@CoachMark

I think it's over 9 feet, and would have weighed 1000+ pounds (or more?)

From the Monticello website:

Because of the animal's bulk — three times that of a lion — Jefferson called it "the Great-claw or Megalonyx.

https://www.monticello.org/research-education/thomas-jefferson-encyclopedia/megalonyx-jeffersonii-fossils/