Sea snakes.
At one time, these snakes' ancestors lived on dry land.
They must still visit the surface to breathe.
But they are beautifully adapted to life at sea...
hunting for fish around the island reefs.
They have some of the most toxic venom
of any animal, so, they don't have many predators.
But as they forage off the coast of one small island...
their greatest nemesis is approaching.
Yoko and Setsuko are hunters and they have a fearsome reputation.
These two 70-year-olds are on a shopping trip like no other.
Yoko and Setsuko live on the tiny island of Kudaka.
It's only four kilometres across and, with limited space on land,
the locals look to the sea to provide.
As the sun sets, the ladies' prey is approaching.
On certain summer nights,
venomous sea snakes move towards the island
and gather in coastal caves...
looking for shelter and fresh water to drink.
But coming ashore on this island, is extremely risky.
It takes some nerve to wade in with no protective clothing.
Sea snake venom can be ten times more powerful than a rattlesnake's.
Yoko has been hunting snakes for 40 years.
It's a skill that's been passed down the generations here,
for at least five centuries.