Here’s a giant ground sloth skeleton, unearthed from the modern state of Missouri. Sloths like this would have stood up to ten feet tall, which was typical of many of the enormous charismatic vertebrates that populated our planet up until the great megafaunal extinction which killed most of them off in the Late Pleistocene, about 12,000 years ago.
Scientists are debating the extent to which humans versus climate change caused the die-off, but the effects were far reaching, and not just because it would be amazing to have a planet with giant ground sloths (they were herbivores, btw). The actual soil composition of the planet was changed because of such creatures.
As a 2016 article in the Proceedings of the National Academy of Science USA entitled “Global nutrient transport in a world of giants” suggests, large animals tend to travel farther across land than many other animals, and the type of excrement they produce disproportionately affects the movement of nutrients across the soil. Without the megafauna, the authors of the study estimate, the most variated nutrients in soil tend to concentrate. These authors argue that the transfer of nutrients on land because of animal scat has declined to only about 8% of what it once was.
We of course rely on modern fertilizers to grow most of the plants we eat today, but continuing to generate diversity in soil will be a problem for future generations.
Sources: Sloth from Ancient Ozarks Natural History Museum, phot credit Tim Sharp
