Study Reveals Cohabitation of Saber-Toothed Cats and Bear Dogs

A team of paleontologists have analyzed the fossilized fangs of saber-toothed cats and a bear dog to determine how these extinct mammals shared habitat and food with other large predators some 9 million years ago.

The paleontologists from the University of Michigan and the Museo Nacional de Ciencias Naturales in Madrid studied the tooth enamel of two of the species unearthed in geological pits near Madrid. They noticed that the bear dogs, which are extinct, displayed teeth that were very similar to dogs.

The researchers noticed that the cat species, a leopard-sized promegantereon ogyia and a much larger, lion-sized Machairodus aphanistus inhabited a common woodland and hunted similar prey like wild boars and horses.

Based on the habitat they predicted that the smaller saber-toothed cats may have used tree-cover to camouflage themselves against larger predators. The dogs hunted in a larger area and did  not encroach on the cats' territories much.

 "These three animals were sympatric -- they inhabited the same geographic area at the same time. What they did to coexist was to avoid each other and partition the resources," said Soledad Domingo, a postdoctoral fellow at the U-M Museum of Paleontology and the first author of the paper.

Cerro de los Batallones, where Domingo has been excavating for the past eight years, is special. Of its nine sites, two are ancient pits with an abundance of meat-eating mammal bones. 

"These sites offer a unique window to understand life in the past," Domingo said.

The researchers conducted a carbon isotope analysis on 69 specimens, including 27 saber-toothed cats and bear dogs.  They then isolated the carbon from the tooth enamel and with the help of a mass spectrometer they measured the ratio of carbon 13 molecules to that of carbon 12. The carbons are a part of the photosynthesis process.

"This would be the same in your tooth enamel today," Domingo said. "If we sampled them, we could have an idea of what you eat. It's a signature that remains through time."

The researchers were able to explain the habitat of the animals though not what they consumed, through the study.

"The three largest mammalian predators captured prey in different portions of the habitat, as do coexisting large predators today. So even though none of the species in this 9-million year old ecosystem are still alive today (some of their descendants are), we found evidence for similar ecological interactions as in modern ecosystems," said Catherine Badgley, co-author of the new study and assistant professor of ecology and evolutionary biology.

The paper is titled "Resource partitioning among top predators in the Miocene food web" was published in the Nov. 7 edition of Proceedings of the Royal Society B.