Callithrix chrysoleuca
gold-and-white marmoset

Gold-and-white marmosets (Callithrix chrysoleuca) are found in a small area in the Brazilian Amazon. Their range extends between the Rio Amazonas and the south bank tributaries of the Urariá-Canumã. (Macdonald, 2001; Wilson and Reeder, 2005)

Gold-and-white marmosets live in the tropical rainforests of the Amazon. They are found in the upper levels of the rainforest canopy. (Macdonald, 2001)

Males and females of Callithrix chrysoleuca are monomorphic. Like many other marmosets and tamarins, gold-and-white marmosets have tufts of fur that set them apart from other primates. The tufts are comprised of long white hair and are located on the ears. Their coat is pale yellow to orange in coloration. The face is pink. In this species, as in other marmosets and tamarins, claws replace nails on most digits, supporting their scansorial mode of locomotion. Gold-and-white marmosets do not have opposable thumbs; this is also true of other marmosets and tamarins, but is unlike most other primates. The body length ranges from 19 to 26 cm, while the tail can reach 30 to 36 cm. Weight is not known for Callithrix chrysoleuca but other members of the subfamily Callitrichinae range from 300 and 450 grams. (Jimenez I and Jiméne, 2004; Kinzey, 1989; Macdonald, 2001; Wilson and Reeder, 2005)

Although not much research has been done on the mating system of gold-and-white marmosets, it is likely to be similar to that of other members of the subfamily to which it belongs, Callitrichinae. Callitrichine mating systems have been described as monogamous, polyandrous, polygynous, and polygynandrous. Mating systems vary among populations and genera. All four mating systems can be found in one social group of Callithrix chrysoleuca. It has been hypothesized that mating system variability in these animals is due to the high rate of twinning and relatively large size of newborns. (Digby, et al., 2007; Kinzey, 1989)

Alloparenting and allogrooming are also observed in callitrichines. Mating status does have some effect on rate and direction of allogrooming. Breeding males and females receive more grooming than other members of the group. Non-breeding females as well as non-breeding males are observed copulating, which can make it hard to determine which mating system is most common in Callitrichinae. (Digby, et al., 2007; Kinzey, 1989)

Research on reproductive behavior has not been done on gold-and-white marmosets. Other members of the subfamily Callitrichinae breed year round due to the abundance of gum, which is a staple in their diet. After mating, females have a gestation period of from 130 to 170 days. Females almost always give birth to twins. Twins make up roughly 19 to 25 percent of their mothers weight at birth. This is rare for Primates and can explain the cooperative breeding strategy that marmosets use. The rearing of young is shared by members of the group and the young will begin to be weaned at around 2 months old. Young will reach sexual maturity between 12 and 18 months but will not reach adult size for another year. (Kinzey, 1989; Macdonald, 2001)

Although not much information is known on parental investment in gold-and-white marmosets, there is some information from other species in Callitrichinae. When females give birth, it is usually to a set of twins. From birth, both mothers and fathers care for the young. (Digby, et al., 2007; Kinzey, 1989)

Alloparenting is seen in species of Callitrichinae. There are many possible explanations for this, including the small size of the mother, and the fact that males through courtship ensure they will breed again. It is also observed that the more experience a juvenile has in carrying infants, the better his/her chances of breeding successfully in the future. Alloparenting allows young to learn how to interact socially with the group from grooming to play and other social activities. The parents provide everything from food to protection from predators. (Digby, et al., 2007; Kinzey, 1989)

The longevitity of gold-and-white marmosets is unknown in the wild as well as in captivity. In captivity, other species of marmoset are known to live anywhere from 7 to 16 years. (Macdonald, 2001)

Gold-and-white marmosets are very social, as are other Callitrichinae species. They live in large extended family groups usually containing anywhere from 8 to 20 individuals, depending on the availability of food sources. Marmosets usually live in larger groups than tamarins due to their ability to eat tree gum. There is a dominance hierarchy in the group; it is not known how the hierarchy is determined. Allogrooming plays an important role in their social structure, as is true for most other primates. These animals live mostly in the trees and only come to the forest floor on occasion to forage or move to another tree. They spend the majority of their day foraging around their territory as well as participating in social activities. As with many other primates, gold-and-white marmosets like to play with one another, especially when they are young, but this remains an important aspect of life into adulthood. (Digby, et al., 2007; Kinzey, 1989; Macdonald, 2001; Wilson and Reeder, 2005)

Home range size is not known for Callithrix chrysoleuca. In other callitrichines, territory size may be anywhere from 100,000 to 400,000 square meters. These animals travel over about one third of their territory in a day in search of food and in order to protect it from other animals. (Macdonald, 2001)

There is no information on communication in gold-and-white marmosets, but a related species, Saguinas oedipus, uses acoustic communication mostly as well as visual displays and scent markings. This species uses calls to inform each member of its group about predators, food sources, and intruding groups of tamarins. Visual displays are used to express dominance and in intergroup challenges that occur where territories overlap. An individual may puff its hair, display its rump as well as white genitalia, and raise its tail. Chest-rubbing and sprawling are used for territorial purposes as well as to express the dominance of certain individuals in a group. Individuals sometimes enforce their scent on other group members by urinating in a tree hole that has been made to extract gum. This ensures that other group members will encounter their scent. (Digby, et al., 2007; Macdonald, 2001)

Gold-and-white marmosets feed mainly on exudates from plants, primarily gums, but some saps as well. They have specializations that allow for this type of diet, including elongated, chisel-like lower incisors as well as a wide jaw. Both of these specializations allow gold-and-white marmosets to penetrate the bark of gum producing trees, which causes the tree to excrete the gum or sap they are searching for. Although tree gum is a staple in their diet, they also eat other foods such as seeds, fruits, nuts, and some insects and small vertebrates. (Digby, et al., 2007; Macdonald, 2001)

Information is not currently available on the predators of gold-and-white marmosets, although they are probably eaten by a variety of rainforest carnivores. The related species, Callithrix flaviceps, makes more warning calls at higher levels of the canopy, which is believed to be in response to avian predators. Gold-and-white marmosets are vulnerable to avian predators and avoid predation by staying just below the rainforest canopy. In addition, these animals are very good at maneuvering among the trees, which can serve to their great advantage in escaping less agile predators. (Digby, et al., 2007)

Gold-and-white marmosets help to disperse seeds and serve as prey for a small number of rainforest carnivores. (Digby, et al., 2007)

Gold-and-white marmosets have no known positive economic importance to humans, aside from their roles in the healthy, native ecosystems they inhabit. They may attract ecotourism interest.

Callithrix chrysoleuca causes no known economic problems for humans.

The largest threat to gold-and-white marmosets is habitat destruction. With the alarming rate at which rainforests are being cut down each year, these animals are quickly losing their habitat. Conservation and education efforts to inform the public about rainforest flora and fauna have been the most effective means for helping gold-and-white marmosets survive. (Macdonald, 2001)