Common Marmoset

Common marmosets are native only to east-central Brazil. They have been introduced into other areas and live within the cities of Rio de Janeiro and Buenos Aires, Argentina. Marmosets can be found in a number of forest habitats. They live in Atlantic coastal forests as well as semideciduous forests farther inland. They can also inhabit savanna forests and riverine forests. Marmosets are successful in dry secondary forests and edge habitats.

Diet. The common marmoset's claw-like nails, incisor shape, and gut specialization reflect their unique diet, which is primarily made of plant exudates and insects. Common marmosets feed on gum, sap, latex, and resin. They use their nails to cling to the side of a tree, and with their long lower incisors, chew a hole in the tree. The marmoset then licks up the exudates or swoops them with the teeth. From 20 to 70% of the marmoset's feeding behavior includes eating exudates. Exudates provide marmosets with a reliable food source in their seasonal habitat. They rely on these foods particularly between January and April, when fruit is not abundant. A marmoset may visit a tree hole multiple times, including those made by other animals. In addition to exudates, insects also prove an important food source for marmosets, making up 24-30% of their food. The small size of marmosets allows them to stalk and ambush them. …

Common marmosets have a complex mating system. They were thought to be monogamous, but both polygamy and polyandry have been observed. Nevertheless, most matings are monogamous. Even in groups with two breeding females, the subordinate female often mates with males from other groups. Subordinate females usually do not give birth to fit offspring. Mating with extra-group males may allow the female to find potential mates in the future. Females that mate successfully but lose their young move to other groups and may gain dominant breeding positions.

The breeding individuals in a group need the other members to help raise their young. Thus, the pair behaviorally and physiologically suppresses the reproduction of the other members of the group. Since these suppressed individuals are likely related to the breeding pair, they have an incentive to care for the young, as they share genes with them. In addition, the presence of a related male affects female ovulation. Female ovulation does not occur when their fathers are around, but does occur when an unrelated male is nearby, instead. They also display aggressive behavior towards their mothers, possibly to displace them. When conditions are right for them to breed, adult females breed regularly for the rest of their lives. Females flick their tongues at males to solicit mating. …