Don't need to roll up into a ball when you can just go "hull down."

Don't need to roll up into a ball when you can just go "hull down."

Originally shared by American Museum of Natural History

Check out the armor on this Fossil Friday! This is Panochthus frenzelianus, a giant glyptodont that lived in South America, just before the extinction of the glyptodonts, at the end of the last ice age, about 30,000 years ago. Some glyptodonts grew to be over 10 feet long and may have weighed as much as a ton, including the shell. Their teeth were small and shaped like columns, with flat surfaces for grinding up plants. 
The head of most glyptodonts was armored, and could also be retracted into the shell opening; the feet and tail were protected by armor as well. These shields deterred all but the most powerful carnivores from attacking this animal fortress. 
Both armadillos and glyptodonts have a completely bony shell covering their bodies. The shells are constructed differently, however. While an armadillo is covered by parallel rows of bony bands, enabling the animal to roll up into a ball when threatened, a glyptodont’s shell was composed of thick bony rosettes fused solidly together, which meant that glyptodont’s could not roll into a ball. 
Find this fossil in the Museum’s Hall of Primitive Mammals: http://bit.ly/1Ms1NrJ