Pygmy marmosets spend their time in the trees, and are most active during the day. They live in groups of two to six, which includes the adult pair and its offspring. Males and females usually mate for life. Individuals communicate using scent markings and a variety of high-pitched calls, facial expressions, and postures. When threatened—as by an eagle, a snake, or a cat—a pygmy marmoset group will make a chorus of chirps as warning to others. As with most primates, grooming is also an important part of social bonding for marmosets.
Arboreal (tree-living) pygmy marmosets feed primarily on tree sap or “gum,” which they procure by gouging holes in trees to create a steady, sticky flow. This process can be very time-consuming—the monkeys spend much of their day gnawing tree trunks or large branches from which they can collect the gum. They also eat fruit, nectar, and small animals such as insects and spiders.
Pygmy marmoset mothers have a gestation period of 119–142 days. They usually give birth to twins, and occasionally to triplets or a single offspring. Both parents work together to rear their babies with the help of any older offspring. Pygmy marmoset dads carry their babies on piggyback for the first few months, handing them over to mom when it’s time to nurse. Pygmy marmosets can live into their early twenties.
Each year, tens of thousands of acres of tropical forests are destroyed to make room for agriculture and human settlements. Though more monkey species—a total of 85—live in the New World than anywhere else, they are disappearing as their habitat dwindles. In fact, one in four are endangered or close to extinction. In addition to habitat degradation, pygmy marmosets are also trapped and sold for the pet trade. Though the species is under pressure, it is not currently endangered. This is partially due to their adaptability to environmental changes caused by humans.