This pygmy mouse lemur inaugurates The Daily Mammal’s first-ever theme week! To celebrate my recent revelation that I’m actually not nocturnal, but rather a morning person who has difficulty waking up, I am pleased to introduce Nocturnal Week! The nocturnal pygmy mouse lemur is the world’s smallest primate. Andy requested this fellow. You will often see photographs of the little lemur in a person’s hand, which shows how tiny he is. They really are the size of a mouse.