We see them, but do animals see united colours of Benham’s disc too?
I heard of a man who worked as a magician after World War II and in his performances used a disc with a strange pattern of black and white lines. However, when turned around and spun at high speed, the disc’s black and white pattern created the impression of faint reddish or orange, even greenish or yellowish colours in human observers. —>—>
Fish without eyes
It is sometimes quite shocking what some people think the work of an animal biologist consists of. One day, when visitors to our house took a look at my aquarium and admired the fish in it, my ears had to hear the following comment: “Very interesting, but doesn’t it hurt them when you remove their eyes?” “What do you think?”, came my reply, “they are blind fish. They never have any eyes! They are Mexican cave fish, Astyanax mexicanus.” Stupid visitors (I did not say that), but they obviously did not know that some species of fish are naturally eyeless.
“Fly eyes are the better to see you with”
When Little Red Riding Hood in the Brother Grimm’s fairy tale of the same name asked the big bad wolf: “But Grandmother, what big eyes you have,” the wolf replied: “The better to see you with, my dear”. But there was no suggestion that the wolf had horny eyes. And wolves in Malaysia (if there ever had been any) also would not have them. However amongst the many truly weird looking insects that occur in Malaysia there are the “Stalk-eyed Flies” and these flies, as their name suggests, do possess eyes at the end of surprisingly long stalks which project laterally from their heads like the horns of a Watusi cow. —>