Why do toucans have such a large, colorful bill? [VID: Why do toucans have such a large, colorful bill? Their bill can be four times the size of their head and nearly as long as their body. Some experts believe the colorful bill evolved to attract potential mates. Others believe that it’s useful in scaring away predators or other competitors for food. The toucan can also use its bill to get at hard-to-reach food. Toucans are known for reaching deep into tree cavities to grab eggs from other bird