It turns out everything in Australia isn't trying to kill you, some have more carnal intentions. Great Barrier Reef sea snakes sometimes make swift approaches to divers that are perceived as attacks. However, a new study suggests they're usually just short-sighted males confusing the diver with a female sea snake, or females seeking shelter from male assault. The knowledge that these venomous snakes are blinded by lust rather than armed with malice could save divers from responses that make situations more dangerous than they need to be.
Dr Tim Lynch, senior research scientist at CSIRO, made regular dives on the Great Barrier Reef to study olive sea snakes (Aipysurus laevis). These snakes are highly venomous, are one of the largest marine snakes growing up to 2 meters (6.5 feet), and can be lethal when accidentally caught during fishing, finding themselves in a strange environment with no way to escape.
Although bites in the water are rare, Lynch did observe frequent cases of snakes making zigzag jerky movements towards him. However, in Scientific Reports, Lynch and co-authors argue these are not what they seem. Most approaches occurred during the May-August mating season. Moreover, males usually only came close after chasing females or conflicts with other males. Lynch thinks the short-sighted snakes couldn't tell the difference between himself and their potential mate or rival.
“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,” the authors acknowledge. “Nonetheless, this offers the most plausible explanation for our observations.”
Female approaches were rarer, and usually appeared to involve fleeing an amorous male. Females often take cover in rock crevices the males can't enter when receiving unwanted attention, and humans may look like another place to hide.
“There seems to be a lot of sexual harassment in the sea snake world,” senior author Professor Rick Shine of Macquarie University told IFLScience.
Biting attempts are usually made at reflective surfaces, such as camera lenses, where a male may think its image is a rival. Divers who don't realize this could lash out at the snakes, bringing on the bite they fear, or flee, putting themselves at risk of the bends. Shine also noted to IFLScience that male snakes are so used to chasing females that swimming away from such an approach may be particularly counter-productive for divers.
“The ocean is a dangerous place for human beings – if anything goes wrong, things can end badly. And seeing a giant sea snake hurtling towards you certainly qualifies as “something going wrong,” Shine said in a statement. “Hopefully, understanding why that snake is heading towards you – that he has mistaken you for a female of his own species – can calm your nerves and lead to a better outcome all around.”