Saguinus graellsi was previously recognized as a subspecies of Saguinus nigricollis, S. n. graellsi.
Graell’s tamarins make a long call audible to humans that travels 150 to 200 m, made up of 2 to 30 notes. The call is different between species, populations, and individuals. Within a group, the construction of the long call may reflect social status. Calls function to keep the social group together and to regulate space between neighboring groups. Graell’s tamarins also have many other calls, including alarm calls when a group member sees a raptorial bird, squawking calls amongst young when seeking food from group members, and harsh atonal calls to communicate aggression. Infants chatter and use calls incorrectly, seeming to learn from group members as they age. Olfaction is another important component of communication. Scent glands are found around the genitals (anogenital or circumgenital glands), lower abdomen (suprapubic glands), and sternum (sternal gland). The glandular secretions, a mixture of fatty acids, esters, proteins, and other organic compounds, communicates information about species, sex, reproductive state, and individual identity. The secretion may be mixed with urine and applied to aspects of the environment (branches, trunks, and lianas) with habitual rubbing motions. Depending on the secretion, it is called anogenital, suprapubic, or sternal scent marking. Adult females scent mark more than adult males. Graell’s tamarins also use physical signals of communication. Arousal is signified by raised hair on the head, ears, shoulders, or whole body. Facial expressions denoting aggression include frowning, opening of the mouth, and shaking of the head.
All males and one-third of females have dichromatic vision; remaining females have trichromatic vision. While the gene for short wavelength vision is not sex-linked, the genes for medium and long wavelength vision are recessive and located on the X chromosome. It is believed that dichromatic vision enables better detection of camouflaged prey and predators, while trichromatic vision enables better detection of ripe, colorful fruits.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: pheromones ; scent marks
Perception Channels: visual ; infrared/heat ; tactile ; acoustic ; chemical
In 2008, the IUCN Red List considered S. graellsi near threatened, stating that the species almost qualifies as threatened and its population is continuing to decline. The severe deforestation of its western Amazon home is considered the cause of this diminishing population. The IUCN estimates that over the next three generations, approximately 18 years, population size will decrease 20% to 25%. Graell’s tamarins were previously considered a subspecies of black-mantled tamarins (Saguinus nigricollis). In 2003, Graell’s black-mantle tamarins (Saguinus nigricollis graellsi) were rated “least concern” on the list. CITES does not list Saguinus graellsi in its appendices (as a separate species or as a subspecies of Saguinus nigricollis) as a trade-restricted species.
US Federal List: no special status
CITES: no special status
Although believed until the 1970's to be carriers of malaria and yellow fever, S. graellsi probably do no harm to humans.
Humans benefit from the seed-dispersing ecosystem role of S. graellsi.
Graell's tamarins play an important role in seed dispersal. They swallow seeds up to 1.5 cm long and pass them through their digestive tract in 1 to 3 hours, depositing them away from parent plant. Their digestive processes don’t harm the seeds. Though they appear to swallow the seeds because it is difficult to separate the fruit pulp from them, it has been suggested that swallowing such large seeds helps dislodge intestinal parasites.
Ecosystem Impact: disperses seeds
Commensal/Parasitic Species:
Graell’s tamarins spend 25% to 30% of their active time searching for food. Primarily frugivores, they feed on fruits, flowers, nectar, plant exudates, insects, and small vertebrates. When available, small sweet fruits make up the majority of their diet, especially those from the genera Pourouma, Ficus, Cecropia, Inga, and Miconia. Plant exudates like sap, gums, and resin are also eaten, though unlike short-tusked callitrichids, the long-tusked S. graellsi is unable to gouge trees to stimulate the flow of exudate. They consume exudates available through holes bored by insects or from wind damage. During seasonal fruit shortages, Graell’s tamarins increase their intake of nectar and gum to compensate. Animal prey includes frogs, snails, lizards, and insects - particularly grasshoppers, beetles, and stick insects. They also eat baby birds and probably eggs.
Animal Foods: birds; amphibians; reptiles; eggs; insects; terrestrial non-insect arthropods; mollusks
Plant Foods: fruit; nectar; flowers; sap or other plant fluids
Primary Diet: herbivore (Frugivore )
Saguinus graellsi, commonly known as Graell’s tamarin, is native to the upper half of the Amazon between the Napo River and the Pastaza River. It is found in Colombia, Ecuador, and Peru.
Biogeographic Regions: neotropical (Native )
The habitat of S. graellsi includes tropical rain forest, secondary forests that have regrown following a natural disturbance to the rain forest, forest patches within savanna, and along river-edge forests around Amazonian tributaries.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Other Habitat Features: riparian
In the wild, the lifespan of S. graellsi is unknown, but in captivity they have lived 7 to 16 years.
Typical lifespan
Status: captivity: 7 to 16 years.
Graell’s tamarins have fine silky pelage and, unlike many other tamarins, are uniformly colored. The head, neck, mantle, and forelimbs are black to blackish brown. The crown is pale brown and the tail is black except for a brownish basal portion. The area surrounding the mouth has short white hairs. Infants are born with very short pelage. Adults weigh 225 to 900 g, and the length of their head and body is 175 to 310 mm. Tail length is 250 to 440 mm. Their prehensile tails are always longer than the combined length of their head and body, and their legs are longer than their arms. Graell’s tamarins have claw-like nails on all digits with the exception of the hallux, which has a flat nail. The hallux is opposable, but the pollex is not. On each side of the upper and lower jaws there are two incisors, one canine, three premolars, and two molars, which gives them a total of 32 teeth. Saguinus graellsi is considered a long-tusked callitrichid because the canines are longer than the incisors. Moderate sexual dimorphism exists within this species, with females larger than males.
Range mass: 225 to 900 g.
Range length: 175 to 310 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Sexual Dimorphism: female larger
Predators include raptorial birds such as Guianan crested eagles, ornate hawk eagles, and bicolored hawks, snakes such as anacondas, rainbow boas, and jararacas, and tayras. Ocelots may also be predators of tamarins – tamarin hairs have been found in their feces. The response of Saguinus graellsi to predators includes alarm calling, escaping, and hiding. If caught in a tree without anywhere to hide, Graell’s tamarins may drop suddenly to the ground. Once a predator is detected, group members often surround and harass it while emitting specific vocalizations. At least one group member is constantly on guard to prevent surprise attacks by predators and they sleep surrounded by thick foliage to camouflage themselves.
Known Predators:
Saguinus graellsi has a monogamous mating system and only the dominant female and dominant male mate. Fertile ovarian cycles are stifled in the rest of the social group’s females by a combination of the dominant female’s behavioral domination as well as the effects of pheromones exuded by her scent glands. It is also suggested that subordinate females have an active part in determining whether or not they will breed. If a subordinate female does give birth, the dominant female may practice infanticide. Subordinate females may gain breeding experience during this time. Eventually subordinate females form their own groups or join a new social group, then becoming a dominant female and breed.
Mating System: monogamous ; cooperative breeder
Females do not exhibit external signs of estrus. Males are reported to associate with females more closely during the receptive period of the estrus cycle. Graell’s tamarins are able to give birth twice a year. In one study of Graell's tamarins (De La Torre et al., 2005) 40% of females they observed experienced a second birthing peak. Gestation lasts 130 to 170 days. Peak birthing season occurs in January, and the second peak birthing season is in June. Births occur at night. All Graell’s tamarins have dizygotic twins, which weigh 25 to 50 g at birth – up to 20% of the mother’s weight. With the exception of tarsiers, they are proportionally the heaviest infants among primates. Young begin to explore around 21 days of age, but still ride on their parents’ backs until they are six or seven weeks old. At four weeks infants begin to eat soft, solid foods. At 10 weeks, the young are independent. They reach puberty between 12 and 18 months.
Breeding interval: Graell’s tamarins breed once to twice a year.
Breeding season: Breeding occurs during the early to mid wet season of the Amazon lowlands.
Range number of offspring: 2 to 2.
Range gestation period: 130 to 170 days.
Range weaning age: 4 to 10 weeks.
Average time to independence: 10 months.
Range age at sexual or reproductive maturity (female): 12 to 18 months.
Range age at sexual or reproductive maturity (male): 12 to 18 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; post-partum estrous
Fathers assist in birth, receiving and cleaning the newborn. Other adult group members may also help. Born helpless, infants hang on to their mother or father with their hands and feet. Fathers hold the young except during feeding. He gives the infant to the mother every two to three hours and feeding lasts about half an hour. The young feed exclusively on milk for four weeks, then soft foods are introduced and weaning is complete by ten weeks. Help from the male parent is considered a key adaptation in the high reproductive rate of tamarins. Once females become established as the dominant breeding female they have the highest reproductive rate of any other primate. Both parents and all members of the social group help carry infants and give bits of food to young, as well as providing protection and education.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning
Graells's tamarin, Leontocebus nigricollis graellsi, is a subspecies of the black-mantled tamarin from the northwestern Amazon in southeastern Colombia, eastern Ecuador and northeastern Peru.[3][4] It differs from other black-mantled tamarins in having a dull olive-brown (no reddish-orange) lower back, rump and thighs.[5][6] However, molecular genetic analysis does not support treating Graell's tamarin as a separate species from the black-mantled tamarin.[3]
Graells's tamarin, Leontocebus nigricollis graellsi, is a subspecies of the black-mantled tamarin from the northwestern Amazon in southeastern Colombia, eastern Ecuador and northeastern Peru. It differs from other black-mantled tamarins in having a dull olive-brown (no reddish-orange) lower back, rump and thighs. However, molecular genetic analysis does not support treating Graell's tamarin as a separate species from the black-mantled tamarin.
