American crocodiles are thought to live about 80 years. That might be correct. Or to might be completely incorrect. recently crocodile hunters in Mississippi shot and killed a specimen that weighed almost half a ton. While dressing the animal (cleaning it out, and separating the meat from the ofal), the hunters discovered nine spherical lead balls. All of them were American Civil War musket rounds and might have been fired at the animal over a century ago.
These musket balls were probably .54 caliber low velocity rounds typical fire rout of the era pattern muskets. It did not survive the .50 cal round fired by the hunters.
This croc would have to be about 185 years old.