Peaceful coexistence between people and deadly wildlife: why are recreational users of the ocean so rarely bitten by sea snakes?

1) Research on interactions between humans and deadly snakes has
focused on situations that result in high rates of snakebite; but we can
also learn from cases where snakes and people coexist peacefully. For
example, coastal bays near Noumea, in the Pacific archipelago of New
Caledonia, are used by thousands of tourists and snakes, but bites are
rare. 2) Our long-term studies clarify reasons for this coexistence.
Although 97% of snakes encountered in standardized snorkel surveys were a
harmless species (Emydocephalus annulatus), we recorded dangerously
venomous taxa often enough (one snake per eight hours snorkelling) that we
would expect many risky human- snake interactions in these crowded bays.
However, the risk is reduced by low overlap between humans and snakes in
the timing of activity, both seasonally and on the diel cycle.
Mate-searching male snakes, the group most likely to approach divers,
enter the bays only in cooler months of the year when few beach users are
present. Also, snakes tend to be active by night whereas people are not.
3) Risk is further reduced by spatial divergence: bare-footed beach users
stay in sandy areas rather than the adjacent coral-reef areas that are
preferred by snakes. The response of snakes to disturbance is important
also: most sea snakes are reluctant to bite even when harassed. Water
currents frequently push sea snakes against hard objects, perhaps
explaining why the snakes do not interpret brief contact with a human as
an attack. The ability of snakes to flee is increased by uniformly high
body temperature, and a complex three-dimensional aquatic environment. 4)
Thus, the danger of snakebite for recreational users of these popular
beaches is reduced by aspects of human and snake behaviour that (i)
decrease encounter rates, and (ii) render snakes unlikely to bite even if
contacted. The risk to snakes is also reduced, because snakes are more
difficult to detect and kill underwater than on land. As a result,
thousands of snakes and people coexist harmoniously within these
small bays.