During the filming of the BBC’s Blue Planet 2, a team of scientists were able to use Triton submarines to venture into areas of the ocean never explored before. Descending into the “twilight zone”, an area of the deep sea between 200 and 1,000 metres deep, the group captured some amazing footage. However, there was one creature that left quite an impact on presenter Sir David Attenborough and the rest of the team.
The Histioteuthis heteropsis, also known as the Strawberry Squid, is a species of cock-eyed squid that gets its name from its unique facial features.
The cephalopods have two different kinds of eyes, one being small and blue, while the other is large and yellow.
Sir David revealed how his team first uncovered them in November 2017.
He said during the BBC documentary: “The deep ocean is as challenging to explore as space – we know more about the surface of Mars than we do about the deepest parts of our seas.
“As we descend into the deep, the pressure increases and the lights from above all but disappears.
“200 metres down, we enter an alien world – the twilight zone a sea of eternal gloom.
“Survival here means making the most of every last glimmer.”
Sir David, now 92, continued: “What we found was a squid, but this is one that only lives here.
“Its right eye looks permanently downwards, but its left eye is much bigger and trained upwards to detect the silhouettes of prey swimming nearer the surface.
“No wonder it’s nicknamed the cock-eyed squid.”
The size of its upwards-facing left eye increases its sensitivity to the faint sunlight shining down from the surface.
In the murky waters, bioluminescent creatures – like the cock-eyed squid – camouflage themselves to escape danger.
This involves masking their shadows by emitting light that matches the intensity of the downwelling surface rays.
The squid’s yellow lens, common in some species of deep-sea fish, helps it pierce through this camouflage so it can detect bioluminescent prey such as shrimp.
The right eye, on the other hand, scans the waters below for bioluminescent flashes emitted by lurking predators or prey.