Neanderthals ate large quantities of vegetables, a discovery made by analysis of fossilized feces. 

Researchers from the Massachusetts Institute of Technology (MIT) and the University of La Laguna in Spain carried out what may be the first major study ever made of Neanderthal diet. 

Analysis of the 50,000 year-old manure revealed that in addition to meat, these proto-humans ate tubers, nuts and berries. Researchers believe paleontologists may have placed too much emphasis on the role of meat in the diet of Neanderthals. Earlier research revealed the presence of plant matter in the teeth of Neanderthals, but that did not mean the species ate vegetables. 

"Sometimes in prehistoric societies, they used their teeth as tools, biting plants, among other things. We can't assume they were actually eating the plants based on finding microfossils in their teeth," Ainara Sistiaga, a graduate student at the University of La Laguna and visiting student at MIT, said.

El Salt, an area in Spain known for Neanderthal fossils, is home to artifacts that stretch back 50,000 years. There, researchers were able to unearth Neanderthal scat for analysis. They searched for metabolized cholesterol, which would provide evidence of meat consumption, as well as the plant-derived phytosterol. 

"Analysis of five sediment samples from different occupation floors suggests that Neanderthals predominantly consumed meat, as indicated by high coprostanol proportions, but also had significant plant intake," Sistiaga and her team wrote in an article detailing their discovery. 

After the samples were sent to the laboratory, the fossilized manure was ground into a fine powder, and treated the material with solvents to extract organic markers from the dung. 

Researchers concluded that the Neanderthal diet consisted largely of animal products, with plants and vegetables making up part of their food intake. At any given time, climate, migration and seasonal patterns could have made some foods more readily available than other sources. The hunter-gatherers likely ate what they could in their area. 

"It's important to understand all aspects of why humanity has come to dominate the planet the way it does. A lot of that has to do with improved nutrition over time," Roger Summons of MIT, and co-author of the study, stated in a press release. 

Next, the team will take soil samples from Olduvai Gorge in Tanzania, where some of the oldest human remains have been found. They hope to be able to uncover evidence of what these distant human might have eaten long ago. 

Investigation of Neanderthal poop and what it can tell us about the role of vegetables in their diet was published in the online journal Plos One.