Fact: Invisibility cloaks really exist.
As my mother always told me, amazing things come in small packages. And so it is with the little bobtail squid, which has the power to become invisible.
Bobtail squids have a dedicated ‘light organ’, which is inhabited by a specific species of bacteria (Aliivibrio fischeri, if you must know). These bacteria live in a symbiotic relationship with the squid, meaning that both species benefit from their interaction: the bacteria are provided with food and in return – through some biochemistry that seems an awful lot like magic – produce light.
When viewed from below, prey are silhouetted against the light filtering down from the ocean’s surface, and so are easy pickings for hungry predators. The cunning bobtail squid directs this bacteria-produced light downwards into the ocean depths, making it effectively invisible to predators lurking in the deep.
The elegance of this camouflage is astounding: at night, the squid even modifies the wavelength of light emitted from its light organ to make it closer to that of moonlight, helping it to match the colour and brightness of the light above it and thus stay hidden.
The bobtail squid isn’t alone either – this strategy (called counter-illumination) is actually one of the most popular ways for aquatic animals to keep themselves alive. Mother nature has put James Bond and his invisible Aston Martin to shame.
‘Another one of Mr Shaunak’s Little Bites of Science’
Image under Creative Commons license, taken my Mark Norman