The brown-mantled tamarin specifically enjoys tree sap in the late dry season and early wet season. In order to access the plant exudates, they utilize pre-existing holes made by other primates, primarily the Pygmy marmoset rather then creating a hole themselves. Behavior Social behavior Brown-mantled tamarin social groups average 8 individuals and sleep in low lying palms of the Oenocarpus bataua tree and tree hollows, relying on concealment as a strategy of predator protection. Their territory may occasionally overlap with other species of callitrichids including the Pygmy marmoset, Goeldi's marmoset and Moustached tamarin. It is common for this species to defend their territory however not all intergroup encounters are aggressive. Vocalization Similar to other species of callitrichids, the brown-mantled tamarin utilizes vocalization to communicate amongst each other, they have many different forms of vocalizations including a soft trill contact call, a long distance loud whistle and an alarm call which all convey a different message, these calls can sound like chirps or whistles. They do not however use their vocalization skill as their main form of communication, the brown-mantled tamarin will sound alarm calls when in proximity of potential danger from intruders or predators, individuals will respond to the alarm calls which aids in determining the location of each group member. Due to the geographic distribution of the brown-mantled tamarin, their territory often overlaps with that of other primate species and it is not uncommon for different species such as the Moustached tamarin to respond to their calls, even though every species has a different sounding alarm calls. Olfactory communication This species possess a well developed olfactory communication system with specialized glands in the anogenital, suprapubic, and sternal regions, they can perceive information about species, subspecies, sex, and individual identity in the sender's scent marks as well as females relaying the status of their reproductive condition through their scents. Olfactory communication is substantially different from other forms of communication, scent marks are deposited in the substrate and can be detected long after they were deposited. There are three functional motives for scent marking behavior amongst New World primates which include territorial function, regulation of social and reproductive dominance and mate attraction. The use of scent marking for territorial defense was hypothesized to be one of the main functions within brown-mantled tamarins, as they typically would mark more on the periphery of their area of territory, however spatial patterns of scent