Pygmy Marmoset

The Pygmy Marmoset (Callitrichidae Cebuella) is native to rainforests of the western Amazon Basin in South America. it is notable for being the smallest monkey and one of the smallest primates in the world, at just over 100 grams.  It is generally found in evergreen and river edge forests and is a gum-feeding specialist or a gummivore.
These monkeys may also make visual displays when threatened or to show dominance. Chemical signaling using secretions from glands on the chest and genital area allows the female to indicate to the male when she is able to reproduce. The female gives birth to twins twice a year and the parental care is shared between the group.