Stephen Gustafson, 66, jumped onto the reptile in a bid to save his West Highland Terrier, Bounce.
According to Sky News, the grandfather was trimming the branches of an oak tree outside of his house when his dog was attacked.
Gustafson heard Bounce 'yelp' before spotting that the alligator had the terrier in its mouth. He said: "I saw the dog moving into the water and ran down the short hill in my backyard and just took a flying leap and landed flat on the back of the alligator."
In a tussle that Gustafson said lasted 30 seconds, the reptile snapped at the man's hand after he freed the dog. Gustafson did not get hurt in the attack.
The alligator eventually swam away from the pair but was soon trapped and preserved by Gustafson's family, who plan on keeping the animal as an "heirloom for future generations to see what their crazy great-grandfather did".
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