The tiny "Happy-face" spider can be found in the rain-forests of only four islands in the world-Oahu. Molokai, Maui and Hawaii. Measuring around 1/5 in(5mm), no one really knows why the colorful patters on the spiders' backs look like happy faces.
One theory is that the patterns evolved to confuses is nevertheless under threat from a growing number of animals that have been introduced to the islands. Perhaps they need to evolve a scary face!