Roosmalens’ Dwarf Marmoset

Roosmalens Dwarf Marmoset

The Roosmalens’ Dwarf Marmoset (Callibella Humilis), also known as the Black-Crowned Dwarf Marmoset, is a New World Monkey in the Callitrichidae family of monkeys and can be found in certain areas of the Amazon rainforest in Brazil. The Roosmalens’ Dwarf Marmoset has the smallest distribution area of any primate in South America, making it very rare to spot. In fact, it is one of the newest additions to the New World Monkey family, officially being added in the year 1998. This is predominately because of their very low population and small area of inhabitance.


The Roosmalens’ Dwarf Marmoset inhabits a small area ranging from the east bank of the lower Madeira River to the west bank of the Aripuanã River in Brazil. The small area of its range combined with its level of isolation makes the Roosmalens’ Dwarf Marmoset any incredibly rare monkey to see. Spending most of its time in the canopy of the rainforest, the Roosmalens’ Dwarf Marmoset is considered diurnal and arboreal; and is very rare to spot foraging at ground-level.


Similar to most of the Marmoset family, the Roosmalens’ Dwarf Marmoset feeds almost exclusively on plant exudates such as sap, gum, and latex found by gouging the trunks of the native trees. It has claws as opposed to nails, which makes if very similar to other marmosets who feed off tree sap. It also has teeth similar to other marmosets, specially designed to access the plant exudates they prefer to eat. They will also eat small insect when food is in short supply or they just want a little variety.

Fun Roosmalens’ Dwarf Marmoset Facts

  1. This breed of monkeys is the second smallest in the world, proceeded only by the Pygmy Marmoset.
  2. Unlike most Marmosets, the Roosmalens’ Dwarf Marmoset only gives birth to one offpring at a time. Most Marmosets give birth to twins.
  3. It was first discovered in 1996 by Marc van Roosmalen when a river trader gave him a milk can with the tiny monkey inside. Suspecting it to be a new breed, he spent 2 years searching for its habitat before officially declaring it a unique species.
  4. The Roosmalens’ Dwarf Marmoset has the smallest distribution of any primate in Amazonia.