Callithrix humilisRoosmalens' dwarf marmoset

Geographic Range

Roosmalen's dwarf marmosets are endemic to the central part of the Amazonian Rain forest in Brazil. They occur in a very small area "from the west bank of the lower Rio Aripuanã, from the mouth with the Rio Madeira just SW of the town of Novo Aripuanã south at least to the village of Tucunaré on the west bank of the Rio Aripuanã, and along the east bank of the Rio Madeira south as far as the mouth of the Rio Mataurá. The southern limit for the species, in the interfluve delineated by the Rios Madeira, Mataurá and Aripuanã, is probably the headwaters of the Rios Mariepauá and Arauá" (Roosmalen and Roosmalen, 2003 p 4). (Roosmalen and Roosmalen, 2003)


Roosmalen's dwarf marmosets are found in disturbed primary and secondary terra firme rain forests and terra prestas forests. Roosmalen and Roosmalen explain that terra prestas are soils made by pre-Columbian farmers who mixed "decomposed organic material...and large quantities of charcoal, calcium and phosphates" near bluffs and lakes. At first, it was assumed that they only occur away from human habitations, but it seems they prefer disturbed forest areas near human inhabited areas such as plantations, gardens, and fields. (Roosmalen and Roosmalen, 2003)

Physical Description

Roosmalen's dwarf marmosets are very small monkeys. They have golden to grayish yellow fur on the body with a darker almost black layer underneath. The ears and face are naked and flesh-colored, there is a triangular crown of fur on the head and white eyebrows which extend all the way to the temples, and they have a long black tail. Their coloration changes with age. They weigh from 150 to 185 grams, with females being slightly larger. (Roosmalen and Roosmalen, 2003)

  • Sexual Dimorphism
  • female larger
  • Range mass
    150 to 185 g
    5.29 to 6.52 oz
  • Range length
    38 to 39 cm
    14.96 to 15.35 in


Not much is known about reproduction in Roosmalen's dwarf marmosets, but it is thought that they are very flexible, forming monogamous, polyandrous, and polygynandrous groups. Observations show that there is more than one reproductive female in a group and imply that there are obligate singleton births. Biological mothers carry young and aid is not provided by the father or any other members of the group. (Aguiar and Lacher, Jr., 2003)

Roosmalen's dwarf marmosets give birth to a single offspring at a time. This is different from most marmoset species, which give birth to twins. Other aspects of reproduction in Roosmalen's dwarf marmosets are not well known. (Roosmalen, et al., 1998)

  • Average number of offspring

Not much is known about the reproduction in Roosmalen's dwarf marmosets. Young are born atricial and cared for and nursed by their mother.

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents


The oldest animal of this species in captivity was 36 months old and she died shortly after giving birth. Wild longevity is not reported in the literature. (Roosmalen, et al., 1998)

  • Range lifespan
    Status: captivity
    36 (high) months


Roosmalen's dwarf marmosets occur in family groups with individuals usually numbering 6 to 8. However, groups up to 30 have been observed. No antagonistic behavior has been witnessed, nor scent marking to display the home range. (" Callibella humilis (Black-crowned Dwarf Marmoset, Roosmalen's Dwarf Marmoset)", 2012; Roosmalen and Roosmalen, 2003)

Home Range

Home range size in Roosmalen's dwarf marmosets is not reported in the literature.

Communication and Perception

Not much is known about the communication of this species, though we do know that they are social animals, living in groups of 6 to 30. Scent marking has not been observed in this species, even though it is very common in many other primate species. It is likely that vocal cues and visual communication play an important role, as they do for most primates. (Roosmalen and Roosmalen, 2003)

Food Habits

In winter months, when fruit is scarce, Roosmalen's dwarf marmosets feed on tree gum. They cling vertically to trees with strong claw-like nails, which also allow them to cut holes in the bark and feed on saps and gums. ("IUCN Red List", 2012; Roosmalen and Roosmalen, 2003)

  • Plant Foods
  • fruit
  • sap or other plant fluids


The only reported predators of Roosmalen's dwarf marmosets are domestic cats, domestic dogs, and birds of prey. It is likely that they are also preyed on by arboreal snakes and wild, arboreal felids. No predator defense had been witnessed but, as social species, they may share vigilance activities and warn each other of predator approach. (Roosmalen and Roosmalen, 2003)

Ecosystem Roles

Roosmalen's dwarf marmosets provide a service, though probably unknowingly, to both tamarins and Parkia fruits. The tamarins who cannot gouge hole themselves, are able to feed on exudate from the holes made my Callibella individuals. (Roosmalen and Roosmalen, 2003)

Economic Importance for Humans: Positive

There are no known benefits to humans of Roosmalen's dwarf marmosets. However, their range is believed to have one of the highest levels of primate diversity on Earth. (Roosmalen, et al., 1998)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

It could be argued that Roosmalen's dwarf marmosets have a small negative impact on the humans in their local environment because they feed on fleshy fruits grown in gardens. However, they typically take little fruit and, as noted by Roosmalen et al. (1998), the locals do not seem to mind the small marmosets. (Roosmalen, et al., 1998)

  • Negative Impacts
  • crop pest

Conservation Status

Roosmalen's dwarf marmosets are considered vulnerable by the IUCN due to their very small range and the potential for human habitat destruction in that range. No part of their range is legally protected and it is vulnerable to expanded agricultural use. ("IUCN Red List", 2012)

Other Comments

Roosmalen's dwarf marmosets, Callibella humilis, were previously included in the genus Callithrix and are also known as black-crowned dwarf marmosets. (" Callibella humilis (Black-crowned Dwarf Marmoset, Roosmalen's Dwarf Marmoset)", 2012; Roosmalen and Roosmalen, 2003)


Melissa McCullough (author), Georgia Southern University, Michelle Cawthorn (editor), Georgia Southern University, Tanya Dewey (editor), University of Michigan-Ann Arbor.



living in the southern part of the New World. In other words, Central and South America.

World Map


uses sound to communicate


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.


Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

  1. active during the day, 2. lasting for one day.

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


an animal that mainly eats fruit


An animal that eats mainly plants or parts of plants.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


Having one mate at a time.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).


having more than one female as a mate at one time


rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


uses touch to communicate


Living on the ground.


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.


2012. "

Callibella humilis (Black-crowned Dwarf Marmoset, Roosmalen's Dwarf Marmoset)
" (On-line). IUCN Red list of threatened species. Accessed February 02, 2013 at

International Union for Conservation of Nature and Natural Resources. 2012. "IUCN Red List" (On-line). International Union for Conservation of Nature. Accessed February 20, 2012 at

Aguiar, J., T. Lacher, Jr.. 2003. On the Morphological Distinctiveness of Callithrix Humilis van Roosmalen et al., 1998. Neotropical Primates, 11 (1): 11-18.

Roosmalen, M., T. Roosmalen. 2003. The Description of a New Marmoset Genus, Callibella (Callitrichinae, Primates), Including its Molecular Phylogenetic Status. Neotropical Primates, 11(1): 1-12. Accessed April 24, 2013 at

Roosmalen, M., T. Roosmalen, R. Mittermeier, G. de Fonseca. 1998. A New and Distinctive Species of Marmoset (Callitrichidae, Primates) from the Lower Rio Aripuana, State of Amazonas Central Brazilian Amazonia. Goeldiana, 22: 1-27. Accessed February 04, 2013 at