Footprints left by a prehistoric mother and her toddler dodging sabre-toothed cats and wolves have been unearthed in the US.
The trackway, the longest set of fossil human prints ever found, stretches for almost a mile – and dates back 13,000 years.
It tells the remarkable story of the pair’s journey as they made their way across treacherous mudflats with hungry giant predators on their tail.
An analysis found the woman was moving at a rapid pace – intermittently carrying and putting down a two-year-old child.
British and US scientists say the toddler was “tired and probably cranky” and describe the scene as “the stuff of every parent’s nightmare.”
Study co author Professor Matthew Bennett, of the University of Bournemouth, said: “Every parent knows the feeling.
“Your child is crying and wants to go home, you pick them up to comfort them and move faster, your arms tired with a long walk ahead – but you cannot stop now.”
He added: “Now add to this a slick mud surface and a range of hungry predators around you. That is the story the longest trackway of fossil footprints in the world tells us.”
They reveal the woman both taking the child to a destination – and then coming back without it.
Prof Bennett said: “Between the outward and return journeys, a sloth and a mammoth crossed the outward trackway.
“The footprints of the return journey in turn cross those animal tracks. The sloth tracks show awareness of the human passage.
“As the animal approached the trackway, it appears to have reared-up on its hind legs to catch the scent – pausing by turning and trampling the human tracks before dropping to all fours and making off.”
In contrast, the mammoth tracks, at one site made by a large bull, cross the human trackway without deviation, most likely not having noticed the humans.
Prof Bennett said: “The (region) was home to many extinct ice age animals, perhaps hunted to extinction by humans, perhaps not. Tracks of these animals helped determine the age of the trackway.
“We found the tracks of mammoths, giant sloths, sabre-toothed cats, dire wolves, bison and camels.
“The trackway tells a remarkable story. What was this individual doing alone and with a child out on the flats, moving with haste?
“Clearly it speaks to social organisation, they knew their destination and were assured of a friendly reception.
“Was the child sick? Did a rainstorm quickly come in catching a mother and child off guard? We have no way of knowing and it is easy to give way to speculation for which we have little evidence.”
The lakebed’s formerly muddy surface preserved the footprints for thousands of years as it dried up.
Co author Dr Sally Reynolds, an expert in early humans at Bournemouth, said: “This research is important in helping us understand our human ancestors, how they lived, their similarities and differences.
“We can put ourselves in the shoes, or footprints, of this person and imagine what it was like to carry a child from arm to arm as we walk across tough terrain surrounded by potentially dangerous animals.”
The footprints described in Quaternary Science Reviews were discovered at White Sands National Park in New Mexico.
The lakebed, known as a playa, contains literally hundreds of thousands dating from the end of the last ice age 11,550 years ago to sometime before 13,000 years ago.
They were notable for their straightness, as well as being repeated a few hours later on the return journey without a child in tow – which can be seen from the tracks.
Prof Bennett said: “This individual did not deviate from their course. But what is even more remarkable is that they followed their own trackway home again a few hours later.
“Each track tells a story: a slip here, a stretch there to avoid a puddle. The ground was wet and slick with mud and they were walking at speed, which would have been exhausting.
“We estimate they were walking at over 1.7 metres per second – a comfortable walking speed is about 1.2 to 1.5 metres per second on a flat dry surface.
“The tracks are quite small and were most likely made by a woman.”
The only other possibility is they belonged to an adolescent male who was returning the child to its mother.
Prof Bennett said: “At several places on the outward journey there are a series of small child tracks, made as the carrier set a child down perhaps to adjust them from hip to hip, or for a moment of rest.
“Judging by the size of the child tracks, they were made by a toddler maybe around two years old or slightly younger. The child was carried outward, but not on the return.”
He added: “What we can say is the woman is likely to have been uncomfortable on that hostile landscape, but was prepared to make the journey anyway.
“So next time you are rushing around in the supermarket with a tired child in your arms, remember that even prehistoric parents shared these emotions.”