海洋岛屿 11

Crabs may not seem unusual

But there's one kind here that's like no other.

On this little island in Vanuatu lives a real oddity.

It's the largest terrestrial invertebrate on Earth

The robber crab.

The biggest can weigh up to four kilograms

The same as a newborn baby

And have a leg span of one meter.

It's a hermit crab on steroids.

At night, the huge "robbers" really come alive.

Although these crabs are found throughout the Pacific

It's only on undisturbed islands that you can see them in such numbers.

Exactly why robber crabs have grown so big is a mystery

But with so few creatures making it to these remote islands

The giant crustaceans seem to have filled a niche

normally taken by medium-sized mammals.