Microscopic plaque on the teeth of our ancestors showed a bit of what was on the menu 1.2 million years ago. It also provides evidence of oral hygiene through toothpicking, according to a new study.  

The trace material was found in remains from a member of the genus Homo recovered in the Sima del Elefante archaeological site in northern Spain, according to the study, published this month in The Science of Nature.

The calcified and fossilized plaque between the teeth was formed by the activity of sugars energized by bacteria.

These microfossils were removed using an ultrasonic scalar. The material was analyzed using gas chromatography mass spectrometry, according to the study.

The food was all raw, from various starches and grasses that apparently grew locally, to fibrous material that appeared to be animal tendons or ligaments. Insect fragments and fungal spores were also recovered.

But also in the mix were inedible wood debris in the grooves between the teeth – which indicated the use of primitive toothpicks, they add.

“A close association between a wood fibre (sic) and an interproximal groove was first detected in a 49,000-year-old Neanderthal individual and the evidence from Sima del Elefante may also be indicative of oral hygiene activity,” they write.

More detailed studies into the fossils left by our ancestors have started to shed light on the practices of our ancestors. Earlier this year, advanced isotope analysis concluded that Neanderthals made meat approximately 80 percent of their diet.