From Michael Roger
More than 20 years ago I read somewhere that a squid's visual acuity is eight times that of humans. Ever since then I've wondered why.
Now I read that an inky cloud helps squid hunt (5 March, p 17). Have ink and sharp-sightedness evolved hand-in-hand to provide optimum turbidity to hide and the keenest eyesight to see through it?
Vale, Guernsey, UK
