Skipping marsupials, shark-hunting bobcats, barnacle "monsters" – unusual beach sightings come in all guises. And now, thanks to one North Carolina beachgoer and her camera, we can add swimming rattlesnakes to the list.

While out for a solo beachside stroll on Ocracoke Island, which lies in a chain of narrow barrier islands along North Carolina's coast, Sam Corlis noticed what she thought was a large clump of seaweed in the distance. But when the clump suddenly moved, she knew she was not alone on the beach after all.

Closer inspection, and some help from the zoom lens on her camera, revealed a large timber rattlesnake slowly making its way along the sand. As Corlis filmed, the snake seemed to begin slithering in her direction before turning towards the water, through the breaking waves, and into the sea. In Corlis's words, the reptile swam off like a "pro-surfer".

Although the open water is not where you'll typically find a timber rattlesnake, these animals are pretty good swimmers – their aquatic activities, however, usually play out in freshwater lakes and ponds. That said, other pit vipers that inhabit the southeastern United States, like cottonmouths and eastern diamondback rattlesnakes, do occasionally swim in the ocean.

Now, it seems, we can add timber rattlesnakes to the list.

The reptiles can grow to an impressive size: very large specimens can reach over six feet (1.8 metres) in length. And they do well in the longevity stakes, too – in some parts of the US, they can live for decades.

Once widespread throughout North Carolina (where the reptiles are sometimes referred to as canebrake rattlesnakes), the species has suffered significant population declines due to habitat loss; today, the snakes are most likely to be found in the state's mountains or in boggy areas along the coast. They're now rare enough in the region to be considered a species of special concern.

Because timber rattlesnakes are more closely associated with forests than with the beach, many online commenters have wondered what this particular ocean adventurer was doing. And that's not an easy question to answer.

Lindsay Keener-Eck, graduate student and timber rattlesnake researcher at the University of Connecticut, says that the raised head of the snake, as well as its rapid tongue flicking, suggests the reptile may have been hunting, or tracking a small creature it had recently bitten. On the other hand, it's also possible that it was disoriented or taking evasive action, she adds. "A timber rattlesnake's first line of defence is to often stay still, in an attempt to go unnoticed. If that doesn't work, they will often leave the area."

Perhaps this timber rattlesnake, caught out in the open, decided the ocean was the safest place to be. And although we don't know how the escapade ended, the snake's strong swimming ability would have helped to ensure safe travels.

Since its posting, Corlis's video has attracted some mixed responses – including, sadly, suggestions that the snake should have been killed. But this North Carolina beachgoer has a very different opinion. "[S]ince this snake was on its turf and doing what nature told it to do, I was the one encroaching upon its territory," Corlis says.



Top header image: Scott Sanford/Flickr