no baculum (a penis bone found in all modern cats) has been discovered in Smilodon. This has led to questions about whether Smilodon truly lacked this bone or if its absence in fossils is not enough evidence to conclude that.
Smilodon and other saber-toothed cats may have had plain or spotted coats, with spotted patterns likely being the original condition for cats. Studies of modern cats suggest open-habitat species often have uniform coats, while forest-dwelling species have more markings, though exceptions exist. Features like lion manes or tiger stripes are too unique to predict from fossils.
Traditionally, artists like Charles R. Knight, working with paleontologists, depicted Smilodon with features similar to modern cats. In 1969, G. J. Miller proposed Smilodon looked more like a bulldog, with a lower lip line, a retracted nose, and lower ears. However, paleoartist Mauricio Antón and others argued in 1998 that Smilodon’s facial features were not very different from other cats. Antón noted that modern large cats have elastic lips that allow them to open their mouths without tearing skin, a trait that may have existed in Smilodon. He emphasized using the features of modern cat relatives to accurately restore Smilodon’s appearance, supporting Knight’s original depictions. A 2022 study by Antón and colleagues found that Smilodon’s upper canines were visible when its mouth was closed, unlike those of Homotherium.
Paleobiology
Scientific studies show that Smilodon was a daytime predator. Smilodon fatalis had larger hyoid bones compared to modern cats, which may have allowed it to make deeper sounds. Like roaring cats, Smilodon had the same number of hyoid bones, but their shape was more similar to those of cats that purr.
The brain of Smilodon had patterns similar to those of modern cats. This suggests that the brain had more complex areas for hearing, seeing, and controlling limb movement. Felid saber-tooth cats generally had smaller eyes that were not as forward-facing as those of modern cats. Modern cats have good binocular vision, which helps them move in trees. Research found that Smilodon fatalis had slightly fewer genes related to smell than modern cats. A domestic cat has 677 olfactory receptor genes, while Smilodon fatalis had about 600. This suggests that Smilodon relied less on smell for daily activities than modern cats.
Smilodon likely hunted by hiding in dense vegetation. Its limb proportions were similar to those of modern forest-dwelling cats, and its short tail would not have helped it balance while running. Footprints found in Argentina in 2019, named Felipeda miramarensis, may have been made by Smilodon. If correct, the footprints show that Smilodon had retractable claws, plantigrade feet, and forelimbs stronger than its hindlimbs. It likely hunted by ambushing prey. Unlike its ancestor Megantereon, which could climb trees, Smilodon was probably completely terrestrial because of its weight and lack of climbing features. Its heel bone was long, suggesting it was a good jumper.
Smilodon’s strong forearm muscles helped it pull down and hold large prey. Studies of the bones of Smilodon fatalis show that its humerus (upper arm bone) was 15% thicker than that of modern big cats of similar size. This made its arms stronger and better at handling heavy prey. The thickness of its thigh bones was similar to that of modern cats.
Smilodon was an apex predator that hunted large mammals. Bones of Smilodon fatalis found in the La Brea Tar Pits show that it often hunted bison (Bison antiquus, which was larger than modern bison) and camels (Camelops). Evidence suggests it may have also hunted Glyptotherium, as a juvenile Glyptotherium skull found in Arizona had marks matching Smilodon’s teeth. Smilodon gracilis, another species, ate peccaries (Platygonus) and llamas (Hemiauchenia). Studies of its teeth show that it had flexible eating habits. During cold periods, Smilodon gracilis may have competed with Edward’s wolf (Canis edwardii) for food. During warmer periods, it hunted different prey than the wolf. Dental studies suggest Smilodon gracilis ate tougher foods during cold periods, such as large animals with tough hides.
In the La Brea Tar Pits, Smilodon fatalis likely hunted forest animals like tapirs, deer, and forest bison, while dire wolves (Aenocyon dirus) and American lions (Panthera atrox) hunted animals in open areas like grasslands. The variety of prey in La Brea was similar to that in modern East Africa.
When Smilodon migrated to South America, its prey changed. Bison were not present, and horses and elephants were different. However, Smilodon populator, a South American species, thrived by hunting native animals like ground sloths (Lestodon, Megatherium), horses (Hippidion), and camels (Macrauchenia). In Brazil, Smilodon populator hunted animals such as Toxodon, Pachyarmatherium, glyptodonts (Panochthus), Palaeolama, Catonyx, Equus neogeus, and crocodiles (Caiman latirostris). Studies show it hunted in both open and forested areas. Its main prey in Brazil was Nothrotherium maquinense.
Differences in diet between North and South American Smilodon species may be due to differences in available prey on each continent. Smilodon may have avoided eating bones, leaving food for scavengers. Fossilized feces (coprolites) from Smilodon populator in Argentina contain remains of ground sloth bones and a llama bone, showing it ate bones. This suggests Smilodon had a varied diet. Studies of teeth from La Brea also show Smilodon ate both meat and bones. It may have scavenged from dire wolf kills. Some older theories suggested Smilodon was a pure scavenger, but this is not supported today, as no modern land mammals are pure scavengers.
Smilodon’s canines were fragile because they were flat on the sides and could not bite into bones. To avoid breaking its teeth, Smilodon used its strong forelimbs to subdue prey before using its canines for quick bites. Rarely, Smilodon bit into bones, possibly during fights with other Smilodon or to compete with other predators. The force needed to break a Smilodon fatalis canine was estimated at 7,000 Newtons. For comparison, a similar-sized lion would need 8,243 Newtons, and a tiger would need 7,440 Newtons. Studies using computer models further support these findings.
Distribution and habitat
Smilodon lived during the Pleistocene epoch, which lasted from about 2.5 million years ago until 10,000 years ago. It may have been the most recent type of saber-toothed cat. S. fatalis lived in many different environments, including open grasslands, parklands, areas where woodlands met grasslands, and dense forests. Fossils of this group have been found across the Americas. The northernmost fossils of this group are from Alberta, Canada, and the southernmost fossils are from Patagonia, near the Strait of Magellan. In North America, habitats ranged from subtropical forests and savannahs in the south to treeless mammoth steppes in the north. Mixed areas of woods, shrubs, and grasses in southwestern North America supported large plant-eating animals such as horses, bison, antelope, deer, camels, mammoths, mastodons, and ground sloths. North America also had other saber-toothed cats, like Homotherium and Xenosmilus, as well as other large carnivores, such as dire wolves, short-faced bears (Arctodus simus), and the American lion.
S. gracilis entered South America during the early to middle Pleistocene, where it likely led to the evolution of S. populator, which lived in the eastern part of the continent. S. fatalis also moved into western South America during the late Pleistocene, and it was once thought that the two species were separated by the Andes Mountains. However, in 2018, a skull of S. fatalis was found in northern Uruguay, east of the Andes, which challenges the idea that the two species were geographically separated. In 2025, another skull of S. fatalis was discovered in southern Uruguay, where S. populator fossils were also found, suggesting that the two species may have lived together and possibly interbred. The American interchange brought together native and new species in South America’s prairies and woodlands. North American plant-eaters included elephants, horses, camels, and deer, while South American plant-eaters included toxodonts, litopterns, ground sloths, and glyptodonts. Native South American predators called Sparassodonta went extinct by the Pliocene and were replaced by North American carnivores such as dogs, bears, and large cats.
By the Early Pleistocene, S. populator and Arctotherium angustidens were the only two top predators in South America that reached a body mass of over 200 kg (440 lb). Arctotherium angustidens went extinct during the Middle Pleistocene. S. populator likely hunted large prey in open habitats like grasslands and plains, as shown by evidence from isotope ratios. This suggests that South American Smilodon species, like S. populator, may have been similar to modern lions. S. populator probably competed with the dog-like Protocyon but not with the jaguar, which mainly hunted smaller prey. However, physical characteristics suggest that S. populator was best suited for more closed environments.
Extinction
Smilodon, like many large animals in the Americas, disappeared around 10,000 years ago during a major extinction event. Its extinction is connected to the loss of large plant-eating animals, which may have made Smilodon too specialized for hunting large prey and unable to adapt. Before the Younger Dryas cooling event, Smilodon fatalis showed changes in skull shape that suggest it became more specialized for hunting large prey or responding to competition with other predators. Early ideas suggested that high rates of broken teeth in La Brea carnivores meant food was scarce, forcing them to eat prey completely. However, a 2012 study challenged this, arguing that larger predators have weaker teeth, and tooth breakage likely resulted from eating large prey. Analysis of remains showed La Brea carnivores used carcasses less than modern carnivores, with Smilodon consuming less tough tissue but not more bones. Other possible causes include climate change, competition with Homo sapiens (who arrived in the Americas around the same time Smilodon disappeared), or a mix of factors affecting many species during the Late Pleistocene extinction. The Younger Dryas cooling event may have reduced habitable areas for many species. Evidence suggests humans caused increased fires in Rancho La Brea, which may have contributed to the decline of large animals.
In the early 20th century, scientists thought Smilodon and Homotherium died out because they competed with faster, more general predators. It was once believed their long teeth made them poor hunters, but later research showed they had varied diets, including cows, horses, and camels, not just large animals. Other large cats, like the American lion and Miracinonyx, also went extinct during the Late Pleistocene. Saber-toothed and non-saber-toothed cats coexisted for over a million years, and the repeated evolution of saber-teeth in different species shows this trait was successful.
The last direct radiocarbon date for Smilodon fatalis is earlier than Smilodon populator by thousands of years. The latest Smilodon populator remains from the Jirau site are dated to 8,189–9,079 years before present, while the latest Smilodon fatalis from Rancho La Brea is dated to 13,025 years ago. A Smilodon fatalis specimen from Iowa is dated to 13,605–13,455 years before present. Remains from Cueva del Medio in Chile are dated to 10,935–11,209 years ago. The most recent carbon-14 date for Smilodon fatalis is 11,130 years before present, but these dates may not be adjusted for accuracy. This suggests the Rancho La Brea specimen is the youngest recorded, showing Smilodon fatalis went extinct before the Younger Dryas, unlike other regions where large animals declined during that time.