Why does the colour of head lice change?
A head louses outer layer or ex-skeleton is made up of a very thin, bone-like material that when viewed in light, is the colour of light brown. As lice feed on blood, however, the appearance of this outer layer darkens. As the blood begins to digest, the colour begins to lighten up again. Thats why their colouring changes so often. The color is really a matter of how much blood is not yet digested.
