Temporal range: Early Pleistocene – Early Holocene
|An artist's interpretation|
|Genus:||Smilodon Lund, 1842|
Smilodon was a genus of prehistoric cat belonging to the Machairodontinae. It was the last and largest of the sabertooth cats, ranging from North to South America during the late Pliocene to the end of the Pleistocene. Commonly referred to as a Saber-toothed tiger, it is by no means related to modern tigers or other pantherines, as it belongs to a completely extinct line of cats.
Smilodon was the heaviest-built of all machairodontine cats. Smilodon populator in particular was the heaviest, at 800 lb. 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 around4 30-600 lb. Smilodon gracilis meanwhile, was the smallest species, estimated to be about the same weight as a jaguar, maxing out at 360 lb. in weight.
Anatomy and PaleobiologySmilodon was the largest sabre-toothed cat (popularly known as the sabre tooth tiger). Smilodon 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), but much heavier. Smilodon had relatively short, muscular legs and a short, bobbed tail a bit like that of a modern day bobcat. 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 one of ambush, sneaking as close to its prey as possible before leaping on it. 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. 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.
PaleoecologySmilodon 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.
RangeSmilodon 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 were 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 extinctions, as Smilodon gracilis lived alongside the phorusrhacid Titanis and Thylacosmilus died out four million years ago, well before Smilodon evolved.
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.
In the Media
- The Fifth episode of Walking with Beasts.
- Wild New World aka Prehistoric America.
- Ice Age Giants.
- See Smilodon/Gallery