The South Pacific is a vast ocean wilderness.

Its waters are teeming with life,

from tropical coral reefs that attract the great variety to the cooler,

temperate waters that attract the great numbers.

So why is it that in the midst of all this richness

the world's largest predators

can struggle to survive in this endless blue?

Nothing brings home the challenges of surviving

in the South Pacific better than the epic true story

that inspired Moby ****. On 23rd February 1821,

a lifeboat was found drifting in the eastern Pacific.

In it lay two American whalemen,

barely alive.

Their whale ship had been sunk by an enormous sperm whale.

For a staggering three months,

these shipwrecked mariners had sailed

across four and a half thousand miles

of what may be the loneliest region on the Earth.

For these sailors,

the South Pacific had become a living hell.

So what is it about this ocean that makes survival here such a challenge?