A cow’s tooth from a jawbone deliberately placed beside the entrance to Stonehenge at the Neolithic monument’s very beginning in 2995 to 2900BC could offer tantalising new evidence about how the stones were transported about 125 miles from Wales to Salisbury Plain.

Analysis of the third molar tooth showed the animal began life in Wales, adding weight to a theory that cows were used as beasts of burden in hauling the enormous stones across the country.

Since the jawbone was discovered a century ago historians have been intrigued about why it was placed there and where it had come from.

Researchers from the British Geological Survey (BGS), Cardiff University and University College London found lead isotopes revealed composition spikes during the late winter to spring, pointing to a source that was older than the metal in the rest of the tooth. This was due to the cow, during pregnancy, drawing on lead already in its skeleton to create the calf, it is thought.

That lead suggested the cow originated from an area with Palaeozoic rocks, such as the bluestones found in Wales, before moving to Stonehenge.

“It tells us that very early in its life it incorporated lead into its skeleton and that lead was from old Palaeozoic rocks, older than about 400m years old. Those types of rocks crop up primarily in Britain in Wales, which is the nearest supply, and also in the Lake District and Scotland,” said Prof Jane Evans, a BGS honorary research associate.

“Wales is the closest area from which you get those kind of lead compositions. That suggests this animal, found in Wiltshire, didn’t start life in that kind of area. It must have been grazing at some time on older rocks, and the obvious conclusion, given its Stonehenge, is that Wales is the probable origin of the cow’s early life.”

She added: “The jawbone was placed in a very specific part of the earliest ring structure of Stonehenge, which implies it was some kind of ritual, archeologists will say. So the question is, why? And then you come to the question: has this animal come with the people who were involved in the transportation of the stones, or at least the earliest migrations of the people bringing the stones, from Wales to England?’”

Until recently archeologists had found no evidence of cattle as beasts of burden in Neolithic times, but a more recent paper suggested the structure of some cattle’s feet indicated they could have been, said Evans. “It feeds into that narrative quite well.”

Even if cows were not used, associated oxen may have been. “I don’t know how long it takes to drag stones from Wales to Stonehenge, but you need to be able to feed yourself and so it’s going to be a big process. You have got to have a huge support network to do it,” said Evans.

Carbon isotopes showed the female cow’s diet changed with the seasons: woodland fodder in winter and open pasture in summer. The strontium isotopes indicated the seasonal food sources came from different geological areas, suggesting the cow either moved seasonally or that winter fodder was imported.

While the jaw was found buried at Stonehenge, what was unclear whether the cow travelled to the site alive or whether its remains were curated there, but that it was possible the animal held significance to the population during the earliest building of Stonehenge, said researchers.

Michael Parker Pearson, a professor of British later prehistory at UCL, said it was “yet more fascinating evidence for Stonehenge’s link with south-west Wales” and raised “the tantalising possibility that cattle helped to haul the stones”.

Richard Madgwick, a professor of archaeological science at Cardiff, said: “It provides unparalleled new detail on the distant origins of the animal and the arduous journey it was brought on. So often grand narratives dominate research on major archaeological sites, but this detailed biographical approach on a single animal provides a brand-new facet to the story of Stonehenge.”

While archaeologists have long known some of the stones came from the Preseli Hills in Wales, and others were from Wiltshire, one central megaliths was recently identified as from north-east Scotland.