A human toddler and a mammoth crossed paths in old New...

Someone – maybe a youth, maybe someone older – rushed over the edge of Lake Otero and slipped while walking, but kept moving forward. There is evidence that this person carried a child around the age of 3 and dropped the child off in at least three different locations in the trip for at least a moment before continuing.

While that person was gone, a giant proboscidean – a Colombian mammoth or mastodon – trampled this path and stepped on a few footprints. In fact, three Proboscideans may have moved through this landscape, crossing the tracks that humans had left.

The time is hard to tell, but at another point a giant ground sloth made its way near Lake Otero. His footprints indicate a determined human awareness – a change in behavior – that may have involved getting up on two feet to smell the air, check his own safety, and determine what is ahead of him before leaving quickly changes direction and away.

The same person (or maybe a different person) went back next to the original track at some point later, but the footprints indicate they were no longer wearing anything. If the same person came back from where they came from, the child may have been left behind.

Described in a notable article published in Quaternary Science Reviews earlier this month, these scenes interpret actions taken by humans and other animals who lived in what is now New Mexico at least 10,000 years ago. Today this area is the White Sands National Park.

Many people know it for the dramatic white sand dunes that gave rise to its name, but paleontologists recognize White Sands National Park for the incredible wealth of Ichno fossils – in this case, fossil footprints – it preserves. And while many of these footprints are easy to spot with the naked eye, it is White Sand’s unique “ghost tracks” that make the place even more unique.

A section of the double track. There and back trips follow one another. Central control panel: sub-titles. Left panel: One of the tracks with little slip. (Image: Matthew Bennett, Bournemouth University)

David Bustos, manager of the Resource Program at White Sands and co-author of this recently published paper, laughed as he remembered taking scientists to an area he knew for sure contained fossil footprints for theirs Arrival to be found completely invisible. The environmental conditions, he told Gizmodo over the phone, have to be just right for them to appear: not too dry and not too wet. Their great visibility one day and their complete absence the next day have led people to refer to these ego fossils as ghost traces. This disappearing and reappearing act occurs again and again throughout the park.

During the Pleistocene, White Sands was home to a huge lake, now known as Lake Otero. There is evidence that it did not always exist as a body of water, but as many smaller lakes that formed a much larger unit when flooded. There are so many footprints around this paleo lake. Here footprints of proboscideans, giant ground sloths, canids, bison, camels, felids and humans have been discovered, sometimes in connection with each other.

“We have about 80,000 acres of Lake Otero in the park,” explained Bustos. “And on these 80,000 acres, we find fossil prints everywhere. I think that’s so incredible. And they cover long distances. Because they are so long, you can see interactions that you cannot see on other tracks from around the world. ”

This track described in the new publication extends for 1.5 kilometers, other tracks, for example one from an extinct species of camel, extend for more than 3 kilometers. The length and number of these tracks offer incomparable glimpses into ancient life.

Bustos, lead author Matthew Bennett, and co-author Sally Reynolds were part of the team that in 2018 described the phenomenal interaction between a giant ground sloth and multiple humans, with footprints indicating the sloth was being pursued and possibly mocked by the group.

Another 2019 article described the technology used to explore many of the trails, as well as another trail where an old man and a Proboscidean, perhaps a Colombian mammoth, walked in the same area, following in each other’s footsteps kicked.

Bustos has been with White Sands for 15 years. When you talk to him you have two very strong impressions: he is remarkably grateful to the scientists who worked in the park, and he really knows those footprints and the stories they might tell.

“If you can find one set of prints, you can usually find the others in the same area,” said Bustos. “And that’s the people, the mammoths, the giant ground sloth and the camel. These four are very common among the 80,000 [acres]. This is important because they were formed under the same conditions and in the same time frame. We have human and megafauna prints made of clay, sand and dolomite depending on where you are in the lake. ”

Those of us who are not around White Sands have a somewhat narrow view of what the park entails. Every new paper brings wondrous surprises and fascinating details. But Bustos has observed some of these behaviors in other places and knows so much more about the types of ego fossils that are contained in the park.

“What we often see are giant ground sloths that change their movements in response to humans. You will get up. And they will turn around. We have several in other locations in the park. Whenever there are people [prints] a sloth [the sloth will] Start going around in circles or doing fun things. But when there are no people [tracks] Present that [sloths] just meander around and walk in straight lines. They don’t spin in circles or spin. It’s very interesting. The mammoths, “he said, chuckling,” don’t seem to care one way or another. ”

Paleontologist Melissa Macias also noticed this aspect when reviewing this latest paper. “The mammoth just didn’t care and just kept walking,” she said over the phone to Gizmodo. “But the sloth turned. That says so much about the behavior of these animals. ”

Three species of ancient sloths are known from this time and geographic region: Megalonyx, Nothrotheriops, and Paramylodon. But of the three only two – Nothrotheriops and Paramylodon – have a pedolateral foot, which means they walked by putting most of their weight on the sides of their feet. The authors suggest that Paramylodon is the most likely tracer in this particular case, and of the three, it is the largest type. Some appreciate that Paramylodon was about ten feet long and could weigh up to or more than a ton. Nothrotheriops, by comparison was a slightly smaller giant ground sloth that weighed perhaps a quarter of a ton.

Macias suggested that the smaller ones Nothrotheriops Perhaps he was more afraid of people and avoided them altogether, which might explain the lack of people and people Nothrotheriops prints together. “We may never know,” she said.

The interpretation of these tracks is the domain of Matthew Bennett of Bournemouth University, who worked on footprints for most of his career and developed DigTrace, software for analyzing tracks. Scientists have examined fossil footprints using ground penetrating radar as well as 2D and 3D analysis.

“A geologist has to use what he has,” Bennett wrote in an email to Gizmodo, “but it is wrong to draw conclusions and make firm predictions from just a few tracks.” It takes a lot to get a person right to characterize. ”

This research has helped them understand how fast the person was walking, how old they might have been, whether or not they were carrying a child, how old the child was, and at what relative point in time those human footprints were cut by the ancient megafauna . It is the length of the track that provides so much valuable data.

Ashleigh Wiseman, a postdoctoral fellow at the Royal Veterinary College in the UK, helped contextualize and analyze the data for this paper, and provided information about whether the trackmaker was carrying a child.

“It was very exciting to see the toddler-sized footprints,” Wiseman said in an email to Gizmodo. “In particular, he knew that shortly afterwards, the tracks were cut by mammoth and giant ground sloth tracks. Getting an insight into the mega-faunal interactions with people over 13,000 years ago was extraordinary. ”

“For Sally and me, the trackway has a very personal dimension,” wrote Bennett, referring to co-author (and co-parent) Reynolds. “I worked on it when Sally was at home with our daughter during the early stages of pregnancy. In fact, I saw my first scan image when I dug up the trail. Because of this, we’ve long called the trackway “Zoe’s Trail,” and it’s the informal name the team now uses for the kid’s trail … Scientists shouldn’t have personal connections with science, but this piece does. ”

When asked if this latest paper and all papers since 2018 are just the tip of the iceberg, Bustos said, “Yes. There are so many more stories we would like to share and I am sure there are so many more [are] still to say. ”

These papers could be considered chapter one of the book on the white sands of old, and we are all waiting with bated breath for the next issue.

Jeanne Timmons (@mostlymammoths) is a New Hampshire freelance writer who blogs about paleontology and archeology at mostlymammoths.wordpress.com.