PUBLISHED : Tuesday, 21 July, 2015,
Stephen Chen
Li Yijun, author of the paper, published in the latest issue of the journal Vertebrata Palasiatica, said it was the consistency of approach that was particularly remarkable. “It's amazing. This is like playing the Hunger Games for more than two million years without bothering to change the strategy,” he said.
The attack left a couple of teeth marks on the lower jaw of a large bull, with one fang so powerful it pierced through a bony wall as thick as 7.7mm. “At first we thought the hole was caused by a missing tooth. It was so deep, so perfect,” said Li, who made the discovery while studying for his PhD at the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.
But the teeth were complete, and further examinations ruled out the possibility of unnatural damage on the fossil found in Longdan village, Gansu province. The size and shape of the hole and dent matched "perfectly" the teeth found on big cats living in the same region around 2.4 million years ago, such as Panthera palaeosinensis, an ancestor to modern tigers. “It is a remarkable discovery. It is the earliest and may even be the only fossil evidence of a tiger bite ever reported,” said professor Deng Tao, Li’s mentor and researcher at the institute’s key laboratory of vertebrate evolution and human origins.
Modern tigers often faced “giant” prey considerably larger than heavier than themselves. Animal behaviour researchers have found that the feline predators tend to go for the prey’s head or neck.
This strategy allows them to wrestle with the prey, and with their powerful jaws and sharp teeth closed on the prey’s mouth or throat, suffocate it or cause it to bleed to death.
Though scientists could simulate an ancient predator’s attacking strategy by modelling their physical structure in computers, direct fossil evidence was rare, with similar finds only being reported for hyenas and bears, Deng explained. The location of the two million year old teeth marks shows that ancient big cats used the same attack strategy as their modern offspring, he said.
The fossil belonged to Leptobos brevicornis, an extinct bovine with sharp, pointed horns and weighing more than 300 kilograms. It is unlikely the animal died immediately after the attack because no further teeth marks could be found. But Li suspected it did not live long either as there was no sign of healing or further growth.
Li said they would carry out further study on the rare fossil to obtain more information about the attack. A major challenge was to measure the exact force of the bite by measuring the cracks inside the jaw bone, which was too large to fit into a typical CT scanner.
The scientists were also puzzled by the fossil deposit at Longdan village. In Longdan they found many more predators than prey, a phenomenon not seen in most other fossil sites. The effort to explain the mystery has been ongoing since the site was discovered in 1999.
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