Jeremiah, Ontario asked:
Is it true that the colour red makes bulls angry? Is there anything biological about it, or is it a myth?
Bulls eyes are dichromatic - they have two colour-detecting pigments in their retinae. That means they can see red, but they can also see many other colours too. But, because they are dichromats they would see colours in a similar way to a colour blind person. In other words, there's nothing special about red; it's more likely to be that the bull is excited by someone wearing silly, bright clothes, dancing about and flapping something in the bull's direction. The bull is generally hot, bothered and fed up, making it more likely to attack. But there's no evidence that there's anything special about the colour red for a bull...