Rare sighting of sea snakes engaged in coitus on the beach stuns reptile community

A rare sighting of sea snakes engaged in coitus on land was the last thing these women expected to see at an off lead dog beach. WATCH THE VIDEO

A rare, romantic tussle between two sea snakes was the last thing Lee-Anne Hewett expected to encounter at an off-leash dog beach this week.

Mrs Hewett, 38, of Trinity’s Beach, said she and Elaine Bertoncini, 52, were walking their dogs along a beach in Yorkeys Knob, north of Cairns, about 5pm July 5 when Ms Bertoncini almost stepped on a large snake lying about 1m from the water’s edge.

Concerned a venomous sea snake might be on a dog beach, Mrs Hewett said she posted a photo of it online to see if an expert could identify the reptile.

“I belong to a snake group on Facebook, so I posted a photo to see what type it happened to be, and then everyone (online) got really excited. … The Facebook post was getting so many likes and comments and I had no idea why,” she said.

Two sea snakes – marine file snakes – in a rare sighting on land and mating on a beach at Yorkeys Knob on Monday afternoon. Picture: Lee-Anne Hewett

Members of the Fast Snake Identification (Australia Wide) Facebook group quickly identified what the women initially thought was one large snake as two marine file snakes involved in coitus.

Ollie Sherlock wrote that the snakes were non-venomous, but it was unusual for them to be out of the water.

Blanche d’Anastasi, administrator of the Australian Sea Snakes Facebook group, confirmed the snakes were mating.

“What an exciting sighting!,” the 38-year-old Magnetic Island resident wrote.

“They eat crabs and gobies. They can be found in estuaries and mangroves, but also further out to sea.”

Lee-Anne Hewett of Trinity Beach with Penny, one of her two kelpies. She came across two file snakes mating in a rare sighting on a beach in Yorkeys Knob. Picture: Lee-Anne Hewett

Rick Shine, a biology professor at Sydney’s Macquarie University, said there were two freshwater species of file snakes and one marine species though little was known about the latter.

“The sea species tends to live in tropical waters which are often full of sharks and Irukandji, so it’s a little bit more difficult to see what’s going on in their private lives,” he said.

“To my knowledge this has never before been photographed in this marine species.

“I suspect that in the throes of romance, they’ve somehow become dislodged from whatever rock or reef they were holding on to, drifted along and washed on up on the beach.”

Prof Shine, 71, who has studied the freshwater species, said file snakes gave birth to live young in the water.

Two file snakes mating in a rare sighting on a beach in Port Douglas in 2020. Picture: Shane Down

“The middle of the year is when mating when occurs in the freshwater file snake so it’s not surprising it’s happening here as well,” he said.

Professor Shine said it was rare to see a file snake on land, let alone two on land mating.

“Presumably, the vast majority of their romantic liaisons are in the water,” he said.

He said as little was known about the species, it was possible the marine file snake only bred every few years.

But Shane Down, 58, said he had caught the species mating on camera twice last year.

The boat master and engineer, who lives on the beach in Port Douglas, said he was on the lookout for wildlife daily as he walked his 4-year-old English Staffordshire Terrier, Thresher.

He had also shared videos to the snake Facebook groups.

“When I put the photos up no one had ever seen them mating before,” he said.

“Then, I get a hold of them twice in two months which blew me away.”

Two file snakes mating in a rare sighting on a beach in Port Douglas in 2020. Picture: Shane Down

Mr Down said he came across the mating file snakes at the southern end of Four Mile Beach in July and two more again near a creek closer to the Sheraton Grand Mirage Resort in September.

Miss d’Anastasi, who is writing a PhD on Australian threatened and disappearing sea snakes, said less was known about sea snakes than their counterparts that lived on land.

“With marine snakes we have a poor understanding of the timing of their mating, what the babies do, where they go where they’re born,” she said.

“Through the Australian sea snake citizens Facebook group we’re starting to get a rare window into the secret lives of snakes.”