Pygmy marmoset  (Cebuella pygmaea)

The pygmy marmoset is classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix I of CITES (3).

Subspecies: Eastern pygmy marmoset (C. p. niveiventris) is also classified as Least Concern (LC) on the IUCN Red List (1).

The diminutive pygmy marmoset is the smallest monkey in the world (4). Its tiny body has greyish, black mixed with buff, or brownish-gold fur on the back, sometimes with a greenish tinge, and white, tawny or orangish fur on the underparts (2). The squirrel-like hands and feet are yellowish or orangish (2) (5), and bear sharp claw-like nails which are suited to clinging to trees (4). The tail has indistinct dark rings on a lighter background (2) (5). A longer mane of hair surrounds the face, covering the ears (5), and white marks at the edges of the mouth and a white vertical line on the nose are thought to make communication through facial expressions more conspicuous in the dim light of dense forest (4). Female pygmy marmosets are slightly heavier than males (5). It is a fairly quiet monkey, but can produce a variety of vocalisations for communicating, including a high, sharp warning whistle and a clicking sound to indicate threat (2).

The pygmy marmoset inhabits the Amazon basin (5). Two subspecies are recognised: Cebuella pygmaea pygmaea is found in the state of Amazonas, Brazil, (north of the Rio Solimões), eastern Peru (north of the Río Maranõn), southern Colombia, northern Bolivia and north-eastern Ecuador. Cebuella pygmaea niveiventris also occurs in the state of Amazonas, Brazil, eastern Peru, and as far south as northern Bolivia, but is found south of the Rio Solimões and Río Maranõn (1).

This tiny primate inhabits lowland, tropical evergreen forests, most often on river floodplains (5), showing a preference for areas which are flooded for more than three months of the year (4). It seems able to tolerate disturbed habitats (4).

This tree-dwelling primate is solely active during the daylight hours, particularly in the cooler mornings and late afternoons (2). It lives in stable troops of 2 to 15 individuals, usually consisting of an adult pair and their offspring (2). They rest huddled together at night, often in a dense tangle of vines (4), around seven to ten metres above the ground (2).

Moving around its forest habitat by running along branches, up and down trunks, and leaping between trees, the pygmy marmoset feeds on fruits, buds, insects, and exudates from trees (2). Its lower canine teeth are specially suited to gouging holes in trees to enable it to feed on exudates, and within the range of each marmoset group one or more trees can be found which are riddled with holes (2).

The majority of pygmy marmoset births occur in two peaks each year: between November and January, and May and June (2). In captivity, gestation lasts around 20 weeks and most of the births are of twins (2) (5). Sexual maturity is reached between 18 and 24 months and one pygmy marmoset is known to have lived for over 11 years (2).

The pygmy marmoset faces no significant threats and is therefore classified as Least Concern on the IUCN Red List (1). Despite significant habitat destruction occurring in some parts of its range, this does not seem to have affected pygmy marmoset numbers (4). However, some populations, such as in the Putumayo region of Colombia, may be impacted by collection for the pet trade (2), and those inhabiting areas visited heavily by tourists exhibited slightly different behaviour, which has raised some concern that this may affect their reproductive capabilities (4).

The pygmy marmoset is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully monitored (3). To reduce habitat degradation and human disturbances, there have been some efforts to raise awareness in local communities. For example, a programme in Ecuador was initiated to educate children in the importance of conserving primates (4). Such efforts are vital if the pygmy marmoset it to remain globally unthreatened.

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the pygmy marmoset see:

• Cawthon Lang, K.A. (2005) Primate Factsheets: Pygmy marmoset (Callithrix pygmaea). Primate Info Net, University of Wisconsin, Madison. Available at:
  http://pin.primate.wisc.edu/factsheets/entry/pygmy_marmoset