Beachgoers on Dauphin Island were in for a surprise this week when a rogue alligator was spotted in the surf.

According to Sean Powers, a marine and environmental science professor at the University of South Alabama, while it is not common for alligators to make their way into saltwater, it does happen occasionally.

"More than likely, this alligator came from the delta region," Powers said. "When we see an alligator in salty water, it is usually after large rains make the bay temporarily fresher and alligators will end up swimming further down than they thought."

Dauphin Island also tends to have more freshwater conditions due to the bay and ponds located throughout the island, according to Powers.

"I would imagine it is probably going to be more common in the spring as the rains throughout Alabama and Tennessee drain into Mobile Bay," Powers said.

Powers said similar reports are made every few years, and while it can be startling to see an alligator at the beach, they will usually move back to freshwater after a few weeks.

"Alligators can't tolerate saltwater for long, as opposed to crocodiles, which are adapted to saltwater," Powers said. "It will probably be two or three weeks before the water gets salty. It is usually after a long period of rain; one or two days of freshwater usually isn't enough to make the alligators swim down."

However, crocodiles are not native to the area, according to Powers.

“To my knowledge, the only crocodiles in the U.S. are found in south Florida,” Powers said. “A crocodile is much more aggressive and will have a more pointed snout with rows of teeth on the top and bottom jaw when their mouth is closed. An alligator only has teeth visible on the top jaw.”

As alligator populations continue to increase, Powers warns that sightings may become more common.

"Alligator populations are healthy and increasing as a direct result of management action and rebuilding those populations," Powers said. "They will explore as their habitats become more populated and they look for any new areas they can inhabit. It is perfectly natural but perfectly dangerous.”

In the event of another sighting, Powers advises beach patrons to call the Dauphin Island Sea Lab or the Division of Marine Resources if the alligator poses a threat to their safety.

"You want to be sure to stay far away from it and move away as quickly as you can. Alligators can move a lot quicker than you think, and proximity increases the threat," Powers said.

"More than anything, they pose much more of a risk than sharks. Sharks are looking for fish, and most bites are accidental, but an alligator hunts. The best way to view an alligator is with binoculars."