It occurs in southern Espírito Santo and possibly northern Rio de Janeiro and its distribution extends into Minas Gerais.

These marmosets have a low metabolic rate, as well as an enlarged cecum that allows consumption of food that is high in fiber.

Primarily, buffy-headed marmosets avoid aerial predators through low-intensity alarm signals, emitting soft, closed-mouth whistles to warn other group members.

These marmosets will send out a half-mouthed, open whistle to alert other members to take cover under branches or trees, sometimes immediately ceasing movement for the purpose of avoiding exposure.

Additionally, they may prey on both vertebrates and invertebrates: primarily orthopterans, phasmids, coleopterans, caterpillars, and tree frogs.

Because this group of marmosets primarily inhabits areas in which fungi are abundant, it tends to be a consistent source of sustenance throughout the year.