This squid has two eyes... that don't look the same

In the squid Histioteuthis heteropsis, both eyes are not the same size. The left is large, while the right is significantly smaller. This asymmetry seems strange until one considers the lighting of its middle: above, a weak light descends from the surface; below, the water becomes darker.

The large eye, facing upwards, helps to spot silhouettes in this diffused light. The little one searches down the bioluminescent fragments of prey or predators. The researchers therefore describe two visual equipment adapted to two types of signals, instead of an identical pair.

Its red color also contributes to its camouflage, because the red light does not penetrate to these depths: it appears dark. The glaring look revealed by the projectors of a robot is therefore not the one that another animal necessarily sees. To understand his mismatched eyes, we must first mentally turn off our own lighting.