About 83% of the pygmy marmoset population lives in stable troops of two to nine individuals, including a dominant male, a breeding female, and up to four successive litters of offspring.

Chemical signaling using secretions from glands on the chest and genital area allow the female to indicate to the male when she is able to reproduce.

[8] The evolution of this genus diverged in terms of body mass from typical primates, with a high rate of body-mass reduction.

This involves large decreases in prenatal and postnatal growth rates, furthering the thought that progenesis played a role in the evolution of this animal.

[10][11] The fur colour is a mixture of brownish-gold, grey, and black on its back and head and yellow, orange, and tawny on its underparts.

[11] It has many adaptations for arboreal living, including the ability to rotate its head 180° and sharp, claw-like nails used to cling to branches and trunks of trees.

[12][13] Its dental morphology is adapted to feeding on gum, with specialised incisors that are used to gouge trees and stimulate sap flow.

The cecum is larger than usual to allow for the greater time gum needs to break down in the stomach.

[12][14] Pygmy marmosets can be found in much of the western Amazon Basin, in Brazil, Colombia, Ecuador, Peru, and Bolivia.

The western pygmy marmoset, C. pygmaea, occurs in the state of Amazonas, Brazil, eastern Peru, southern Colombia, and north-eastern Ecuador.

They gnaw holes in the bark of appropriate trees and vines with their specialized dentition to elicit the production of gum.

[15] A group's home range is 0.1 to 0.4 ha (0.25 to 0.99 acres), and feeding is usually concentrated on one or two trees at a time.

[7] Pygmy marmosets have adapted insect-like claws, known as tegulae, to engage in a high degree of claw-clinging behaviors associated with plant exudate exploitation.

The pygmy marmoset uses special types of communication to give alerts and warning to its family members.

[21] Infant pygmy marmosets, along with their parents, twins, and other siblings, form co-operative care groups.

Vocalizing gives the infant advantages, such as increased care, and allows the entire family to coordinate their activities without seeing each other.

Males have less time to search out food sources and forage due to the constraints of their infant-caring responsibilities and predator vigilance.

Varying responses to individual callers were only observed when the call was given spontaneously from another animal rather than being played back from a recording, with one exception.

Since pygmy marmosets are often found in the rain forest, plant life and the humid atmosphere add to the normal absorption and scattering of sound.

Scent glands on her chest, anus, and genitals are also rubbed on surfaces, which leave chemical signals about the reproductive state of the female.

[28] Pygmy marmosets also perform visual displays such as strutting, back-arching, and piloerection when they feel threatened or to show dominance.

Particularly in areas of heavy tourism, pygmy marmosets have a tendency to be less noisy, less aggressive, and less playful with other individuals.

Due to its small size and relatively docile nature, captured pygmy marmosets are often found in exotic pet trades.

[35] Generally, a pygmy marmoset's lifespan is 15 to 20 years; they are known to have a shorter life in the wild mainly because they fall out of trees.

[35] Understanding their natural diet is also important because it helps maintain their good health from the necessary protein, calcium, and other nutrients they need to survive.

Understanding the laws within those countries is important when considering owning or taking care of a pygmy marmoset.