Life in the Dark: Episode 3

Sir David Attenborough looks at the eyes of squid and owls and how they've managed to maximise their vision.

Life in the Dark

Sir David Attenborough continues to shine the spotlight on nature's most amazing animals this time looking at the vision in squid and owls. Perhaps not a classic pairing, both owls and squid have incredible adaptations for being able to navigate at night.

Attenborough on Giant Squid

Attenborough on Giant Squid

Giant Squid

The giant squid has one of the biggest eyes in the natural world, rivalled only by that of the related colossal squid. But why does it need it?

This huge eye, with an incredibly large pupil allows this near-mythical creature to pick up what little light there is in the pitch black of the deepest parts of the world's oceans.

Light struggles to penetrate to the depths that the giant squid roams, as such it has been suggested that its main use might be to pick up the faint twinkle of bioluminescence: evidence of prey species or other individuals. It could even signal the start of one of the greatest unrecorded battles on our planet: that of the giant squid and the predating sperm whale.

Attenborough on Owls

Attenborough on Owls

Owls

The owl's huge, over-sized eyes are so big they are unable move in their sockets. Dominated by a large black pupil, owls are able to receive an enormous amount of light on to their retina, making a nocturnal lifestyle that bit easier.

But what the owls lack in ocular flexibility they more than makes up in ability to maximise their field of view.

With extra vertebrae for a more flexible neck and adaptations to prevent blockage of the network of blood vessels, owls are able to famously rotate their heads almost all the way round.