Shocking footage has been uploaded online showing a giant alligator calmly swimming through the water with someone's pet dog hanging lifeless in its jaws.
The pup appears to be a black Labrador wearing a bright red collar.
The location where the video was recorded is not certain, but it is thought to have been filmed in the southeastern USA, an area plagued by gator attacks on small animals.
American alligators have one of the strongest jaws in the animal kingdom, crushing their prey with up to 950kg of force.
This footage emerges just one week after a dog was savaged by one of the reptiles in Boynton Beach, Florida, leading to a state-wide call for greater care around lakes.
"Alligators are predators," biologist Lindsey Hord said. "That's what puts dogs at such great risks. A dog is just a small mammal, and they have eaten small mammals for years."
Local vets and police forces warned residents to keep a watchful eye on pets and children near any bodies of water.