 While this marking resembles a face, it is actually located at the posterior of the Saddleback caterpillar.This is an example of defensive mimicry which can be seen in other moth species such as "Deilephila elpenor" (elephant hawk-moth) which exhibits snake like features in order to deter predators.It is not uncommon for these facial features to be represented on the posterior as it is believed to be used to misdirect predators and is often called automimicry or intraspecific mimicry.