Sid the ground sloth in the Ice Age movies is adorable, a pain in the neck with his shenanigans, but pretty appealing as a character, specially with the mothering instincts exhibited in Ice Age 3. Arizona is no stranger to this Pleistocene animal. The Shasta Ground Sloth was widespread in the Western United States up until about 10,000 years ago. He found caves appealing places so it isn’t surprising that Sid explored a dinosaur cave (except that it would be impossible as dinosaurs went extinct about 65 million years before ground sloth tramped around Arizona).

How do we know sloth were here? Well, they left evidence to tell their tale. In ASM’s collection is a pile of sloth dung (poop)! (No, it doesn’t smell.) I asked curator Mike Jacobs how we know it is sloth dung and he exclaimed, “Well, they’re huge—almost as big as your head!” This particular dung is from Rampart Cave in the western Grand Canyon. Sloth used that cave over many generations; and, hence, the cave was full of it—until some careless camper left a fire burning. The fire destroyed evidence of the flora and fauna that existed in this area 10-12,000 years ago. (Yes—that’s why archaeologists examine poop—to determine the animal’s diet, which reveals the plant and animal life of the area from that time period.) “It was an incredible loss of information,” said Mike.

10-12,000 year-old sloth dung from Rampart Cave, ASM collection, photo by Jannelle Weakly

This vegetarian looked a bit like a bear and would stand on its hind legs (with its strong tail making a tripod to support him) so as to reach delicious tree leaves. The sloth populating Arizona (Nothrotheriops shastensis) was one of the smallest, weighing in at about 500 pounds and standing about 9 feet high.

I got interested in sloth because of Sid the animated sloth, but talking to Mike made Sid real. Recently I visited Kartchner Caverns and who did I run into but one of Sid’s real relatives. When the cavers explored the limestone cavern they found the bones of an 86,000 year-old ground sloth. What he was doing so far south no one really knows. The environment was quite different then the upland woodlands where they normally roamed.

So who else lived in Arizona when Sid’s relatives did? Mammoths, mastodons and sabertooth cats. While we don’t have their dung, ASM’s collection does include part of a mammoth skeleton with several spear points embedded in it—evidence of the skill of Pleistocene (Clovis) hunters. When you visit the museum be sure to look through the window to the conservation lab and see the mammoth bones (jaw bones and earth block with upper torso bones) that currently are being worked on.

Clovis projectile spear points in Mammoth atlas vertebrae (front) and next to ribs (back). Mammoth from Naco, AZ, approx 13,000 years old. ASM collection, photo by Christina Bisulca