The reptile, described by hunters as 13 feet long, sneaks up on the helpless bird in a Florida swamp and chomps down on the helpless animal, swallowing it whole.
The video, which has more than 963,000 views and 3,000 comments, has been shared more than 13,000 times on Facebook after being posted by Cass Couey.
“Alright you’re fed, now get outta here,” the man filming says.
In the background, one of the boaters can be heard saying that was “number two of the day.”
After that, another boater is heard asking where “the other one that ate the other one” is.
In separate footage, a smaller alligator is spotted devouring another duck.
Alligators can grow up to 800 pounds and 13 feet long on average.
According to the Everglades National Park, the largest alligator ever recorded measured 17 feet, 5 inches.
Richard Wilbanks, 74, was walking with his three-month-old cocker spaniel Gunner near Fort Myers when the reptile snatched the pup and dragged him into the lake.