Sea snake approaches to divers

Scuba-divers on tropical coral-reefs often report unprovoked “attacks” by
highly venomous Olive sea snakes (Aipysurus laevis). Snakes swim directly
towards divers, sometimes wrapping coils around the diver’s limbs and
biting. Based on a focal animal observation study of free-ranging Olive
sea snakes in the southern Great Barrier Reef, we suggest that these
“attacks” are misdirected courtship responses. Approaches to divers were
most common during the breeding season (winter) and were by males rather
than by female snakes. Males also made repeated approaches, spent more
time with the diver, and exhibited behaviours (such as coiling around a
limb) also seen during courtship. Agitated rapid approaches by males,
easily interpreted as “attacks”, often 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. Rapid approaches by females occurred when they
were being chased by males. Divers that flee from snakes may inadvertently
mimic the responses of female snakes to courtship, encouraging males to
give chase. To prevent escalation of encounters, divers should keep still
and avoid retaliation.