What prehistoric poop reveals about extinct giant animals
Spores from a fungi found in megafauna poop can tell us when enormous creatures went extinct.
Looking at poop can tell us a lot. Poop offers a window into all sorts of hidden worlds: bird microbiomes, clam habitats, recovering coral forests, and more.
Excrement can also tell us about how and when animals went extinct thousands of years ago. A study published April 26 in the journal Quaternary Research looked at the fungal spores in the dung of the large animals, such as 20-foot-tall ground sloths and 1,000 pound armadillo-looking animals called armored glyptodonts, that roamed the Colombian Andes in South America during the Pleistocene.
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They found that the animals became extinct in not one, but two waves. The megafauna in this study first became locally extinct at Pantano de Monquentiva, a valley in Colombia surrounded by hills and near a bog, about 23,000 years ago and then again in the same area about 11,000 years ago.
Spores of coprophilous fungi pass through the guts of these megafauna during their life cycle. The presence of these spores in sediment samples provides evidence that these long-extinct animals lived in a certain place and time.
The team used samples found in a peat bog in Pantano de Monquentiva, about 37 miles from Bogota, Colombia. The findings offer a window back in time to better understand how the disappearance of large animals could transform ecosystems like they did all those millennia ago.
“We know that large animals such as elephants play a vital role in regulating ecosystems, for example by eating and trampling vegetation,” Dunia H. Urrego, co-author and University of Exeter biologist and geographer, said in a statement. “By analyzing samples of fungal spores, as well as pollen and charcoal, we were able to track the extinction of large animals, and the consequences of this extinction for plant abundance and fire activity.
The team found that the Monquentiva ecosystem changed dramatically when the megafauna disappeared, with different plant species thriving and increased wildfires. The analysis of the fungal spores didn’t tell exactly which large animals were present, but it’s possible that the animals were either the giant sloth and armadillo, or even macrauchenids and toxodonts, two peculiar extinct animals reminiscent of today’s camels and rhinoceroses.
[Related: Our bravest ancestors may have hunted giant sloths.]
The study also found that when all of this plentiful megafauna disappeared, it had major effects on the ecosystem. Roughly 5,000 years after their disappearance, the megafauna began to live again. This reprieve was short lived, and they all went extinct in a second wave of extinction 11,000 years ago. While the team does not know the direct causes of this, a number of factors like plant extinctions, climate changes, increased hunting by humans, and even a meteorite spike are potential causes.
“After the megafauna vanished, plant species at Monquentiva transitioned, with more woody and palatable plants (those favored by grazing animals), and the loss of plants that depend on seed dispersal by animals,” co-author and geographer also at the University of Exeter Felix Pym said in a statement. “Wildfires became more common after the megafauna extinctions – presumably because flammable plants were no longer being eaten or trampled upon.
With the planet’s current biodiversity crisis in mind, the study points to the importance of conserving local plants and watching fire activity before the value humans gain from nature completely disappears.