An octopus and its coconut-carrying antics have surprised scientists.

Underwater footage reveals that the creatures scoop up halved coconut shells before scampering away with them so they can later use them as shelters.

Writing in the journal Current Biology, the team says it is the first example of tool use in octopuses.

One of the researchers, Dr Julian Finn from Australia's Museum Victoria, told BBC News: "I almost drowned laughing when I saw this the first time."

He added: "I could tell it was going to do something, but I didn't expect this - I didn't expect it would pick up the shell and run away with it."

Quick getaway

The veined octopuses (Amphioctopus marginatus) were filmed between 1999 and 2008 off the coasts of Northern Sulawesi and Bali in Indonesia. The bizarre behaviour was spotted on four occasions.
Octopus inside coconut (Roger Steene)

The octopuses use the coconuts as a shelter

The eight-armed beasts used halved coconuts that had been discarded by humans and had eventually settled in the ocean.

Dr Mark Norman, head of science at Museum Victoria, Melbourne, and one of the authors of the paper, said: "It is amazing watching them excavate one of these shells. They probe their arms down to loosen the mud, then they rotate them out."

After turning the shells so the open side faces upwards, the octopuses blow jets of mud out of the bowl before extending their arms around the shell - or if they have two halves, stacking them first, one inside the other - before stiffening their legs and tip-toeing away.

Dr Norman said: "I think it is amazing that those arms of pure muscle get turned into rigid rods so that they can run along a bit like a high-speed spider.

"It comes down to amazing dexterity and co-ordination of eight arms and several hundred suckers."

Home, sweet home

The octopuses were filmed moving up to 20m with the shells.

And their awkward gait, which the scientists describe as "stilt-walking", is surprisingly speedy, possibly because the creatures are left vulnerable to attack from predators while they scuttle away with their prized coconuts.
Veined octopus (Mark Norman)
The veined octopus is a meaty feast for predators

The octopuses eventually use the shells as a protective shelter. If they just have one half, they simply turn it over and hide underneath. But if they are lucky enough to have retrieved two halves, they assemble them back into the original closed coconut form and sneak inside.