You can easily tell the difference between an alligator and a crocodile based on the shape of their snout: alligators have more rounded mouths, while crocodiles have longer, more narrow heads.
But if you see any massive reptile floating through a Louisiana swamp, you can be sure it’s an alligator. Only gators are native to Louisiana bayous; not crocodiles. Alligators continue to grow throughout their entire lifetime. They can live into their 50’s, and have been known to reach up to 500 lbs!