Thursday, February 23, 2012

Making Tracks

If you go to this link, you can see a huge, searchable image of ancient elephant tracks laid across what is now a desert in the United Arab Emirates. They were made at least 6-8 million years ago, while the land was watered by a river, not the dry wasteland it is today.

According to Discover Magazine

There are many fossils of prehistoric elephants that show how their bodies evolved from smaller ancestors. But elephants are much more than just tusks and trunks. They have rich social lives, full of empathy, and their behaviours haven’t fossilised as well. We know that some elephants, like the mammoth and mastodon, spent some of their time in groups, thanks to the occasional trackways and mass graves.  But the Mleisa 1 site offers much clearer evidence.
Studying it wasn’t easy. The site is too massive to photograph from the ground, but the individual prints are too small to show up on satellite images. To accurately map the trackways, Nathan Craig from Pennsylvania State University attached a small pocket camera to a kite and snapped a set of overlapping images from above. He stitched the images together into a single large mosaic, which you can see on Gigapan. By calibrating the aerial mosaic with measurements taken on the ground, the team could study the herd’s footsteps from the air. also has an article on the elephant tracks.

One day, sometime around seven million years ago, a herd of bizarre, four-tusked elephants crossed the desert that stretched over what is now the United Arab Emirates. Thirteen of the behemoths plodded along together, perhaps moving towards one of the wide, slow rivers which nourished stands of trees in the otherwise the arid region. Sometime later, a solitary animal trudged across the herd’s path in another direction. We know all this because paleontologists have found the tracks of these massive animals.
Scientists were not the first people to wonder about the fossil footprints. The huge tracksite – which stretches over an area equivalent to seven soccer fields – had been a source of speculation among local Emirati people for years. Dinosaurs and even mythical giants were thought to have been responsible for the potholes. It wasn’t until the spring of 2001 that a resident of the area, Mubarak bin Rashid Al Mansouri, led researchers from the Abu Dhabi Islands Archaeological Survey to the immense fossil field.
Dinosaurs had not created the tracks. The snapshot of time represented by the trace fossils came from the Miocene, sometime between six and eight million years ago — all the gargantuan non-avian dinosaurs had died out over 60 million years previously. Based upon the geological context and what had been found in the area before, fossil elephants were quickly identified as the trackmakers. The site was named Mleisa 1.
If the world had had to wait for me to think of using kites to make aerial photographs of the tracks, it would have been waiting still. I think it’s the most creative use of a kite since Ben Franklin and his key.

It’s amazing what the tracks themselves can tell us about elephant behavior. Elephants travel in herds organized around a matriarch. When the males hit puberty, they set out on their own until they find another group to join. The lone tracks in this picture were made by such a male, not at the same time as those of the herd.
I’m grateful for the scientists who know how to give us these snapshots of long ago. Our lives are measured in decades rather than centuries, and we can’t run as fast as some of our fellow mammals, swim as well as fish or soar like birds, but thanks to the curiosity and inventiveness of some, we can look back over billions of years of history and see out for trillions of miles.
What could be cooler than that?

1 comment:

  1. This is cool beyond words. A bit depressing, too, with the glimpse back into a time when the desert was green...but still fascinating.