Humans were living in a lava tube 7,000 years ago on the Arabian Peninsula

"Umm Jirsan is currently the longest reported lava tube in Arabia in terms of the horizontal length of passages, at 1481 metres [4,859 feet]," the scientists wrote in the paper published Wednesday (April 17) in the journal PLOS One.

A chemical analysis of the human remains showed an increase in certain plants, like cereals and fruits, over time — possibly because of a rise in oasis agriculture in the Bronze Age, the team said in the statement.

"The lava tube does not appear to have served as a permanent habitation location, but rather as a site that likely lay on herding routes and that allowed access to shade and water for passing herders and their animals," the authors wrote in the study.

It's possible to identify species in the rock art of Umm Jirsan, including (A) sheep; (B) goat and two stick figures with tools on their belts; (C) long-horned cattle, photo enhanced with digital software; and (D) ibex with ribbed horns and coat markings.

It is "wonderful work by this team that has made a strong reputation for excellent fieldwork and interpretation," Gary Rollefson, a professor emeritus of anthropology at Whitman College and San Diego State University, told Live Science in an email.

Anthony Sinclair, a professor of archaeological theory and method at the University of Liverpool in the U.K., said in an email that in addition to providing shelter, the lava tube also would have been a "defendable position — in terms of allowing the pastoralists to safeguard their flocks at night against local predators.