The secrets of the extinct American cheetah

The Miracinonyx trumani, commonly known as the American cheetah, lived in North America more than 13,000 years ago.

Despite its name, recent studies carried out at the University of Málaga (UMA) in Spain have revealed that it was more similar to the puma than to the modern cheetah, although with its own features that make it a unique species, of which it is not no analogous feline exists today.

UMA paleontologists, together with researchers from the University of Valladolid in Spain and the University of Wisconsin-Madison in the United States, have now provided new and revealing data on the characteristics of this extinct feline, mainly through the study of its method of hunting, which has been the subject of debate in recent decades.

The team is made up of, among others, Borja Figueirido, from the University of Malaga (UMA) in Spain, and Anthony Hotchner, from the University of Wisconsin-Madison in the United States.

By analyzing its skeleton, experts have shown that Miracinonyx trumani, despite having long and light legs, was not as prepared as previously thought to run after its prey, as Old World cheetahs do.

The approximate appearance of the typical adult individual of Miracinonyx trumani in life. (Image: NPS)

The results of the study also show that the Miracinonyx’s nails were retractable and that it had the ability to struggle with its prey, like other cats, with the exception of the cheetah.

“Although its appearance was very similar to that of a modern cheetah, its way of hunting was more like that of a puma,” says Borja Figueirido, from the UMA’s Paleontology Area, co-author of the study.

The experts focused especially on the elbow joint, which allows us to know if the animal is adapted to hunting by holding its prey with its front legs or can chase them at high speed.

Miracinonyx’s humerus was oval and elongated at the end closest to the elbow, implying that its forearm bones were further apart and therefore had the ability to hunt its prey by grabbing it, much like the puma.

“The case of cheetahs is really unusual, in a few seconds they can reach almost 100 kilometers per hour. They are the supercars of the savannah,” says Figueirido.

This is not the case of Miracinonyx, which, although it had a greater ability to manipulate its front legs, its physiognomy prevented it from reaching a speed similar to that of the modern cheetah. It was not, therefore, such a sprinting predator, says Alberto Martín Serra, also a UMA paleontologist and co-author of the study.

To reach this conclusion, the scientists examined a Miracinonyx skeleton found in a Wisconsin chasm and compared it to other modern cat species, including cougars, lions and bobcats.

“The detailed study of the bones has been carried out at the UMA. What we have done has been to scan in 3D the humeri of current cats and digitize homologous points to quantify their shape. The fossil was scanned by CT at the University of Wisconsin-Madison”, explains Figueirido.

The study is titled “Elbow-joint morphology in the North American ‘cheetah-like’ cat Miracinonyx trumani”. And it has been published in the academic journal Biology Letters.

study of brain architecture

Another recent study by this research team from the University of Malaga, published in the academic journal Science, corroborates this hypothesis. The paleontologists analyzed whether the brain architecture of Miracinonyx was similar to that of the cheetah, and the results, again, showed clear differences between one and the other.

Using 3D technology, the scientists virtually filled in the intracranial space where the brain is housed, obtaining an internal cast of the brain surface of Miracinonyx trumani, which they compared to the modern cheetah and puma.

The brain surface of Miracinonyx turns out to be more similar to that of the puma than the cheetah: the old American cheetah was not cognitively prepared to hunt by high-speed running, among other things because it had an underdeveloped sinus, like the puma. .

“Probably, the Miracinonyx was an intermediate form between the cheetah and the puma,” says Figueirido, who stresses that its “peculiar” way of hunting “is not currently represented in nature.”

After these first two studies, researchers from the University of Malaga, Valladolid and Wisconsin-Madison want to continue this line of research based on the analysis of the complete forelimbs and the anatomy of the inner ear of the Miracinonyx, with the aim of objective of deciphering the questions that still remain to be resolved about this unique North American fossil feline. (Source: UMA)