Dr Ronald Clarke

Name ID 1258

See also

Mail and Guardian
Extract Date: December 20 1999

Clarke uses chimps to prove theory

Dr Ronald Clarke used circus chimpanzees to prove his theory about the Laetoli footprints in Tanzania.




TWENTY years ago, Dr Ronald Clarke was invited by famed palaeoanthropologist Mary Leakey to continue an excavation begun at Laetoli in Tanzania.

An American chemistry professor from Rhode Island, Paul Abell, had discovered a hominid heel impression in 3,6-million-year-old volcanic tuff, or sediment formed out of volcanic ash. Subsequent excavation by Tim White of the University of California at Berkeley uncovered the first footprints of a trail made, apparently, by two individuals.

Clarke accepted Leakey's invitation -- and inadvertently entered an arena of fierce debate.

The prints were clearly made by individuals walking bipedally (upright on two legs) but Leakey and Clarke differed in their interpretations. Says Clarke, "I was struck by the fact that the prints did not seem fully human: there was separation of the big toe from the other toes, and, behind the end of the big toe, a smallish round impression that looked like a toe.

"Mary -- advised by other experts -- insisted it was Homo, and that the second of the two trails must have been made by one individual walking in another's footprints. I, on the other hand, thought the prints were [made by one creature:] ape-like with long toes -- not fully human."

Public outcry greeted Clarke when he stated his views in 1985 at the conference celebrating the 60th anniversary of the Taung discovery, and he didn't publish them. But he was not convinced he was wrong. Later that year he arranged an experiment with the Boswell Wilkie Circus in Johannesburg -- and a friendly trainer -- to coax a female and a male chimpanzee to walk next to each other bipedally over wet sand.

"The circus chimps produced prints that looked like the Laetoli footprints," Clarke recalls. "Not only did those of the male look similar -- big toe aligned with the others plus the 'apparent' toe within, caused by the imprint of a joint -- but also the female had a completely different footprint. She was more timid -- she dug her heels in and spread her big toe wide and kicked up a lot of sand -- whereas he was confident and tended to walk with his big toe most often close to the other toes.

"The circus prints showed that apes with toes capable of opening up to a wide degree can also bring that toe into alignment when they walk upright -- they are capable of doing both."

The conclusion -- in a scientific paper published this month -- is that "when the chimpanzee walked bipedally in a confident manner, it preferred to align its big toe with the others, presumably for more efficient locomotion".

The foot bones of the 3,33-million-year-old skeleton at Sterkfontein have inadvertently given Clarke a further -- perhaps clinching -- argument. Comparing the evidence of the foot bones, the footprints in Tanzania, and those made by the circus chimps, Clarke has announced: "The Laetoli footprints could [in fact] have been made by feet with slightly divergent big toes as represented by the Sterkfontein Australopithecus StW 573."

-- The Mail & Guardian, December 20 1999.

Extract ID: 3294

external link

See also

Coughlin, Kevin Were two species of early man really one?
Extract Author: Kevin Coughlin
Page Number: b
Extract Date: February 21, 2003

Were two species of early man really one?

Star-Ledger Staff

To further stir things up, Blumenschine colleagues Ron Clarke, a fossil surgeon from South Africa, and Charles Peters of the University of Georgia say other Tanzanian fossils described as Homo habilis really may be something else -- a smaller- brained species, as yet unnamed.

The process of naming species is called taxonomy, and it can produce these kinds of sparks among scientists.

"This problem is not unusual," writes South African researcher Phillip Tobias in a commentary that accompanies Blumenschine's paper in the journal Science.

"We are living at a time when hominin samples from just one or two sites are generating a flurry of new species and genera," asserted Tobias, who helped name Homo habilis in 1964. "Hominin" refers to humanlike primates.

Naming our ancestors is crucial to studying them, said Ian Tattersall, anthropology curator at the American Museum of Natural History. "You'll never understand the play if you don't know who the actors are," he said.

Tattersall welcomes Blumenschine's claims: "This will open the way for a lot of discussion. There's plenty of room for controversy."

There is room because precious little is known about Homo habilis. No complete skeletons have been found; most of what is known comes from a few dozen fragments.

Homo habilis was discovered in 1960 by a Leakey team, which unearthed a lower jaw on the eastern side of Tanzania's Olduvai Gorge, a fossil treasure trove in East Africa. Blumenschine's team made its 1995 find on the western side of this ancient lake.

Perhaps 5 feet tall, Homo habilis scavenged for food and probably sought refuge in trees, Blumenschine said.

The species' use of flaked- stone tools, for butchering fresh kills abandoned by predators, distinguished it from another cousin, Paranthropus (Australopithecus boisei).

Homo habilis also had a larger brain -- almost half the size of the modern organ, Blumenschine said.

Extract ID: 3941