Papagaios, Life & Times on a Speculative Archipelago - The Mock Rock and the Beach Octopus

Transcript of a segment of “Life in Cold Blood” episode three "Dragons of the Dry", first broadcast 18^th February 2008.

[David Attenborough sitting on a beach of dark grey and black rocks, speckled with green algae.]

This is one of the Papagaios Islands in the middle of the Atlantic Ocean. Rocky beaches like this one are found on many of the islands in the archipelago and are home to many creatures found only here.

I’m having to speak up to be heard over the squawking of seabirds. Just behind me are thousands of penguin-like birds called marquinhets that nest on these beaches. But there is another animal one screen right now and it has been right beside me this whole time.

[Attenborough leans down next to a chunky rock around 50cm long.]

At a glance this is a rock like any of the countless others on this beach. But look closer, near its base, and you can see slender toes tipped with sharp claws. Look closer still and the rock’s algae-covered surface is in fact the hardened and thickened scales of a lizard, camouflaged perfectly to blend in with its home.

The local people call it ‘rastejador de costa’ which is Portuguese for ‘coast creeper’ but English explorers in the Eighteenth and Nineteenth Centuries gave it the more direct name of ‘mock rock.’ This unusual lizard spends its entire life on the beaches, utilising its remarkable camouflage not to hide from predators, nor to sneak up on prey, rather to trick their parents. This is an egg eater.

[Footage of a creeper moving along the beach, extending surprisingly long, thin limbs then retracting them under its shoulder pads.]

Despite its bulky body it is an agile creature. It moves across the beach slowly and steadily, passing over the uneven terrain with ease. Approaching a nest, it draws in its legs, its clawed hands gripping tightly to the rock it is on. A lone marquinhet, brooding its eggs, turns to look.

This isn’t the best hiding spot. Coast creepers prefer to nestle between rocks with only their head and backs exposed. These are the parts with the best camouflage, but also the thickest armour.

[The marquinhet gets up from the nest and waddles to the creeper, peck it all over looking for a weak spot.]

The lizard’s head, back and stumpy tail are protected by a series of osteoderms, bony growths covered and connected by thick, leathery skin, similar to the armour of an armadillo. Smaller scutes fill in gaps along the face and sides and even the eyelids are armoured. The only vulnerable parts of a creepers body are along its underside, where the skin is still leathery, but unarmoured and more susceptible to injury and so this creeper will keep remain pressed against its rock until the marquinhet gives up its assault, which it eventually does.

[Marquinhet waddles back to nest to find broken egg shells]

This bird spent too long attacking the creeper and in its absence its nest has been raided anyway, though not by a lizard.

[A green-coloured octopus drags itself quickly along the rocks.]

The Papagaian beach octopus is one of several species of octopus found nowhere else in the world and unlike most of their kin, they are amphibious. Other octopuses can survive out of the water for around twenty minutes, absorbing oxygen for as long as their skin is moist, but the beach octopus has taken bolder steps.

[A beach octopus, half in a rockpool half on the rocks.]

This octopus is able to hold water inside its body, passing it over its gills again and again by contracting the muscles of the mantle cavity. This motion keeps the water in contact with the gills moving and allows far more oxygen to be extracted. As a result, the beach octopus can stay on land for over an hour if required.

[A beach octopus crawling past a marquinhet nest.]

As an intelligent animal, the beach octopus is patient and watches both the nesting birds and its rival egg-eater the creeper to find the perfect time to strike. Its one metre long tentacles help it to grab the eggs from a distance before pulling them towards its body where the beak makes short work of the eggshell.

[The octopus suddenly camouflages itself against the rocks as a pair of marquinhets waddle past on the way to the sea.]

Able to change both the colour and texture of its skin, its camouflage is far superior to that of the creeper, at the cost of being nearly defenceless if caught. Therefore, the octopus must choose its targets wisely and always be prepared for a quick getaway. In this it has the advantages of all octopuses, being able to fit its body through extraordinarily small gaps between the rocks to hide, or make short cuts on its way back to the water.

[A beach octopus slinks into a rockpool with a splash. A nearby creeper opens its eyes at the sound.]

Together the coast creeper and the beach octopus form an unlikely pair – rivals for the same food but with their own strengths and weaknesses that make their war, against both the marquinhets and each other, an ongoing one.