From The Star in South Africa:
What beast preyed on our ancestors?
August 19 2008 at 06:37AM
By Shaun Smillie
At night the thing would return.
Guided by a keen nose and a taste for flesh, it slipped into the inky black dolomite cave.
Its blinded prey were easy pickings in the dark.
A sudden scream and the thing would slink away, clamping in its jaws a creature from which one day we were to evolve.
Two-million years later, and the hunt is on to give the thing a name.
From fossils gathered across the Cradle of Humankind, to the west of Johannesburg, scientists are drawing up a list of likely suspects.
And with the assistance of new technologies and finds, the search is narrowing.
In the lineup now are a motley crew of fearsome-looking carnivores.
There might have been others.
The problem, palaeontologists point out, is that at just a metre and a bit tall, our ancestors such as Homo habilis were probably the Big Mac burgers of their day.
“We were cat food, we were not that special at that time. No armour, just meat on feet,” said Dr Hannah O’Regan, a senior research officer in the School of Biological & Earth Sciences at John Moores University in Liverpool
O’Regan studies prehistoric carnivores, and for the past couple of months has worked with material collected from several dig sites in the Cradle area.
One of the feline suspects to appear under the spotlight of her inquiry at the Transvaal Museum in Pretoria was Dinofelis.
“It was in size between a lion and a leopard. It probably ambushed its prey, used its front paws to subdue the animal while biting into its throat.”
The false sabre-toothed cat had smaller canines than Megantereon. But Megantereon might have considered puny hominids not worth the effort.
With its specialised teeth, O’Regan says some academics suspect the predator was a juvenile elephant hunter.
Palaeontologist Bob Brain first considered Dinofelis a hominid killer after years of excavating at Swartkrans.
The fossil trail made him surmise that hominids were using caves like Swartkrans as shelters. But something was killing them.
The nights were colder then, there were glacial winds and our ancestors would huddle in caves for warmth.
It is something that baboons still do today.
Into these caves crept a predator, believed Brain, and he fingered Dinofelis.
This cat, he thought, was possibly a killer exclusively of primates.
Brain’s hypotheses was that Dinofelis -using superior night vision – would stalk among the sleeping hominids and select its prey.
This happened for millennia, until one day a young female hominid turned the tables and changed the course of human destiny.
In 1984, Brain discovered at Swartkrans the earliest known example of controlled fire. The pieces of charred fossilised bone were dated to 1,2 million years. Brain believes burning branches, the result of a lightning strike, were dragged into the cave.
“We don’t know what happened then, but I like to believe it was probably a woman who first dragged fire into the cave.
“I think it would have been a woman because she is likely to have done it for the safety of the group and her children. The men I think would have been more interested in hunting,” he postulated.
With the presence of fire, predators were banished from the caves forever.
But Dinofelis now has some new circumstantial evidence in its favour, suggesting that the carnivore ate something else.
The clue lies in the ancient cat’s tooth enamel. A study took samples of tooth enamel from several prehistoric carnivores.
What the scientists were looking for were minute amounts of carbon buried in the tooth.
Stable carbon isotope analysis involves tracing two carbon isotopes through the food chain. Predators reflect the carbon isotope ratios of their prey.
“Julia Lee-Thorp’s research suggests Dinofelis preyed largely on ancestral springbok,” said Brain.
The culprit, Brain now believes, was a beast far more frightening than Dinofelis and its scimitar-shaped fangs.
This predator still takes the odd human today. The tooth enamel sample drew a match on a leopard. The carbon isotope signature of a leopard taken from Swartkrans was similar to that of hominids, suggesting it may have feasted on them.
Leopards have been around a long time, at least 3,5-million years.
And there is further significant evidence. At Swartkrans a fossilised cranium was found belonging to a young hominid.
On the cranium are two puncture marks. For decades no one was sure what had caused those marks.
Then Brain placed the lower mandible of a leopard, also found at Swartkrans, over the cranium. The two canines fitted perfectly into the holes.
“That is sort of a smoking gun,” said O’Regan.
A leopard was the killer.
Throughout the article, there is Dino felis; which I have corrected to Dinofelis.
Sahelanthropus tchadensis: here.