All of the following animals are mammals, except one. Which one isn't a mammal?
Considering the nine-banded armadillo, black-bellied pangolin, hairy woodpecker and bottlenose dolphin, the answer is: Hairy woodpecker.
Despite its name, the hairy woodpecker doesn't have hair, and it's a bird, not a mammal. Covered in stripes of black and white feathers, these medium-sized woodpeckers live in forests throughout North America, and have long tail feathers to lean against on tree trunks.
Slightly larger than a songbird but far more conspicuous, woodpeckers come in many different shapes and sizes in North America alone. These curious creatures are most often small, red, black and white birds with accented heads and long beaks. Their tail feathers are specially designed to support the bird as it holds itself on a tree trunk, and have two back toes to lean back on if they get wobbly.
Though hitting your nose again and again into bark would be painful for us humans, woodpeckers don't have much of a problem. Woodpecker beaks have evolved to help distribute the shock of the hit without taking any damage. What's more: woodpeckers actually enjoy making noise with their beaks! In the animal world, woodpeckers are the only creatures to routinely make a sound with something other than a part of its body. They will drum on a variety of objects to communicate territory, to attract mates, locate food, or maybe even play.
All types of woodpeckers are perfectionists in their tree-holing craft. Many species of woodpecker nest in tree cavities with access holes they carve out themselves, and every hole is a perfect circle (Pileated woodpeckers, on the other hand, make a nest hole that is an oval or oblong). See the perfection for yourself: