Finger monkeys are actually pygmy marmosets from the rain forest. These primates belong to the family Callitrichidae, species Cebuella and genus C. pygma. They are the tiniest living primates in the world. They are also known by the names "pocket monkeys" and "tiny lions". Theses adorable guys hug and grip on to your finger so tight that it pulls at your heartstrings and you want to take them home with you.