HUMAN INTERACTION WITH GIANT GROUND SLOTHS:

Artist's rendition of human interacting with a Giant Ground Sloth. Image from www.extinctanimals.org.

One of the iconic megafauna of the Paleolithic period is the Giant Ground Sloth with more than a dozen related species of Giant Ground Sloths distributed throughout North and South America. Ground Sloths ranged in size from small, just a few pounds, to the truly giant Megatherium. Interest in Megatherium began centuries ago, President Thomas Jefferson had tasked Lewis and Clark to attempt to locate them in the West on their journey of exploration.

Human with Giant Ground Sloth skeleton. Internet image, public domain.

“Megalonyx, which means ‘giant claw’, was a widespread North American genus that lived past the close of the last Wisconsin glaciations, when so many large mammals died out. Remains have been found as far north as Alaska and the Yukon. Ongoing excavations at Tarkio Valley in southwestern Iowa may reveal something of the familial life of Megalonyx. An adult was found in direct association with two juveniles of different ages, suggesting that adults cared for young of different generations. The earliest known North American Megalonychid, Pliometanastes protistus, lived in the southern U.S. about 9 million years ago and is believed to have been the predecessor on Megalonyx. Several species of Megalonyx have been named; in fact it has been stated that ‘nearly every good specimen has been described as a different species.’ A broader perspective on the group, accounting for age, sex, individual and geographic differences, indicates that only three species are valid (M. leptostomus, M. wheatleyi, and M. jeffersonii) in the late Pliocene and Pleistocene of North America, although work by McDonald lists five species. Jefferson’s ground sloth has a special place in modern paleontology, for Thomas Jefferson’s letter on Megalonyx, read before the American Philosophical Society of Philadelphia in August 1796, marked the beginning of vertebrate paleontology in North America. When Lewis and Clark set out, Jefferson instructed Meriwether Lewis to keep an eye out for ground sloths. He was hoping they would find some living in the Western range. Megalonyx jeffersonii was appropriately named after Thomas Jefferson.” (Wikipedia)

"The earliest megatherid in North America was Eremotherium eomigrans whish arrived 2.2 million years ago, after crossing the recently formed Panamanian land bridge. With more than five tons in weight, 6 meters in length, and able to reach as high as 17 feet (5.2 m), it was larger than an African bush elephant bull. Unlike relatives, this species retained a plesiomorphic extra claw. While other species of Eremotherium had four fingers with only two or three claws, E. eomigrans had five fingers, four of them with claws up to nearly a foot long." (Wikipedia)

We now have a number of lines of proof of human interaction with Giant Ground Sloths. Speaking on the PBS Newshour about the recent discovery of Paleolithic footprints at White Sands of both animals (including megafauna) and humans, David Bustos of White Sands National Park stated "We were brushing out a set of sloth prints, and Matthew found the human pring right iside the middle of the sloth print. And that's sort of sealed the deal, Oh, yes, you definitely have the megafauna and humans together. So that's sort of where the the human side of the story all began." (Sy and Jackson 2022)  

"A human footprint is shown above with a raised heel mark inside the larger, curved footprint of a giant sloth. Below, researchers mapped the sloth and human tracks to re-create the chase scene, with 'flailing circles' to mark where the the animal reared up on two feet to defend itself."  Illustration from Garisto, 2018.

"Tests of sediment showed the sloth and human prints were made at the same time. An analysis of the track also suggested the two species were interacting with one another. 'We're getting a view into the past, of an interaction between two species,' says Sally Reynolds, a paleontologist at Bournemouth University in Poole, England. ' This was a moment of action, a moment of drama.' Raynolds, Bustos and their colleagues reconstructed the chase. Humans stalked a sloth, of several sloths, which the hunters surrounded in the open. At seven places, a sloth reared up on its hind legs - towering over the humans - to fendd off an attack. But the chase continued, with the humans in hot pursuit. The encounter 'wasn't luck or happenstance; it was cold calculation,' Reynolds says. 'Our intention was to kill them.' The trail of footprints ends, though, and it's not clear who came out victorious." (Garisto 2018) This would have been a windfall of food for the Paleolithic hunters, although difficult to procure.

So, we now have evidence of humans tracking and hunting Giant Ground Sloths, is there any other evidence of interactions? "The Santa Elina rock shelter in Central Brazil shows evidence of successive human settlements from around the last glacial maximum (LGM) to the Early Holocene. Two Pleistocene archaeological layers include rich lithic industry associated with remains of the extinct giant ground sloth Glossotherium phoenesis. The remains include thousands of osteoderms (i.e. dermal bones), three of which were human modified." (Pansani et al. 2023)

Giant Ground Sloth osteoderms drilled and polished for use as adornment. Images from Pansani et al., 2023.

In this case the term modified means holes drilled in the osteoderms, apparently for use as jewelry. The modifications include the drilling of the holes as well as polishing. "We document the smoothing of the surface; traces of stone tool interaction with bone, including incisions and scars, scraping marks, scratches, percussion notches; polish and gloss; use-wear smoothing of the rim and the attachment systems. - Unmodified mylodontid osteoderms show a naturally rough external surface, notably different from the smooth polished surfaces of the three human-modified osteoderms. Among the thousands of fossil osteoderms on the site, the perforated and polished state of the three osteoderms studied here is exceptional." (Pansani et al. 2023)

So now, in addition to apparent hunting of Giant Ground Sloths by early human inhabitants, we have the use of parts of the animal for adornment. 

Panel and close-up of the image from La Lindosa, Colombia of what is assumed to represent an adult and juvenile Giant Ground Sloth interacting with humans. Online image, public domain.

My final example of human interaction with Giant Ground Sloths comes from a painted cliff in Colombia. Among the recently recorded pictographs at the remarkable site of La Lindosa in Columbia is a figure that has been identified as a Giant Ground Sloth. "The animal is accompanied by an offspring and surrounded by animated miniature men, some of whom extend their arms towards the painting. The relationship of the animal with the men appears to be central to the artist's message." (Irarte et al. 2020) This could almost be considered a visual illustration of the interactions recorded at the White Sands track site of human interaction with one or more ground sloths. Identification of this animal as a Giant Ground Sloth is apparently based on body and head shape, the relative length of front and rear legs, and an emphasis on the toes and claws projecting from the feet. It is being shown with an offspring is reminiscent of the Iowa discovery of an adult skeleton with two juveniles referenced above from Wikipedia.

Given the size of these creatures, and the length of their claws, they would have been formidable prey for early human residents in the New World.

NOTE 1: Some images in this posting were retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them. For further information on these reports you should read the original reports at the sites listed below.

NOTE 2: I have recollections in the past of having seen a photograph of a petroglyph of an animal in Brazil somewhere that had been identified as a Giant Ground Sloth. But, apologies, I have been unable to relocate it. If anyone knows of such a picture please share it with me for posting on RockArtBlog.

REFERENCES:

Garisto, Dan, 2018. Footprints prove humans hunted giant sloths during the Ice Age, 25 April 2018, https://www.sciencenews.org. Accessed online 3 January 2024.

Irarte, Jose, et al., 2022, Ice Age megafauna rock art in the Columbian Amazon?, Philosophical Transactions of the Royal Society B, https://doi.org/10.1098/rstb.2020.0496.

Pansani, Thais R. et al., 2023, Evidence of artefacts made of giant sloth bones in central Brazil around the last glacial maximum, Published online by Royal Society Publishing, 12 July 2023, DOI:10.1098/rspb.2023.0316. Accessed online 20 Novmeber 2023.

Sy, Stephanie, and Lena I. Jackson, 2022, Ancient Footprints in New Mexico raise questions about when humans inhabited North America, 4 April 2022, PBS Newshour, https://www.pbs.org/newshour/show/ancient-footprints-in-new-mexico-raise-questions-about-when-humans-inhabited-north-america#transcript. Accessed online 9 February 2024.