Pithecia monachus

Geographic Range

Also known as Pithecia hirsuta , Pithecia monachus can be found in northwestern Brazil, Colombia, Ecuador and Peru (Nowak, 1999). Members of this species occur in the Colombian trapezius north of the Amazon, and extend from north of the Putumayo River to the southern bank of the Yari, Caqueta and Orinoco rivers. The range of Pithecia monachus is limited to the upper elevations of well-developed rain forests of these regions (Hernandez-Camacho and Cooper, 1976).

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Arboreal, high canopy dwellers. They are very nervous around humans and disturbance, thus very little data has surfaced on the lifestyle of P. monacha . However, scientists agree that the tallest trees available (from 10-35 meters tall) are the habitat of choice for these animals, and in most instances they are the sole primate inhabiting this niche.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Sakis are characterized by their small size of 30-50 cm and very heavy, thick and nonprehensile tail which adds 25-55 cm to their body length (Nowak, 1999). The face of the monk saki is partly bald but bearded with a hood of curly black hair covering the forehead. The nostrils are laterally positioned on the face (Flannery 2004). Sakis are generally black, but their hands and feet are light in color.

The skull morphology is distinctive: the orbits are separated from the brain case by a frontal depression. The incisors are forward-facing, long canines are present and used to break the hard skin of fruits. They have quadritubercular molars with deep basins (Seth & Seth, 1986).

The hands are similar to those of Aloutta spp. in that they exhibit a split between the second and third digits (Moynihan, 1976). Each digit has a nail, and the front limbs are shaped for gripping branches after a leap. The hind legs are modified for fast and far leaping. Vision is stereoscopic for an arboreal habitat.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

Reproduction

Adult, monogamous pairs breed for life.

• Mating System
• monogamous monogamous

Pairs raise a maximum of a single offspring per breeding season. Monk sakis typically retain a family group size of 4.5 individuals on average. Females are in estrus for approximately 18 days, and after conception members of this genus gestate for approximately 170 days (Nowak, 1999).

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Young cling to female's belly when young, and then move to her back as they approach weaning age (Britannica, 1981).

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• extended period of juvenile learning

Lifespan/Longevity

Behavior

All species of Pithecia are diurnal. The monk sakis are quadrupedal leapers. They are skittish and shy. Family groups are nuclear families consisting of a monogamous pair with its offspring. These families raise offspring in defended territories, similar to gibbons in the genus Hylobates . A peculiar behavior is observed at night when several families sleep in the same tree. The adults recognize their mate by highly specialized vocalizations; acoustic signals including squeaks, whistles and trills are used for low intensity aggression. Barks and grunts constitute a higher level of aggression, and finally, roars are the most extreme aggressive vocalizations. The monk sakis practice extensive allogrooming as a general social behavior which is nonsexual in orientation or motivation.

• Key Behaviors
• arboreal arboreal
• scansorial
• saltatorial saltatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social

Home Range

Home range differs by gender: males travel in a 50 ha area, while the females utilze only 33.5 ha.

Communication and Perception

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

The diet of the monk saki is frugivorous but also includes seeds, nuts, and some insect material. They have also been documented to prey on bats (Moynihan, 1976; Hershkovitz, 1977). They use their large canines to break their food before ingesting it. The monk saki's high quality diet restricts their range in that they must be able to sequester enough high-protein food for their immediate family group (Terborgh, 1983).

• Primary Diet
• herbivore herbivore
  • frugivore frugivore

• Animal Foods
• mammals
• insects

• Plant Foods
• seeds, grains, and nuts
• fruit

Conservation Status

This species is rated "Least Concern" by the IUCN, as there are still believed to be substantial populuations in the upper Amazon basin. It is listed on Appendix II of CITES, so there are restrictions on international trade of the animals or their parts.

Other Comments

Very little research has been done on Pithecia monacha, perhaps for two reasons: they do not survive well in captivity, and are very difficult to view in the wild, due to shyness and a very high habitat.

Additional Links

Encyclopedia of Life

Contributors

Tara Poloskey (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Dunbar, R. 1988. Primate Social Systems . Ithaca, New York: Comstock Publishing Associates.

Flannery, S. 2004. "Monk Saki (Pithecia monachus)" (On-line). Primate Behavior. Accessed November 03, 2004 at http://members.tripod.com/uakari/pithecia_monachus.html .

Hernandez-Camacho, J., R. Cooper. 1976. The Nonhuman Primates of Colombia. Pp. 35-69 in Neotropical Primates . Washington D.C.: National Academy of Sciences.

Hershkovitz, P. 1981. Living New World Monkeys(Platyrrhini)-With an Introduction to Primates: Volume 1 . Chicago and London: The University of Chicago Press.

Moynihan, M. 1976. The New World Primates . New Jersey: Princeton University Press.

Nowak, R. 1999. Walker's Mammals of the World . Baltimore, Maryland: Johns Hopkins University Press.

Seth, P., S. Seth. 1986. The Primates . New Delhi/Allahabad: Northern Book Centre.

Terborgh, J. 1983. Five New World Primates: A Study in Comparative Ecology . New Jersey: Princeton University Press.

"CITES" (On-line). Accessed October 14, 1999 at http://www.cites.org/ .

1981. Saki. The New Encyclopedia Britannica , Vol. 10.