By Andrea Hargraves 
Close your eyes and imagine that you are face to face with a cat with sword teeth. You will most likely see in your mind’s eye the long, curved upper canines – especially the sinister ones because those dagger-shaped teeth were visible even when the cat closed its mouth.
What appears in your imagination may not be true, at least for a family of cats with teeth that was one of the most widespread in the ancient history of the Earth.
In a study published last month in Quaternary Science Reviews, a team of researchers argued that many artistic reconstructions homotherium barking are wrong. Pictures of sharp-toothed cats need to be revised, because the animal’s defining feature was a weapon hidden until the cat was ready to pounce or open its mouth.
The homotherium barking “It was the strongest of the ancient world’s most powerful saber-toothed cat in the ancient world,” said paleontologist Mauricio Anton, an expert on toothed cats and one of the study’s authors. According to the fossil record, Homotherium first appeared about 4 million years ago, during the Ice Age.
The species lived from the southern tip of Africa, through Eurasia and even South America. A fossil site in Friesenhan Cave in Texas has suggested that groups of saber-toothed animals could have hunted en masse to take down mammoths. The species became extinct 10,000 years ago.
The cat was the size of a lion, weighed up to 250 kilograms, and had long, serrated upper fangs in the shape of a sword. In an article written by Anton in 2009, he concluded that “the tips of Homotherium’s swords were visible in life, protruding behind the lips,” even when the cat was at rest. In other words, Homotherium fits the stereotype of the saber-toothed cat.
Recently, Anton began to wonder if he and other paleontologists were misunderstanding a cat’s killer teeth.
For decades, nearly everything scientists knew about saber-toothed cats came from the fossils and anatomy of modern big cats. “When you dissect a dead big cat, the lips are in a certain position because the muscles that control the lips relax,” Anton said. “That’s where our data came from.”
Then, in 2016, while watching a video he had taken of a gorgeous lion yawning in the Okavango Delta in Botswana (Africa), Anton noticed something he had never seen before: “The lower lip was twitching with the mouth closed, and before full closing., It included Dog’s head. I thought, ‘Do I really see this?’ It was a eureka moment.”
To understand the implications of their observation, Anton and a team of scientists studied live big cats in minute detail. They analyzed the anatomy of the fossils with what Anton described as “new eyes.” They performed a 3D tomographic scan of an intact 3-million-year-old fossil Homotherium latidines Excavated in Perrier, France.
Combining these techniques provides a “tremendous amount of information that we can use to infer what extinct cats would look like in life,” said Gemma Silicio, a postdoctoral researcher at Comenius University in Slovakia and co-author of the study.
Their studies confirmed that there was simply no room for the lower lip and soft tissue to fit between the upper Homotherium’s canines and gums. But there was room to hide the fangs opposite the closed part of the jaw, the mandible.
Whatever their aesthetics, predatory-toothed cats have remained fearsome predators. Unlike modern big cats such as lions and tigers, Homotherium’s narrow, blade-like teeth were “precision weapons,” Anton said. “When the swords cut the arteries of the neck, the prey lost blood very quickly and died within seconds,” he added.
The lion’s upper fangs are about 3.7 cm long. Those of Homotherium were 7.3 cm. The largest sword-toothed cat, Smilodon fatalis weighing 408 kg, could have reached a length of 14.7 cm. That is why the new findings do not apply to Smilodon teeth: no jaw can accommodate such teeth.
The study authors still wonder where such subsequent investigations might lead. “We know about 30 to 40 species of cats with sharp teeth, but there is still a lot to be found,” Celicio said. Earlier this year, scientists in China described a previously unknown dwarf tooth and another the size of a leopard leopard.
According to Anton, this might just be the beginning. “We have a whole biosphere in the drawers of the museum waiting to be discovered,” he said.
Translated by Luis Roberto M. Gonsalves