Shasta Ground Sloth: Mega Pooper

The extinct ground sloths are related to the smaller living tree sloths found in Central and South America. There are currently six species of sloths living today. Fossils of ground sloths are only known from the Americas, including some islands in the Caribbean, and they went extinct near the end of the Pleistocene. During the late Pleistocene at least four species of ground sloths species occurred in North America with the largest ground sloths reaching 20 feet in length and estimated to have weighed more than 3 tons. The Shasta Ground Sloth was a smaller species of sloth, reaching 9 feet in length and weighing approximately 550 lbs. The Shasta Ground Sloth lived primarily in the American Southwest, but fossils of this species have also been found in Florida.



By studying the fossil poop (coprolites) of Shasta Ground Sloths, we know that these sloths ate various kinds of plants, including cacti, yucca, and desert globemallow. This sloth may have also played an important role in the distribution of such plants such as the Joshua tree (Yucca brevifolia), as seeds of this plant is commonly found in their coprolites. Rampart Cave is particularly famous for the large number of Shasta Ground Sloth coprolites found inside. At least two dense layers of sloth dung are recognized at Rampart Cave, with the depth in some sections of the cave reaching 20 feet deep. The oldest sloth dung layer was dated between 40,000 to 24, 000 years ago and the youngest layer between 13,000 and 11,000 years ago. This suggests that there were at least two separate periods of sloths using the cave. Unfortunately, the Rampart Cave sloth dung was almost completely destroyed in 1976 by a fire that burned for many months. A large gate now covers the cave to keep vandals out and prevent further damage.