Bits of wood recovered from a 1.2-million-year-old tooth found at an excavation site in northern Spain indicate that the early ancestors of humans may have use a kind of toothpick, scientists say.
Toothbrushes were not around yet, if the amount of hardened tartar build-up is anything to go by, according to the study.
An analysis of the tartar has yielded information about what these early men ate and the quality of their diet.
Study leader Karen Hardy of the Catalan Institute for Research and Advanced Studies (ICREA) and the Universitat Autonoma de Barcelona in Spain says the study found they ate food raw, and that 1.2 million years ago, hominins did not use fire to prepare food.
The teeth investigated by Ms. Hardy’s team come from one of the two oldest hominin remains in Europe.
The piece of jawbone found in 2007 at the Sima del Elefante excavation site in Spain’s Atapuerca Mountains is between 1.1 million and 1.2 million years old.
Dental calculus or tartar, a form of hardened plaque, was found on all but one of the teeth examined. A minute sample of tartar from one of the teeth was removed using an ultrasonic scaler, and then analysed to recover the microfossils trapped in it.
These included several types of fibres, including tiny pieces of non-edible wood, plants and animal tissue. A scale from a butterfly’s wing and a fragment of an insect leg was also detected.
One of the two types of fungal spores recovered is similar to the modern day plant pathogen Alternaria , which is associated with asthma and hay fever.
The wood fibres come from a groove at the bottom of the tooth, called the interproximal groove, which is thought to be caused by regular toothpicking.
Previously, the oldest known example of this type of dental hygiene came from the remains of a “much younger” 49,000-year-old Neanderthal.
Some of the starch granules trapped in the tartar suggest the hominins may have eaten grass seeds. From the conifer pollen grains present, Ms. Hardy’s team deducts that the hominin lived close to a forest.
“It is plausible that these ancient grasses were ingested as food,” said Ms. Hardy.
“Grasses produce abundant seeds in a compact head, which may be conveniently chewed, especially before the seeds mature fully, dry out and scatter,” she said.
According to Ms. Hardy, the intact nature of the starch granules and the uncharred fibres found show that the hominins did not yet know how to use fire to cook raw food. The teeth examined had been worn down and showed signs of heavy use that suggest they were used to grip and chew raw materials.
The findings were published in The Science of Nature journal. — PTI
