Moustached Tamarin, Saguinus mystax
MOUSTACHED TAMARIN
Saguinus mystax
Geographic Distribution and Habitat
The moustached tamarin (Saguinus mystax), also known as the Spix’s moustached tamarin, is a primate species native to South America’s Brazil and Peru, specifically between the western regions of Brazil and eastern areas of Peru. Notably, the geographic range of the moustached tamarin is defined by the size of the Amazon rainforest, the largest tropical rainforest on Earth. Across Peru and Brazil, many rivers act as natural geographic barriers for moustached tamarins, including the Javari River, the Purus River, and the Amazon River.
On average, the home range of a moustached tamarin is between 0.09 to 0.54 square miles (0.23 to 1.4 square kilometers), which is roughly smaller, if not the same size, as Disneyland!
As the world’s largest tropical rainforest, the Amazon rainforest is characterized by its unique climate, diverse ecosystem, and size. Excluding Brazil and Peru, the Amazon rainforest spans an additional six countries, and has an estimated total size of 2.59 million square miles (6.7 million square kilometers). Generally, the Amazon is consistently warm and has a humid climate. The average annual temperature throughout the Amazon hovers around 80 degrees Fahrenheit (27 degrees Celsius), and over the course of a year, it receives an average rainfall of between 6 to 10 feet (1.8 to 3 meters)!
Within the rainforest, moustached tamarins inhabit all levels of the forest, including the canopy, understory, underbrush, and forest floor. Although they can be seen throughout all levels, moustached tamarins mainly travel and forage in the forest’s middle levels (understory and underbrush).
Named after the German primatologist Johann Baptist von Spix, the Spix’s moustached tamarin was first described by primatologists in 1823. Johann Baptist von Spix, known for his grand expedition to Brazil in the 1800s, brought a variety of creatures and specimens, including plants, insects, mammals, birds, amphibians, and fish, back to Germany for scientific study. Upon his return, he meticulously analyzed his zoological collection and published several descriptions of species to European science. These particular findings proved to be a significant basis for the establishment of today’s National Zoological Collection in Munich, Germany.
Currently, there are no recognized subspecies associated with the moustached tamarin (Saguinus mystax), and according to the IUCN’s Red List of Threatened Species, the taxonomic status of the species remains to be determined in future genetic analysis.
Size, Weight, and Lifespan
The moustached tamarin is a sexually dimorphic monkey, meaning males and females have slight variations in their appearance. For example, females are larger in size and heavier than their male counterparts. On average, the head-to-body length for adult males and adult females is between 9.53 to 9.69 inches (24.2 to 24.6 centimeters), and the average weight is between 1.04 to 1.38 pounds (472 to 626 grams). Regardless of sex, the tail of a moustached tamarin adds 14.57 inches (37 centimeters) to the monkey’s body length.
The exact lifespan of a wild moustached tamarin is unknown, but the estimated length is anywhere between 10 to 20 years.
Appearance
Naturally, moustached tamarins have hairy brown or black faces, chocolate-brown eyes, and small, pink noses. Although their other features are just as noteworthy, they are ultimately named for their white “moustaches”, which are the direct result of an evolutionary alteration.
Moustached tamarins have white “moustaches” due to the reduction of melanin production in the hair follicles that surround their mouths. Hair color is determined by melanin, a naturally occurring pigment that gives color to skin, hair, and eyes. Melanin production begins in large cells called melanocytes, which can be found all over an individual’s body. This melanin reduction leads to the gradual whitening of hair. Although factors such as stress, aging, or environmental factors can influence the timing of this process, moustached tamarins are genetically predisposed to this characteristic and can be identified in an individual as early as infancy. There is no singular reason to explain this phenomenon, but scientists have determined that some primates lack melanin around their mouths due to factors related to their social behavior, visual communication, and ability to camouflage.
Tamarins, like most primates, have five fingers on each hand and five toes on each foot. Unlike some other primate species, moustached tamarins have claw-like nails on each of their digits, besides the thumbs and big toes. Claw-like nails are advantageous for tamarins because they provide them with a stronger grip for climbing and leaping, as they can dig into trees and branches more easily. Like humans, tamarins have flat nails on their thumbs and big toes, which help enhance their grasping abilities for food and small objects, providing tamarins with better dexterity and fine motor movement, or precise actions involving the small muscles of the hands. Tamarins do not have prehensile tails, so they are unable to grab and manipulate items with an additional appendage. Instead, the tails of tamarins are utilized for balance and support, which proves especially important when traversing the forest.
Diet
Moustached tamarins are omnivorous, frugivorous, and insectivorous primates, which means that they regularly consume large quantities of plant, animal, and insect products on a daily basis.
By definition, an omnivore is an animal that regularly consumes large quantities of both plant and animal matter. Frugivorous primates thrive on eating mostly raw fruits and fruit-like produce, and insectivorous primates eat insects. As a preview of their dietary preferences, moustached tamarins often consume various food products within their home range, including fruits, fruit pulp, exudates, nectar, small invertebrates (animals without spines), or small vertebrates (animals with spines and skulls). Considering their geographic range, they could consume food products such as acai berries (Euterpe oleracea), passion fruits (Passiflora edulis), bananas (Musa acuminata Colla), Amazon milk frogs (Trachycephalus resinifictrix), and tarantula spiders (Theraphosidae).
Behavior and Lifestyle
As an arboreal primate species, Spix’s moustached tamarins spend the majority of their lives in the trees of the Amazon rainforest. In fact, tamarin species spend between 9 and 12 hours a day socializing, traversing, and foraging throughout their home range. Moustached tamarins move through quadrupedal locomotion, so they use all four of their limbs to get around. As noted previously, their claw-like fingers assist with their grip, making walking, running, and vertically climbing much easier. They are even known to climb up and down trees like squirrels! When they forage, they also use their long, extended fingers to extract and collect food products from various locations, such as vines, shrubs, tree hollows, etc.
Like other tamarin species, Spix’s moustached tamarins are also a diurnal primate, which means they are primarily active during the daytime and engage in rest and sleep after the sun goes down.
Moustached tamarins have many different predators, including birds or prey, snakes, and mammals. Examples include crested eagles (Morphnus guianensis), harpy eagles (Harpia harpyja), black-hawk eagles (Spizaetus tyrannus), jaguars (Panthera onca), cougars (Puma concolor), jaguarundis (Herpailurus yagouaroundi), anacondas (Eunectes akayima), and Amazon tree boas (Corallus hortulana).
When it comes to vision, on average, 60% of the female tamarin population possesses trichromatic vision. This unique ability allows individuals to distinguish the differences between greens, blues, and reds, helping them perceive a wide variety of colors in the natural world.
Since female tamarins are the primary caregivers of their young, enhanced vision is crucial for locating food quickly and efficiently. Compared to males, reproductively active females require food security because it impacts their reproductive success and ability to nurture their offspring. For instance, malnourished females often experience poor lactation outcomes when nursing, highlighting the importance of proper nutrition for healthy pregnancies and successful nursing.
The average troop size for a group of moustached tamarins can be anywhere between 3 to 12 individuals.
Because the Amazon is home to several different primates, many of these species have created interspecific associations with moustached tamarins over time. To have an interspecific association, two or more species must establish a relationship with each other, a shared habitat. As an example, across their geographic range, scientists and researchers have observed moustached tamarins forming relationships with other primates such as Geoffroy’s saddle-back tamarins (Leontocebus nigrifrons), Ávila Pires’ saddle-back tamarins (Leontocebus fuscicollis avilapiresi), and Spix’s saddle-back tamarins (Leontocebus fuscicollis fuscicollis). By establishing these associations, species might be more likely to detect predators or cause predator confusion; find food or access to specific food sources more easily; and establish tolerant relationships that result in reproductive advantages, without the risk of breeding competition.
Although these relationships generally prove successful, tamarins can be territorial. Considering how much overlap their home ranges have with one another, territoriality can be very dangerous, especially if multiple species intend to fight over food resources near important feeding sites.
Tamarins are highly communicative animals and often communicate through vocalizations, facial expressions, and scent markings.
Moustached tamarins have a diverse vocal range and communicate with one another through whistles, barks, chirps, growls, and squeaks. Unsurprisingly, troop members are able to recognize each other through their calls and can respond to long calls from other members when they are separated over long distances.
Facial expressions are particularly used to communicate emotions. For example, head-shaking, head-lowering, or frowning may communicate submission or unease, while tongue-flicking or grimacing may communicate anger, recognition, or curiosity. To their benefit, the appearance of a moustache makes many of these expressions even more apparent, as it draws attention to the animal’s face and mouth, evidently conveying the expression’s intent.
As a male behavior, moustached tamarins use scent marking as a form of olfactory communication, or the use of chemical signals, often through the sense of smell, that animals use to convey information and influence behavior. Males typically deposit their scent markings throughout their environment to project information about their reproductive status, health, identity, and dominance. These markings can also be used to establish territorial boundaries or mark the location of food resources for other troop members.
Moustached tamarins engage in two types of mating systems: polyandry or monogamy. In polyandrous relationships, females mate and reproduce with more than one male. Comparatively, in monogamous relationships, females and males have one mate for all their reproductive couplings.
The average gestation period, or the time between conception and birth, for a female moustached tamarin is between 140 to 145 days. After this period, mothers typically have two offspring that are fraternal twins. Biologically, fraternal twins arise from two separate eggs, or ovum, that have been fertilized by two separate sperm cells. Contrary to some belief, fraternal twins do not share the exact same genetic material as their twin, and are no more genetically alike than traditional siblings.
All troop members assist mothers with caring for the young, including adult males, subadults, and juveniles. As an example, males will pick up and carry infants to the mother during feeding time, rather than leave them crying on their own. After feeding from their mothers until the age of one month, infants will begin to eat solid foods. Gradually, as their appetite and strength increase, they become fully weaned around the age of three or four months.
Both males and females reach sexual maturity around the age of two years old.
As frugivores, moustached tamarins consume a large portion of fruit in their daily diets. This fruit consumption leads to the dispersal of seeds, therefore making them natural seed dispersers.
A seed disperser is an animal that plays a role in moving plant seeds away from the parent plant, which is critical for plant reproduction. Primates are often referred to as endozoochory agents, meaning they disperse seeds by ingesting them and then defecating them at a different time and place. By moving seeds away from the parent plant, moustached tamarins reduce a plant’s need to compete with others for resources such as nutrients, sunlight, water, space, etc. This then allows plants to establish themselves and contribute to forest regeneration and species diversity.
The International Union for Conservation of Nature lists moustached tamarins as Least Concern (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
According to the IUCN Red List of Threatened Species, there are no major threats to this species, although they are sometimes used as pet animals or model animals for biomedical research.
The moustached tamarin is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
Across Brazil and Peru, the following conservation areas protect moustached tamarins: BrazilSerra do Divisor National Park, Abufarí Biological Reserve, La Reserva Nacional Matsés, etc. Although they do not face immediate threat, moustached tamarins are still monitored throughout their geographic range for potential changes in their status.
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Written by Brooklynne Mitchell-Arno, April 2025