Like many primates, Geoffroy's marmoset is a gregarious, social animal, and typically lives in family groups of eight to ten individuals, consisting of the dominant female, her mate and their offspring, with breeding usually restricted to the dominant pair (2) (5) (6). Young remain within a group, even when adult, and help care for their siblings. These 'helpers' gain valuable breeding experience, which may be used when suitable habitat becomes available for them to establish their own territory, as part of a dominant, monogamous breeding pair (5). Dominance is enforced by scent-marking, scolding, cuffing and eye command. This is accentuated in the female by pheromones produced in her scent glands, which inhibit ovulation in subordinate females, preventing them from breeding as long as they remain within the group (6). The dominant female typically gives birth to twins, although singletons and triplets also occur, after a gestation period of around 140 to 148 days (2) (5) (6). The father carries the young, which are completely dependent for the first two weeks (5) (6). After this, all members of the group take turns in carrying. Infants are weaned and independent by five to six months, by which time they are capable of collecting their own food (6). Sexual maturity is reached at about 15 to 18 months of age (6), and individuals live around 10 years (5). These diurnal, arboreal animals spend the day roaming around territories that may be up to 5 hectares in size, and sleep at night in tree holes or other shelters. Home ranges are overlapping and, although they are not defended, they are marked using scent, which is often smeared around favourite gum holes in trees. The diet includes plant gums and saps, nectar, fruit, insects, invertebrates and other small animals (5). This species has also been known to follow swarms of army ants, which flush many organisms up towards the trees, making them available for the marmosets (8).

Geoffrey's marmoset is an exceptionally distinctive monkey, most readily recognised for its conspicuous white cheeks, forehead and throat, which contrast starkly against its elongate black ear-tufts, tan to black face, and dark coat (2). The body is greyish-black mottled with yellow-orange on the upperparts, brown on the underparts, and the long black tail is lightly ringed (2) (4). Like all marmosets, Geoffroy's marmoset has incisor teeth that are specially adapted to carving out small holes in the trunks of trees, through which they drink the sap and gum that oozes out, which are an important food source (5).

Geoffroy’s Marmoset occurs in the state of Espírito Santo and the forested eastern and north-eastern part of Minas Gerais, north as far as the Rios Jequitinhonha and Araçuaí and south to near the state border of Espírito Santo and Rio de Janeiro (Ávila-Pires 1969; Hershkovitz 1977; Coimbra-Filho 1984; Rylands et al. 1988). The populations just south of the Rio Jequitinhonha resulted from animals released near its mouth, at Belmonte, around 1975 (Coimbra-Filho 1986c). From there it spread eastward, and today also occurs in gallery forests throughout the region of dry thorn scrub (caatinga) of the middle reaches of the river (Rylands et al. 1988). Vivo (1991) limits it to the east of the Serra do Espinhaço in Minas Gerais. It has been recorded from the eastern slopes of Serra do Cipó, a southerly section of the Serra do Espinhaço range, at an altitude of 1,274 m (Oliveira et al. 2003). Hybrid populations of C. penicillata and C. geoffroyi have been observed in some parts of the Serra da Piedade along the Rio Piracicaba, affluent of the upper Rio Doce, where the Atlantic coastal forest gives way to the cerrado (Coimbra-Filho et al. 1993; Passamani et al. 1997). The range of C. geoffroyi overlaps with C. flaviceps (see below) in southern Espírito Santo (south of the Rio Doce) and south-eastern Minas Gerais. However, C. geoffroyi is generally restricted to lowland areas, below 500–700 m, and C. flaviceps to altitudes above 400–500 m (Coimbra-Filho 1971; Coimbra-Filho et al. 1981). Hershkovitz (1977) asserted that the highest recorded locality for C. geoffroyi is Santa Teresa, 659 m above sea level, but Mendes (1993, 1997a) has observed mixed bands of C. geoffroyi and C. flaviceps at altitudes of 800 m. Hybrid populations have been recorded for intermediate elevations (Mendes 1993, 1997a).

Geoffroy's marmosets (Callithrix geoffroyi) are found in southeastern Brazil. They inhabit the state of Espirito Santo and the forested eastern and north-eastern part of the state of Minas Gerais. They are found as far north as the Rio Jequitinhonha and Aracuai and south to near the state border of Espirito and Rio de Janeiro. The population south of Rio Jequitinhonha originated from animals released near the river's mouth in 1975. This population has since spread eastward. A hybrid population of Callithrix penicillata x C. geoffroyi has been found in the Serra da Piedade along the Rio Piracicaba.

Biogeographic Regions: neotropical (Native )

Restricted to small fragments of Atlantic rainforest in East-Central Brazil (Bahia, Espirito Santo and Minas Gerais states) (4) (6).

Geoffroy's marmosets are small primates, only about 200 mm in length, with a tail of about 290 mm. Females tend to weigh around 190 g, while males range from 230 g to 350 g. The body is predominately dark or blackish brown. The tail is ringed with gray and black bands. Adults have white foreheads, cheeks, temples and throats. Adults also have tufts of black fur in front of their ears. Juveniles differ from adults in that they lack both the ear tufts and white markings around the face. Juveniles begin to grow their ear tufts at an age of about 2 weeks, and have full adult markings by the age of 5 months.

Range mass: 190 to 350 g.

Average length: 198 mm.

Sexual Dimorphism: male larger

Habitat and Ecology

Systems

• Terrestrial

Geoffroy's marmosets inhabit secondary lowlands and sub-montane forest, evergreen, and semideciduous forest, forest edge and dry forest patches. They are generally found at an elevation of between 500 and 700 m, but can be found as high as 800 m.

Range elevation: 500 to 800 m.

Average elevation: 600 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

Found in lowland tropical and subtropical rainforest, frequently where there is secondary growth (1) (7) (8).

Geoffroy's marmosets are omnivorous, eating mostly fruit, insects, and plant gums. They also eat flowers, nectar, frogs, snails, lizards, and spiders. These small primates are able to gouge into tree trunks, branches, and vines to obtain gum.

Animal Foods: amphibians; reptiles; insects; terrestrial non-insect arthropods; mollusks

Plant Foods: fruit; nectar; flowers; sap or other plant fluids

Primary Diet: omnivore

Geoffroy's marmosets prey on a variety of small vertebrates and invertebrates and provide prey for larger predators.

Members of the Family Callitrichinae, including Geoffroy's marmosets, are highly affected by predation, perhaps to the highest degree of any primate. Field reports indicate that monitoring for predators is a high priority in the lives of marmosets. Groups of C. geoffroyi respond to predator threats by increasing rates of vigilance and decreasing rates of play and foraging. Members of groups share the task of monitoring by rotating occupation of the best look-out point. Geoffroy's marmosets have a variety of responses to raptors, snakes, and felids as well as other predators. Wild Geoffroy's marmosets react to predators with combinations of monitoring, alarm calls, mobbing, fleeing, and freezing.

Known Predators:

• raptors (Falconiformes)
• snakes (Serpentes)
• cat species (Felidae)

Geoffroy's marmosets make alarm calls when they perceive a threat. They have also been observed scent marking. Allogrooming has been observed too, and is thought to contribute to calming the group down after a threat has passed.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Geoffroy's marmosets generally live about 10 years.

Typical lifespan

Status: wild: 10 (high) years.

Maximum longevity: 17.6 years (captivity)

The dominant male and female in each group of Geoffroy's marmosets form a monogamous pair bond. Only this pair will breed. Dominant behavior of the breeding female will halt ovulation in other females in the group. This process may be aided by pheromones produced in the scent glands of the dominant female. As a result, subordinate females cannot reproduce while they remain with the group. Such hierarchy is less evident among males. Usually only one male mates with the breeding female, but polyandry (usually rare among mammals) has been observed under certain circumstances.

Pre-copulatory courtship usually begins with sniffing each other's muzzles and genitalia, as well as marking objects, licking, grooming and huddling. These behaviors are also seen in post-copulatory courtship. These behaviors increase as the female reaches estrus.

Mating System: monogamous ; polyandrous ; cooperative breeder

Female estrus cycles vary from 14 to 21 days. Should a female become pregnant, the gestation lasts about 140 to 148 days. Parturition may take up to an hour. Usually twins are born, but sometimes singletons or triplets occur. The male will assist with the birth by licking the babies before giving them to the mother. Other family members may help to eat the placenta. Post-partum estrus occurs 2 to 14 days after giving birth. Young are weaned by 5 or 6 months and reach sexual maturity between 15 and 18 months.

Breeding interval: There are usually 150 to 152 days between births in Geoffroy's marmosets.

Breeding season: Geoffroy's marmosets breed year round.

Range number of offspring: 1 to 3.

Range gestation period: 140 to 148 days.

Range weaning age: 5 to 6 months.

Range age at sexual or reproductive maturity (female): 15 to 18 months.

Range age at sexual or reproductive maturity (male): 15 to 18 months.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; post-partum estrous

A female Geoffroy's marmoset will suckle both of her twins at the same time, until the young are weaned. For the first week after young are born, the father carries the babies exclusively. After this, the male will still be the primary carrier, but all members of the family participate in carrying the young. Older siblings assist in the rearing of the younger siblings, by which they learn skills essential to raising their own young in the future. Females primarily provide milk for their young.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

Geoffroy's marmosets are considered "Least Concern" by the International Union for Conservation of Nature. The population trend for this species is classified as stable. However, widespread destruction is causing their populations to decline. The range of C. geoffroyi was once throughout the Brazilian Atlantic forest, but only about 1% to 5% of this habitat remains. For example, less than 6.8% of the Atlantic forest remains in the state of Minas Gerais. However, C. geoffroyi is considered relatively abundant and inhabits many protected areas. For this reason, their rate of population decline does not warrant a threatened listing. In 1982, Russell Mittermeier recommended that C. geoffroyi be listed as endangered, but studies conducted in 1991 found them to be locally abundant, if patchily distributed. In 1994, 1996, and 2000 C. geoffroyi was listed as vulnerable by the IUCN. Today, it is not considered under serious threat.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Classified as Least Concern (LC) on the IUCN Red List (1), and listed on Appendix II of CITES (3).

Population

Population Trend

Major Threats

Geoffrey's marmoset has declined in numbers as a result of habitat destruction, capture for the pet trade, for exportation to zoos and for biomedical research, and persecution due to an assumption that they carry yellow fever and malaria (5) (6). Today, habitat destruction poses the greatest threat to this rare primate, which has left it restricted to small forest fragments (5) (6).

Conservation Actions

Conservation measures are unknown.

There are no known adverse effects of Geoffroy's marmosets on humans.

Geoffroy's marmosets are occasionally captured for the pet industry.

Positive Impacts: pet trade