Scattered on the White Sands National Monument in New Mexico are the "ghost traces" of long-dead mammoths. Now researchers using a special type of scan have discovered other prints; they belong to ancient people who deliberately walk in the wake of mammoths.
This is a fascinating look at life about 12,000 years ago at the end of the Pleistocene era and made possible by the use of ground-penetrating radar (GPR) scans that could peek beneath the surface of the earth to reveal hidden contours below.
GPR is not a new technology – it is used to test cracks in railways and in geology and archeology – but it has not been located in this way in fossilized footprints. It promises to give scientists access to many songs and prints that are not visible to the naked eye.
These hidden records can tell us much more than who (or what) walks where: the footprint can reveal the size and gait of animals, the way humans and megafauna interact with mutual and more details about life in the last Ice Age.
"We never thought to look under footprints," says scientist Thomas Urban of Cornell University.
"But it turns out that the sludge itself has a memory that records the effects of weight and inertia on animals in a beautiful way. It gives us a way to understand the biomechanics of extinct fauna we've never had before. "
Part of the beauty of GPR technology is that it can scan below the surface without the need for excavation – the equipment just has to be dragged to the ground to make measurements. This is the equivalent of a long time ago.
Records such as this one are extremely rare, which makes these discoveries even more exciting, with 800 meters (2625 ft) of human footprints crossed with large proboscis prints found among the discovered tracks. – perhaps the Colombian mammoth ( Mammuthus colum bi ). The mammoths appear to have lurked for food or fur.
The results coincide with the analysis carried out last year by the same team.
"But there are greater consequences than this case," says Urban. "The technique could probably be applied to many other fossilized footprint sites around the world, potentially including dinosaur ones.
“We have already successfully tested the method more widely in many places in White Sands. "
With GPR available, researchers should not wait for the perfect conditions to be able to spot and analyze prints, something that is especially useful in the changing landscapes of the White Sands, but may be invaluable elsewhere .
While campsites and murder sites provide very useful information for paleontologists, knowing what humans and other animals outside of these areas have done is more difficult to understand. Survey techniques such as those used here can help.
The mammoths and giant sloths that once traveled this part of the world do not return, but the traces they leave behind can help us gather details about how they moved – and how humans follow them.  "Although we can never find the fossil remains of an animal that specifically made these tracks, we know how it moved, how big it was, how fast it went and what it was related to just by looking at the tracks, "paleontologist Lisa Buckley, who did not participate in the study," says Jean Timmons of Gizmodo. "
" One animal will leave only one skeleton, but it has the potential to leave innumerable traces throughout its life. " The study was published in Scientific Reports .