The Buffy-headed marmoset is a rare species of marmoset native to forests of Brazil. These marmosets have black and grey fur on their body, blackish and pale fur on their tails and yellowish underparts. They have orange to yellow fur on their crown and cheeks. Like all marmosets, they have claws instead of nails on all digits except the big toes. This adaptation allows marmosets to cling to trees with ease while feeding on their favorite food, tree gum.
Buffy-headed marmosets are found in south-eastern Brazil. They occur in southern Espírito Santo and possibly northern Rio de Janeiro and their distribution extends also into Minas Gerais. These marmosets live in tropical moist forests.
Buffy-headed marmosets are social arboreal animals. They live in groups of up to fifteen consisting of related individuals, where females dominate males. Each group usually contains only one breeding female. Buffy-headed marmosets are active during the day. Due to their small size, these marmosets have many predators and have developed four distinct patterns of predator avoidance. Primarily, they avoid aerial predators through low-intensity alarm signals, emitting soft, closed-mouth whistles to warn other group members. Another behavior in dealing with aerial threats is a high-intensity alarm. They will produce a half-mouthed, open whistle to alert other members to take cover under branches or trees, sometimes immediately ceasing movement to avoid exposure. The third type of anti-predator alarm is for low-intensity terrestrial threats. A few marmosets in the group will give a call to the rest, alerting them of a possible threat such as a snake. Marmosets then “mob” the predator by amassing in large groups, thus not giving the predator a chace to attack. The last reaction is for high-intensity terrestrial situations. In instances of dealing with larger or more threatening predators, such as the tayra, marmosets amass in a large group, yelping in piercingly loud manner to try and scare the predator away.
Buffy-headed marmosets are herbivores. They primarily eat fruits, gum, and plant exudates. They may also consume bird eggs and nestlings. Additionally, they may prey on both vertebrates and invertebrates: primarily orthopterans, phasmids, coleopterans, caterpillars, and tree frogs.
Buffy-headed marmosets are monogamous and mate for life. However, polygyny (males mate with more than one female) and polyandry (females mate with more than one male) also exist. Breeding season occurs year-round. Females usually give birth to twins after the gestation period that lasts 140-150 days. Newly born infants are nursed by their mothers for about one month after birth. The rest members of the group also help to care of young. Males in this species become reproductively mature at around 9-13 months of age, while females attain maturity at 20-24 months.
Buffy-headed marmosets are threatened by the fragmentaion of their habitat through mining, agriculture and cattle ranching, tree plantations, and urbanization. These marmosets also suffern from hunting for pets.
According to the IUCN Red List, the total population size of Buffy-headed marmosets is fewer than 2,500 mature individuals. This species’ numbers are decreasing and it is currently classified as Endangered (EN) on the IUCN Red List.
Buffy-headed marmosets are likely to play an important role as seed dispersers in their ecosystem. These marmosets may also influence plant growth as they feed on plant gums.