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Can dassie dung save the planet?

Published Apr 10, 2006


By Shaun Smillie

Poo poo it all you like, but academics believe fossilised dung could be paleontology's next big thing.

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Scientists across the world are turning to ancient faeces - or, as they are known scientifically, coprolites - for answers about the past.

What they are finding is causing a stink.

In the United States a 1 000-year-old coprolite revealed what was on the menu of a chilling feast, while in South Africa a botanist believes prehistoric hyena and dassie dung could one day help save the world.

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Coprolites come in all shapes, sizes and colours, the oldest date back millions of years, and are relics from when dinosaurs walked the planet.

The heaviest coprolite ever found was a 0,5m-long, "dump" left by a Tyrannosaurus rex. It weighed in at 7kg.

But not all coprolites are fossilised, or as old.

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The droppings that Professor Louis Scott, of the department of Plant Sciences at the University of the Orange Free State, is interested in have yet to turn to stone; at 40 000 years old, in paleontological terms, they are still relatively fresh.

Scott believes that what he could learn from the age-old latrines of animals like hyenas and dassies, could one day help scientists understand global warming.

"By understanding what the earth's climate was like thousands of years ago, we can maybe predict what is going to happen to the planet," Scott explained.

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Scott's aim is to work out what South Africa's prehistoric climate was like and to do this he needs to find out what vegetation was like around at the time.

He uses pollen as his guide - and Scott finds his pollen by sifting through ancient hyena and dassie excrement.

"Coprolites are good traps of pollen, they seal the pollen off from the environment and prevent it from becoming oxidised. Sometimes the pollen even has its DNA intact," he explained.

The pollen finds its way into hyena dung through the carnivore's diet and from the air it breathes: "Hyena would have picked up pollen from a wide spectrum of sources. From the meat they ate, also from their fur. Pollen is like a dust, it gets on to everything."

Finding suitable dung can be dangerous work that requires a lot of prospecting and a bit of luck.

The prize is anything over the age of 40 000 years.

"You often have to climb to rock shelters to collect the coprolites. Then you find something that looks promising, you take it back for radio carbon dating. Often the dates come back and you find that the sample is too young. You can never tell," said Scott.

What the pollen has revealed to Scott is that South Africa's climate 50 000 years ago was cold.

The world was in the grips of an ice age and sub-Saharan Africa was far drier than it is today.

"The vegetation then was what you see in the Drakensberg and Lesotho: it was grasslands and very open," said Scott.

Living in such an environment was hard, and archaeologists have found little evidence of human occupation for the period.

The oldest coprolites Scott has found were in Namibia... they were 47 000 years old.

Coprolites are probably the only way that scientists will be able to find out anything about Namibia's ancient climate.

Scott explained: "In North America and Europe most pollen is found in the remains of ancient lakes. The problem with Namibia is that there are no lakes where pollen can be extracted. Not a lot is known about the ancient climate of Namibia. But by studying the pollen found in coprolites, then we can change that."

But there are more to coprolites than pollen samples - they in fact hold a treasure trove of other information. For one, scientists are getting a glimpse of what long-extinct animals had for dinner the day before.

Shards of bone found in a coprolite left by a T-Rex has allowed scientists to hypothesis that the reptile chewed its food rather than swallowed it whole.

Some dinosaur dung contain small tunnels - tracks left by prehistoric dung beetles.

Here in South Africa academics are looking at the possibility of analysing prehistoric carnivore dung. There is the hope that some of this dung might even hold the fossilised remains of our ancestors.

The toilets of our ancestors have also not escaped the scrutiny of some academics.

It was what was discovered in the ashes of a 950-year-old hearth in a Puebloan Indian archaelogical site, in Colorado, in the United States, that provided a glimpse into of one of man's darker moments.

Archaeologists found a human coprolite in the hearth; as it was unburnt they decided to test it.

What they found were traces of human myoglobin, an oxygen-carrying protein that is only found in muscle.

Myoglobin does not occur in the intestinal tract, so the verdict was that the person who had left the coprolite had dined on human flesh, probably 24 hours earlier.

The meal was probably prepared in a nearby pot that also tested positive for myoglobin.

Not all of ancient man's meals were as controversial.

One 9 000-year-old coprolite found at the back of the Hinds Cave in Texas proved that one prehistoric individual knew all about having variety in one's diet.

The coprolite contained evidence of pronghorn antelope, cottontail rabbit, packrat and squirrels.

As for greens, the same coprolite had the remains of eight species of wild plants.

The ancient humble turd may even one day go further and expose the holy grail of human evolution - speech.

Geneticists believe that a gene called FOZP2 might be necessary for the jaw movements needed for speech.

If the gene happens to be found in 50 000 year old Neanderthal coprolites, it might prove that our bigger, often thought to be stupider, cousins had the power of speech.

All could be revealed by a bowel movement that happened aeons ago.

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