Venomous Sea Snakes Mistake Human Divers for Potential 'Mates'

Scuba divers have often reported being attacked, unprovoked, by deadly Olive sea snakes. Now, however, scientists suspect these attacks might actually be the creatures' "misdirected" attempts at courtship, as they mistake the divers for possible mates.

According to Oceana, Olive sea snakes live in coral reefs in the western Pacific Ocean, spanning from Australia to New Guinea. Sometimes reaching over six feet in length, these "highly venomous" snakes "actively [hunt] small to medium sized fishes and benthic invertebrates, including prawns and crabs."

"Though they only rarely bite people, their bites have been known to be fatal," noted the organization.

Sea Snake
Observing Olive sea snakes in the Great Barrier Reef, researchers concluded "attacks" on humans were just part of the creatures' confused attempts at finding a mate. A male Olive sea snake. Jack Breedon/Scientific Reports

The new study, published in Scientific Reports last week, sheds light on the sometimes-strange behavior of these sea snakes. The serpents are known to instigate "unprovoked attacks" on humans, where the creatures "swim directly toward divers, sometimes wrapping coils around the diver's limbs and biting." However, after studying sea snake encounters in the Great Barrier Reef, researchers concluded these creatures weren't, in fact, aiming to attack humans. Rather, the incidents were just part of the creatures' confused attempts at finding a mate.

These particular "attacks"—which are not reflective of all sea snake encounters—feature the snakes performing jerky, rapid charges at divers. In these cases, they believe the "highly aroused" snake mistakes the human diver for another sea snake, either as a potential mate or a rival.

Specifically, they noticed these encounters "occurred after a courting male lost contact with a female he was pursuing, after interactions between rival males, or when a diver tried to flee from a male."

"These patterns suggest that 'attacks' by sea snakes on humans result from mistaken identity during sexual interactions," noted the study.

Also contributing to the theory is the fact that these "attacks" took place primarily during the species' breeding season, between May and August—Australia's winter months. Researchers also found that male sea snakes are far more likely to approach divers than their female counterparts.

"It's just a lovesick boy looking for a girlfriend and making a rather foolish mistake," explained researcher Dr. Richard Shine, one of the study's authors, to The New York Times.

In the rarer instances where a female sea snake rapidly approached a diver, researchers believed they were actually trying to "flee from courting males."

"In these cases, the diver likely was perceived as a potential hiding place," they noted.

The researchers, meanwhile, recognized how strange their findings might sound to outside ears.

"At first sight, the idea that a snake might mistake a human diver for another snake seems ludicrous, given the massive disparity in size and shape between those two objects," they wrote. "Nonetheless, this offers the most plausible explanation for our observations."

They added that "sea snakes may find it difficult to see clearly underwater"—a factor no doubt contributing to their confusion.

The data used in the study was collected by Tim Lynch between 1994 and 1995, after encountering sea snakes in the Great Barrier Reef, reported The Independent. Dr. Shine, meanwhile, picked up the old data and led its reanalysis.

Newsweek attempted to contact Dr. Shine for further comment.