What comes to mind when you think of saber-toothed tigers? Most people will first think of the image of Diego in the movie "Ice Age" - a short-tailed big cat with two dagger-like teeth. Although this image does belong to the saber-toothed tiger subfamily, a dazzling family that once stood at the apex of the earth's ecological chain, it is not a taxonomic definition of the "saber-toothed tiger".
The real saber-toothed tiger usually refers to the genus Machairodus, and the upper canine teeth of the members of this genus are far less exaggerated than depicted in the movie. Scientists speculate that when they live, the tusks may only show a short cut. The image of the saber-toothed tiger used in the movie actually comes from another branch of the saber-toothed tiger family, the blade-toothed tiger genus Smilodon.
American Museum of Natural History's Depiction of the Bladed Tiger of Destruction | Charles R. Knight / Wikimedia Commons
Dynasties on the South American continent
The blade-toothed tiger can be described as the last glory of the saber-toothed tiger subfamily, among which the Smilodon populator living in South America is the largest and strongest vein among the many evolutionary branches of this family, and its largest individual can reach 2.7 meters long and weigh 400 kilograms, which can be called the most peculiar and eye-catching form of the saber-toothed tiger.
However, even such a powerful tiger as the Bladed Tiger of Destruction could not escape the fate of extinction. The legend of the rise and fall of this experience and eventual disappearance begins with the rise and fall of dynasties on the South American continent. In the middle Cretaceous period 106 million years ago, massive volcanic activity on the seabed continued to drive continental separation and the ocean floor to rise, generating the highest sea level ever recorded, and the South American continent began its drift for nearly 100 million years. After the extinction of the dinosaurs, chocobo crocodiles and cranes that inherited the mantle of dinosaurs became the new owners of this lost continent.
The ecological reconstruction of Pleistocene Brazil, in addition to the blade-toothed tiger, there are also South American elephants such as Notiomastodon, sloth's distant relative Eremotherium, etc., author Julio Lacerda | Mário André et al. / Revista Brasileira de Paleontologia (2020)
After that, the South American continent experienced and several global temperature drops, and the once hot and humid climate returned to cold. Winter has arrived, large areas of forests and swamps have disappeared, and permafrost areas have reappeared, so the chocobo crocodiles, which are warmer animals with little resistance to cold weather, are soon completely destroyed, and the crane family has become the only overlord of the South American continent. However, the earth overlords in a remote corner did not laugh to the end, and an epic crustal movement 3 million years ago, the Panama Land Bridge, rose from the bottom of the sea, making the North and South American continents connected from then on. The existence of the land bridge brought about a grand migration of North and South American creatures, so the blade-toothed tiger chasing its prey also entered the new world of the South American continent, and soon ended the 60 million-year rule of the Crane Dynasty and replaced it as the new king of the continent.
Destruction Blade Tooth Tiger Skeleton | Javier Conles / Wikimedia Commons
Violent double knife man
The success of the Blade Tooth Tiger is due to their unique body structure. The blade-toothed tiger has the longest upper canine teeth of the saber-toothed tiger family, of which the upper canine teeth of the saber-toothed tiger can even reach nearly 30 centimeters. These exaggerated canine teeth are broad and flattened on the sides, and the rear part is as thin and sharp as a blade, like two sabers embedded in the sides of the maxilla. This characteristic structure is not decorative, but an efficient hunting tool.
The correct use of tusks is not to cut and tear, but to plunge into the throat of the prey at the right time, and then pull out after cutting off the trachea and arteries in the neck in an instant, achieving a one-hit death. However, there are many risks behind this seemingly dashing assassination action, such as the teeth after piercing into the prey's body, if they are not well fixed during the struggle, they are likely to hit the hard bones of the prey and break, which is undoubtedly fatal to the devastating blade-toothed tiger that relies on tusks to hunt.
The upper canine teeth of the Blade Tooth Tiger of Destruction | Fernando da Rosa (Fedaro) / Wikimedia Commons
In addition, the tusks occupy a large amount of oral space, so that the lower canine teeth of the destructive blade tiger take on a incisorized form, changing from puncture to more fixed function. In addition, in order to be able to successfully stab the long upper canine teeth into the prey, the upper and lower jaw tension and convergence of the blade-toothed tiger far exceeded that of the living lion and tiger, reaching a staggering 120 ° (about 60 ° for lions and tigers). The muscles that control tension have become more developed, corresponding to the reduction of the muscles that control the bite force, according to the model estimates that the bite force of the bladed tiger may be only about half that of the living big cats, and the appearance of tusks has also brought many drawbacks.
The curvature of the skull of the deadly Bladed Tiger (Smilodon fatalis), a close relative of the Destroying Bladed Tiger, and the extinct Thylacosmilus atro in South America, | Stephen W Wroe et al. / PLoS ONE (2013)
In the evolution of the "partial door martial art" using tusks, the neck muscles of the blade-toothed tiger became extremely thick and developed, so that its head could remain stable in the event of fighting with prey. Not only that, but the forelimb bones of the blade-toothed tiger have become unusually thick, and the bones are attached to a large number of knotted muscles, which can knock down and control the prey more quickly and quickly, and the huge retractable claws can also firmly fix them on the prey. At the same time, the well-developed upper limb muscles allow the blade-toothed tiger to send its tusks deep into the throat of the prey in a similar "stabbing" movement when performing the assassination, using the strength of the body muscles to make up for the lack of bite force. Don't worry about how the bladed tigers should eat after successful hunting, scientists have found that the split teeth on their sides are unusually developed, and perhaps the blade-toothed tigers eat from the side in a crooked head killing.
The rise and fall of the "rich and handsome" life
The sharpness of the tusks, the strength of the muscles. These two factors made the blade-toothed tiger one of the successful carnivores of the time, and these traits were further strengthened in the evolutionary process, and the final destroying blade-toothed tiger even resembled a large bear with a long knife. The reason for this may be explained by a controversial law. In the 19th century, the American paleontologist Edward Drinker Cope found that the size of animals in the fossil record often showed a trend of increasing, so he believed that "gigantic" was one of the trends in biological evolution, and later generations called this trend Kopp's law.
The Skull of the Devastating Bladed Tiger at the Zoological Museum of the University of São Paulo | Wilfredor / Wikimedia Commons
Although Kopp's law has many limitations, it also reveals some essential phenomena in natural selection: for example, larger and stronger animals are more likely to gain the favor of the opposite sex, and they are less likely to be hunted by predators, so that animals do have a tendency to become larger in the absence of drastic changes in the environment. For predators, this is undoubtedly an arms race, in order to better hunt gradually larger prey, can penetrate deeper and thicker prey skin and muscles, the destruction of the bladed tiger thus has the largest physique and longest canine teeth of the bladed tiger family, but also has the excellent hunting ability to capture many giant mammals at that time. For humans at that time, the existence of such a perfect hunting machine was indeed creepy.
In the Tar Pits of La Brea, the Genus Bladetooth and dire wolves compete for the carcasses of mammoths, | by Robert Bruce Horsfall Wikimedia Commons
However, going farther and farther in one direction of evolution also means that it is becoming more and more difficult to turn back. The large-scale did improve the destructive blade-toothed tiger's ability to compete for hunting, but it also reduced its resilience to environmental change, as did many giant mammals of the time. As temperatures warmed up at the end of the glacier, large numbers of giant mammals died out of their inability to adapt to drastic environmental changes. The loss of large prey makes it much more difficult to hunt the destroying blade-toothed tiger, and its overly strong body is not suitable for hunting agile small prey. At the same time, the strong rise of human beings in the north became the last straw that crushed the camel, and about 10,000 years ago, the last surviving blade-toothed tiger came to the end of its life, thus announcing that the saber-toothed tiger family withdrew from the stage of earth evolution and became fossil and history.
This article is from the species calendar, welcome to forward
If you need to reprint, please contact [email protected]