Prehistoric footprints record battles between people and giant sloths
April 26, 2018 8:57 AM   Subscribe

Over 10,000 years ago, weapons at White Sands were aimed at giant sloths -- Pleistocene tracks record humans stalking and confronting giant ground sloths. (Kiona N. Smith for Ars Technica) Records of footprints, or ghost fossils, reveal life and death story from the ice age (Kelly Carroll for National Park Service), according to recent research at the White Sands Trackways, which may represent the largest concentration of Pleistocene trackways in the United States, where most (but not all) tracks pre-date humans in the area, which is adjacent to the White Sands Missile Range in New Mexico. (Full research article from Science Advances)

How to hunt a giant sloth – according to ancient human footprints (Matthew Robert Bennett, Professor of Environmental and Geographical Sciences, Katie Thompson, Research Associate, and Sally Christine Reynolds, Senior Lecturer in Hominin Palaeoecology, all from Bournemouth University, writing for The Conversation)
Here there are tracks of extinct giant ground sloth, of mastodon, mammoth, camel and dire wolf. These tracks are colloquially known as “ghost tracks” as they are only visible at the surface during specific weather conditions, when the salt crusts are not too thick and the ground not too wet. Careful excavation is possible in the right conditions and reveals some amazing features.

Perhaps the coolest of these is a series of human tracks that we found within the sloth prints. In our paper, produced with a large number of colleagues, we suggest that the humans stepped into the sloth prints as they stalked them for the kill. We have also identified large “flailing circles” that record the sloth rising up on its hind legs and swinging its fore legs, presumably in a defensive, sweeping motion to keep the hunters at bay. As it overbalanced, it put its knuckles and claws down to steady itself.
If you want to see these "ghost fossils" yourself, you're probably out of luck -- as noted in the above-linked article, these footprints were found at White Sands National Monument in New Mexico, US, on part of the monument that [is?] used by the military. [Yes, the key word, "is" or "was," is missing in the article as currently posted.]

And as noted in the NPS article on the trackways,
Tracks found in the monument are preserved in gypsum layers and are quite fragile. Once exposed from beneath the sand, the tracks weather rapidly. Many of the recently found tracks have already eroded and disappeared. Because they breakdown so quickly, monument staff is working with experts to develop a strategy for conservation and monitoring of the tracks. Their scientific significance underscores the need for continuing research into these incredible and rapidly vanishing natural wonders.
As of 2014, there was a collaboration between the National Park Service, U.S. Bureau of Land Management, U.S. Geological Society, and the Defense Department to document the disappearing tracks.
posted by filthy light thief (17 comments total) 32 users marked this as a favorite
 
Hot damn this is awesome
posted by bq at 9:14 AM on April 26 [3 favorites]


I couldn't picture the size of a giant ground sloth until the wiki article described it as being the size of a full grown elephant; combine that with the description of it having "wolverine-like claws" and it is very alarming.

i don't really understand how the tracks were preserved for so long in the first place and none of the articles make it clear, and the research article is a little too technical.
posted by poffin boffin at 9:17 AM on April 26 [2 favorites]


Basically every sentence of that article was awesome - ghost footprints, tracks in tracks, 6M long slothmonsters, oh my.
posted by freebird at 9:34 AM on April 26 [2 favorites]


And one of them was named "Moonwatcher"
posted by CheesesOfBrazil at 9:51 AM on April 26 [1 favorite]


i don't really understand how the tracks were preserved for so long in the first place and none of the articles make it clear

The best I found was this from the article on The Conversation, which I below the break:
It is a beautiful place, home to a huge salt playa (dry lake) known as Alkali Flat and the world’s largest gypsum dune field, made famous by numerous films including Transformers and the Book of Eli. At the height of the Ice Age it was home to a large lake (palaeo Lake Otero).

As the climate warmed, the lake shrank and its bed was eroded by the wind to create the dunes and leave salt flats that periodically pooled water. The Ice Age megafauna left tracks on these flats, as did the humans that hunted them. The tracks are remarkable in that they are only a few centimetres beneath the surface and yet have been preserved for over 10,000 years.
In other words, I think that there was salty, flat land that would occasionally get damp enough that animals and people could leave footprints that would dry out. Then they filled in with blown soil, salt and/or sand, preserving them for thousands of years.
posted by filthy light thief at 9:54 AM on April 26


I've visited White Sands a few times, and it's truly one of my favorite places on Earth.

The Park Service lets a small number of people (~20 total) back-country camp in the dunes each night. I highly recommend it. Gypsum sand dunes, yucca, bizarre population of African Oryx, the occasional stealth fighter fly-over (this happened to me). It's very much like being on a different planet. Highest recommendation.

And this Giant Sloth stuff just ups the awesome.
posted by mcstayinskool at 10:25 AM on April 26 [7 favorites]


I love how one of the explanations is "who knows, maybe they were just fucking with them."
posted by gottabefunky at 12:15 PM on April 26


The Park Service lets a small number of people (~20 total) back-country camp in the dunes each night. I highly recommend it.

With requisite caution! Seriously, the deserts do not play around with the unprepared.
posted by Abehammerb Lincoln at 2:00 PM on April 26


I love how one of the explanations is "who knows, maybe they were just fucking with them."

Rocket League BC. But with a giant sloth rather than a ball.
posted by Abehammerb Lincoln at 2:01 PM on April 26


Approaching a giant sloth in that situation would have been a dangerous undertaking, even for a hunter armed with a stone-tipped spear.

You don't fucking say? Approaching an angry cuddle bunny with just a stone-tipped spear sounds terrifying to me.
posted by Abehammerb Lincoln at 2:03 PM on April 26


i can barely approach a palmetto bug with a rolled up newspaper
posted by poffin boffin at 3:06 PM on April 26 [5 favorites]


For anyone not familiar with the Giant Sloth, there are really terrifying skeletons of them at the Museum of Natural History in NYC. They were not sleepy little fellows hanging in the trees, more like the successors of T.Rex. Those people attacking them with spears had real courage. So great that their footprints remain.
posted by mermayd at 3:22 PM on April 26 [2 favorites]


It’s been a busy month here in Alamogordo, New Mexico. First we were in the news because the pilot of the Southwest Airlines plane that lost an engine is a local girl, and now we have giant sloths. And just a few weeks ago, Ozzy and Jack Osbourne were here, and Ozzy joined our local Chamber of Commerce.

Not bad for a town that doesn’t even have a Starbucks.
posted by MexicanYenta at 7:29 PM on April 26 [1 favorite]


As an example of Giant Sloth size, here's a statue at the La Brea Tar Pits with a toy lemur on top.
posted by Katemonkey at 1:20 AM on April 27 [1 favorite]


filthy light thief is correct about how footprints like these are preserved. You also find preserved prehistoric footprints in coastal areas by the same process. People and animals walk through mud, the wind/tide/flooding dumps a load of silt on top and preserves the imprints, until erosion or scour exposes them again. On the coast, they'll be exposed for a tide or two before they get washed away. Super cool.
posted by Helga-woo at 3:15 AM on April 27 [1 favorite]


Katemonkey: As an example of Giant Sloth size, here's a statue at the La Brea Tar Pits with a toy lemur on top.

For more context, Daily Kos' Paleontology 101 (which is a thing, apparently) has an article on the sloths at the La Brea Tar Pits, including photos of the statues of the Harlan's Ground Sloth next to an adult person.
posted by filthy light thief at 8:21 AM on April 27 [1 favorite]


I love the La Brea Tar Pits
posted by bq at 1:48 PM on April 27


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