Researchers say they've found evidence that ancient human relatives used toothpicks.
Wood fibers were found on a tooth in a 1.2-million-year-old hominin jawbone discovered at an excavation in northern Spain. The fibers were found in a groove at the bottom of the tooth, suggesting they came from regular tooth picking.
Previously, the oldest known example of this type of dental cleaning was from the 49,000-year-old remains of a Neanderthal.
The researchers also found tartar (hardened plaque) on all the teeth in the jawbone except one. An analysis of the tartar revealed that these ancient people ate a balanced diet of meat and starchy foods, and ate their food raw.
The study appeared recently in the journal The Science of Nature (Naturwissenschaften).
Some of the starch granules found in the tartar suggest that grass seeds may have been part of the hominin's diet.
"It is plausible that these ancient grasses were ingested as food. Grasses produce abundant seeds in a compact head, which may be conveniently chewed, especially before the seeds mature fully, dry out and scatter," said study leader Karen Hardy. She's with the Catalan Institute for Research and Advanced Studies and the Universtat Autonoma de Barcelona in Spain.
The tartar also contained conifer pollen grains, suggesting that the hominin lived near a forest.
The intact starch granules and uncharred fibers found on the teeth show that these hominins did not know how to use fire to cook food. Also, the teeth were worn down and had signs of heavy use, suggesting they were used to grip and chew raw materials, the researchers said.
"Our evidence for the consumption of at least two different starchy plants, in addition to the direct evidence for consumption of meat and of plant-based raw materials suggests that this very early European hominin population had a detailed understanding of its surroundings and a broad diet," Hardy said in a journal news release.
Explore further: Raw foodies: Europe's earliest humans did not use fire
Karen Hardy et al. Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe's oldest hominin at Sima del Elefante, Spain, The Science of Nature (2016). DOI: 10.1007/s00114-016-1420-x