Researchers have gained new insights into the evolutionary history of sabre-toothed mammals, revealing why these remarkable teeth developed multiple times throughout history. Sabre teeth are characterized by their exceptionally long, sharp canines that are slightly flattened and curved, differing from traditional rounded teeth. Evidence shows that these distinctive teeth emerged independently in various mammal groups at least five times, with fossils found across North and South America, Europe, and Asia.
Originating approximately 270 million years ago in mammal-like reptiles known as gorgonopsids, sabre teeth were later seen in species such as Thylacosmilus, which went extinct around 2.5 million years ago, and Smilodon, often referred to as sabre-toothed tigers, which thrived until about 10,000 years ago.
A recent study conducted by scientists from the University of Bristol analyzed the canines of 95 carnivorous mammal species, including 25 known for their sabre teeth. The researchers measured the shapes of these teeth to develop a comprehensive model and subsequently created 3D-printed replicas to conduct puncture tests, simulating the density of animal tissue with gelatine blocks.
Findings revealed that sabre teeth could puncture the test blocks with up to 50% less force compared to other teeth. The team evaluated tooth shape and performance through the Pareto rank ratio, assessing the balance of strength and puncture capability essential for carnivores.
According to researchers, the sabre teeth of animals like Smilodon were likely optimal for puncturing prey, albeit somewhat fragile. Historical fossil findings from sites like the La Brea Tar Pits support this theory, showing specimens with broken teeth. Other sabre-toothed species, such as the cat Dinofelis, showcased variations in tooth design that provided a more balanced approach between puncturing ability and strength.
Some sabre-toothed species had teeth that fell between optimal designs, potentially influencing their survival rates. “The characteristics that make a tooth proficient in one area can hinder performance in another,” noted a researcher, indicating the evolutionary trade-offs involved.
The extinction of sabre-toothed species is linked to significant environmental changes and the decline of their large prey, like mammoths. The study’s results suggest that giant teeth would have been less effective in hunting smaller prey, resulting in competition with more adaptable predators, such as modern cats with smaller teeth. Unable to rapidly adapt to shifting ecosystems, these specialized predators became extinct.
Experts believe that the absence of megafauna today may explain why sabre-toothed morphology has not re-emerged. The changing ecological landscape lacks the larger prey that these predators relied upon in the past.
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