Archaeologists have discovered the 10,000-year-old footprints of a parent and toddler in the US state of New Mexico.
Parent and child walked about a mile, close to a mammoth and a giant sloth, but they didn't seem to notice.
It could be the oldest footprints left by early humans.
The child occasionally walked along, but was carried for part of the walk, researchers at Cornell University write in
Quaternary Science Reviews
This would be visible because the small footprints show only part of the track and the larger footprints are sometimes deeper on one side than the other.
Sometimes the child walked on the left, sometimes on the right.
Parent and child walked in a straight line.
A second trace has also been found, which was probably left by the same parent.
However, no traces of a child were found on this trail.
Mammoths also walked along the route parent and child
The tracks were discovered in a now parched lake, where the tracks of mammoths, giant sloths, saber-toothed tigers and dire wolves have also been found.
The walk of parent and child would therefore have been quite dangerous.
A mammoth and sloth even traversed the walkers' route.
However, travelers seem to have had no problem with this.
Because the footprints are in a straight line, it can be seen that they did not adapt their walking pattern because of the large animals
The sloth seems to have adapted because of the presence of the humans, the mammoth just walked on unadjusted.