Divers regularly report sea snake interactions involving chasing and biting, the reasons for which were previously unclear.
Now a study published in journal the Scientific Reports suggests that male sea snakes may think divers are potential rivals or mates, while female snakes think they are possible hiding places.
The study uses data collected by co-author Tim Lynch describing encounters with olive sea snakes in the Great Barrier Reef, Australia, from 1994-95.
In 74 of 158 encounters sea snakes approached Lynch, and this was more common in the May-August mating season.
During this period male sea snakes look for females and start courting them as soon as they see them, study co-author Rick Shine, professor of biological sciences at Macquarie University, Sydney, told CNN.
This largely involves flicking the female's body with his tongue to check the chemicals on her skin to make sure she is the right species and sex, added Shine.
"Then aligning his body with hers, maybe wrapping coils around her to hold her in place so he can position himself for copulation," said Shine. "But females often aren't interested, so they zoom away and hide in the coral."
Male sea snakes were more likely than females to approach divers, particularly during mating season, according to the study.
In some cases they would flick their tongue at the diver, and in 13 cases they charged at the diver. When a male sea snake charged the diver it came straight after an unsuccessful chase of a female, or following an interaction with a rival male.
Charges by females were observed after they had been chased by males, or had interacted with the diver before losing sight of him.