BUFFY SAKI

Pithecia albicans

Geographic Distribution and Habitat
The buffy saki (Pithecia albicans), also known as the white-footed saki, is one of the least-studied neotropical primates. Endemic to western Brazil, south of the Amazon, buffy sakis were once thought to be restricted to a relatively small area in Brazil between the lower Rio Purus and Rio Tefe south of Rio Solimoes-Amazonas. However, additional primate surveys have shown that they extend to the east bank of the lower Rio Jurua, Amazonas (Rio Yurua). They also occur along Rio Bauana, a tributary of the Tefe River.

All Pithecia species prefer mature forests that includes white-water flooded forest (forest-varzea), black-water flooded forest (igapo), palm swamp, and terra firma forest. Although they can be found in disturbed habitats, fragmented forests, and secondary forests, they choose to inhabit mature forests due to higher densities of seeds and tree species. Like other sakis, buffy sakis live in subtropical and tropical moist lowland forests.

Buffy saki range, IUCN 2019

Size, Weight, and Lifespan
The head-to-body length of an adult male buffy saki is 15–18 in (40.4–56 cm). Female head-to-body length is 14–21 in (36.5–54 cm). Adults weigh, on average, about 5 lbs (2.3kg), with males weighing up to 6.6 lbs (3 kg).

Not much is known about the lifespan of buffy sakis; however, similar saki species have been known to live to about 15 years in the wild. Some sakis in captivity have lived to be 36 years old.

Appearance
Buffy sakis are characterized by their long, coarse, fluffy hair. Their hair is mainly white or cream colored, with brownish black colored hair extending from their elbows to their wrists. Their tail is entirely black. Small patches of brown or black hair are also noticeable on their hind limbs, and from the nape of the neck to tail. Their hands and feet, however, remain white or cream colored. The hair on their tail and trunk are longer than those on the forearms and hind limbs. Their underbellies are very lightly covered in hair. The hairs on the crown of their head are directed forward like a hood and sometimes overlap the facial region, making it look like they have bangs.

Male and female buffy sakis are sexually dimorphic in color—also known as sexual dichromatism. Males’ facial skin is mostly black with small pinkish skin patches above their eyes and distinct white-to-cream eyebrows and cream upper lip hairs. Females’ facial skin is also black with cream-to-white eyebrows, but with white or cream-colored malar stripes (from the base of their mouth to the side of their neck) that extend out to the cheeks. Older females have more white covering their face than juveniles or subadults.

Adult males and females also have large scent gland patches on their throat, which are ringed with a light orange color. The orange ruff is more prominent in males.

When approached in the wild, the hair easily piloerects or “puffs up” as a threat. This tends to make them look bigger than they actually are. The length of the tails of buffy sakis are equal to their body length. Their tails are not prehensile, but the hair on the tail does “puff up” when approached or if they feel threatened.

What Does It Mean?

​​Diurnal:
Active during daylight hours.

Fission-fusion society:
A society in which the members of a social group break off into smaller groups and then rejoin as a larger group.

Monogamy:
A mating system in which a male and female mate exclusively with each other.

Pericarp:
The walls of a ripened fruit.

Piloerection:
Erection or bristling of hairs due to the involuntary contraction of small muscles at the base of hair follicles that occurs as a reflexive response of the sympathetic nervous system especially to cold, shock, or fright. Causes hair to stand on end, giving the illusion of a larger, more formidable body size.

Sexual dichromatism:
When male and female animals of the same species display different coloration.

Visit the Glossary for more definitions

Photo credit: Nayeryouakim/Creative Commons

​Diet
Buffy sakis are is primarily frugivorous. Seeds and nuts constitute a large portion of their diet as well. During the dry season, when fruit is not plentiful, they may consume leaves and insects. The fruit that they consume has hard pericarps, which is the layer of tissue that surrounds the seeds, also known as the fruit wall. Their robust incisors and canines help break through the tough parts of fruit and seeds. On average, saki monkeys spend around 95% of their waking time eating and breaking open seeds.

Behavior and Lifestyle
Sakis are dirunal monkeys, spending most of the day in the trees and only rarely descending to the forest floor. Their day range (the distance a group or individual moves in a day) is roughly one mile (1.5–2 km). Their home ranges (the area they stay within during a set period of time, such as a year) can extend from just over 6 miles to just over 15 miles (10–25 km). The buffy saki moves through the forest quadrupedally, mainly walking and running, climbing, and leaping. This species has been known to “bounce” when moving, which is caused by the propulsion of all four limbs.

Even though buffy sakis can be shy and cautious primates, they are very territorial and defend their territory from intruding groups. Duet vocalizations between males and females are important for maintaining these boundaries as well as social bonds. Buffy sakis mark their territory with their scent glands by rubbing on trees and urine washing.

Daily Life and Group Dynamics 
In general, saki monkeys live in family groups that consist of parents and their offspring, with mated pairs usually forming lifelong pair bonds. Buffy sakis are similar, forming small groups (about 2–6 individuals), which come together and form larger congregations. These groups are described as closed social units. In some species this may resemble a loose fission-fusion society. Groups move early in the morning and early afternoon. They can spend up to 9 hours on the move.

Juveniles may stay with their parents for up to a year or two after the birth of the next infant. Males and females teach each other how to raise the young by grooming, feeding, or watching after them. Sometimes a group member will carry another members’ infant.

Fun Facts

While eating, buffy sakis take as much food as possible into their hands, fingers, and toes and eat quickly while scanning the area for more.

Buffy sakis suspend downward from tree branches, holding on with their hind limbs while eating fruits and seeds.

Communication
Duetting between the male and female is important in maintaining territorial boundaries and social bonds between pairs. Territorial calls are often loud shrills.

Adults mark their territory with urine and with secretions from their gular gland (which is near the throat). Males tend to mark more trees than females. 

Other forms of communication can be seen, such as branch and body shakes, piloerection, and chasing to threaten and displace another group member. These are all used in agonistic interactions.

Reproduction and Family
Reproductive habits in the buffy saki are not well known, so their breeding season is not clearly defined. However, some scientists suggest that they breed in the spring. Buffy sakis are known to participate in monogamy.

Males reach maturity around 32 months of age; females can take several more months. Male saki monkeys make calls to the females during mating season. Most of the time sakis are considered a monogamous species; however, studies in Venezuela revealed that some saki species are not.

Females give birth once a year—typically to one offspring—and are the predominant caregivers. Saki infants stay attached to their mother’s thigh from birth to about 1 month old. From one to four months of age, the young shift to a dorsal position. Once the infant is around 5 months old, the mother stops carrying him or her. Mothers feed, protect, and nurture their young until they are ready to be on their own. If the infant has siblings from the previous year or two, they help care for the newborn. Adult males have been observed grooming the young as well.

Ecological Role
With seeds and fruits being a large part of the buffy sakis diet, they are contributors to seed dispersal. As they travel through the forest and the seeds pass through their digestive system, the seeds may be dispersed over a mile from the parent tree. This provides a more diverse forest, creating a stronger ecosystem.

Conservation Status and Threats
The International Union for Conservation of Nature gives the buffy saki a Least Concern status (IUCN, 2015). Distribution of the buffy saki is not well known; however, like all saki monkeys, they are threatened by hunting and habitat destruction throughout their range. They are found in the pet trade and occasionally hunted for decorative ornamentation on clothing and hats.

Conservation Efforts
Currently the buffy saki is not present in any protected areas in Brazil, but they are sometimes found in captivity, such as at the Sao Paulo Zoo and Rio de Janeiro Primate Center. They are listed on Appeddix II of the Convention on International Trade in Endangered Species (CITES), which means that trade must be regulated so that they do not become threatened in the future.

In order to determine the best conservation actions for the buffy saki, more research is needed on their population size, trends, and distribution.

​References:

  • https://www.iucnredlist.org/species/41567/17972299
  • http://www.theprimata.com/pithecia_albicans/
  • Marsh LK. A Taxonomic Revision of the Saki Monkeys, Pithecia Desmarest. 1-163. 
  • Peres CA. 1993. Notes on the Ecology of Buffy Saki Monkeys (Pithecia albicans, Gray 1860): A Canopy Seed-Predator.  American Journal of Primatology. 31:129-140. 
  • Soini, P. 1986. A Synecological Study of a Primate Community in the Pacaya-Samiria National Reserve, Peru. Primate Conservation Vol. 7, 63-71.

Written by Tara Covert, November 2019