A team of paleontologists led by scientists from the University of Michigan (USA) and the National Museum of Natural Sciences of Madrid has analyzedtooth enamel from two species of saber-toothed cats and bear dogsfound in geological excavations near Madrid. Bear dogs had teeth similar to those of today’s dogs, but their body and movements were more similar to those of the bear.
The researchers found that the feline species – aPromegantereon ogygiathe size of a leopard and aMachairodus aphanistuslarger and with the dimensions of a lion – they lived together in a wooded area. Probablyhunted the same prey: horses and wild boars. In this habitat, the small saber-toothed cats may have used tree cover to avoid encounters with the larger ones. For its part,bear dogs hunted antelope in a more open areathat overlapped the territory of the felines but was slightly separated.
“Those three animals inhabited the same geographic area at the same time. What they did to coexist wasavoid each other and share resourcess “, explains Soledad Domingo, from the Museum of Paleontology at the University of Michigan. Their conclusions have been published in the magazineProceedings of the Royal Society B.
Millions of years before the first humans appeared, predators lived during the late Miocene period in a wooded area that had grassland segments. Large carnivores, like these animals, are rare in the fossil record mainly because herbivorous animals, which are located further down the food chain, have always outnumbered carnivores. However, Cerro de los Batallones, where they have been excavating for the past eight years, is special. Of its nine sites, two are ancient sinkholes with an abundance of carnivorous mammal bones. Agile predators, the researchers note, likely jumped into natural traps in search of “easy” prey that had become trapped.
Dental research
To arrive at their findings,researchers performed a stable carbon isotope analysis in the teeth of the animals. Using a dental drill with a diamond bit, they took dental samples from 60 specimens, including 27 saber-toothed tigers and bear dogs. The rest were vegetarians. The researchers isolated carbon from tooth enamel. They then used a mass spectrometer and measured the ratio of larger carbon-13 molecules compared to smaller carbon-12 molecules. An isotope is a version of an element that contains a different number of neutrons in its nucleus.
Carbon 12 and carbon 13 are both present in the carbon dioxide that plants absorb in photosynthesis. Different plants use isotopes in different ways, which is why they retain different amounts of the element in their fibers. When a herbivore like a plant, it leaves an isotopic signal on the bones and teeth of the animal. The signal travels through the food chain and can also be found in carnivores. “This also happens in your tooth enamel now,” said Domingo. “If we take a sample of your teeth we can have an idea of what you eat. It is a sign that remains in time.”
The evidence indicates thatboth saber tooth cats lived in the densest forest and the bear dog, Magericyon anceps , spent more time in the grasslands. The felines do not show significant differences in their stable carbon proportions. This means that they probably ate the same prey and lived in the same habitat. The article proposes the idea that smaller cats used forest cover to hide from larger species, and that the two hunted prey of different sizes.
