Pygmy marmosets are the smallest living species of monkey in the world today. Not only are they small, their brown/grey colouring makes them very well camouflaged with the trees and surroundings in their environment, making them very hard to spot. Pygmy marmosets have incredibly flexible necks and can rotate their heads nearly 180 degrees and are capable of using their teeth to create near perfect circles within trees - great for extracting tree sap and gum. They are the smallest monkey in the world (but not smallest primate).