Buffy Saki, Pithecia albicans
BUFFY SAKI
Pithecia albicans
Geographic Distribution and Habitat
Buffy sakis are only found in Brazil, and their distribution is mainly along the banks of the Rio Solimões in the Amazon Rainforest. They reside in various forest types, from the drier terra firma sections to partially flooded riverine and swamp forests. However, because they live in such wet conditions, buffy sakis spend most of their time in the upper forest canopy, between 82-98 feet (25 – 30 m) high, where the dense foliage shelters them from the rains.
Sakis are one of the least studied Latin American primates. Most of what we know about Buffy Sakis comes from short-term surveys and research conducted in the 1980s and 1990s.
Buffy sakis are sometimes called white-footed or white sakis.
Buffy sakis’ distinct appearance has always distinguished them from other closely related sakis. Initially, taxonomists relied on museum specimens that were poorly documented to determine differences between saki species. Some authors published saki descriptions and classifications without seeing one in the wild or observing captive individuals. Saki taxonomy was revised in 2014, increasing the number of species within the group from five to sixteen separate species.
Size, Weight, and Lifespan
Relative to all monkey species, sakis are medium-sized primates with non-prehensile tails. Buffy sakis are the largest species of the genus. Males and females look similar, though females tend to be slightly smaller on average. Male bodies (head to the base of their tail) measure 20 to 22 inches (50-57 cm), and females 15 to 21 inches (38-54 cm). Both male and female buffy sakis have tails nearly the same length as their bodies, ranging from 16 to 19 inches (40-49 cm). Their weight ranges from 6.6 to 11 pounds (3- 5 kg).
Little is known about the lifespan of wild saki monkeys. Some researchers suspect sakis have a long reproductive window and potentially a longer lifespan than previously thought. One captive saki was reported to be 36 years old. Wild saki monkeys have been observed living for up to 15 years. This lifespan is the most likely estimate for the buffy saki.
Appearance
Sakis are known for their long fur coats and a characteristic thick ring of hair around their head, making it look like they have bangs. Some even call sakis “toupee monkeys” because of this fur crown. Sakis can puff up their fur (a phenomenon called piloerection) when they are startled or threatened, which makes them look much larger than they are. Their tail and torso fur is longer than that on their arms and legs. They have large muzzles and smaller eyes that peer cautiously as they hunch over tree limbs. Their coarse, shaggy fur and hunched posture make them look more like a little bear than a monkey.
Buffy sakis are the most distinct-looking species of the genus. They have cream-blond fur all over their body with orange highlights in some parts. A black strip of fur at their nape expands to cover most of their lower back and continues along their tail, which is covered in black fur. The fur on their chest, belly, and wrists is short, and their hands and feet are off-white. Young sakis are born with dark orange-brown fur, which becomes paler as they age.
Males and females look relatively similar with black facial skin and cream eyebrows, so sexual dimorphism (visual differences between sexes) exists, but it is not immediately obvious. Male faces have small pink patches above their eyes. They also have a smattering of fine white hairs along their lip. Their testicles are light-colored with black speckles. Females have a white stripe under their eyes and along their cheekbones. With age, female buffy sakis exhibit increased white coloration on their faces, occasionally developing a noticeable white fur ring that outlines the face. Both males and females have large throat scent glands with a ring of orange fur, which is larger in males.
Diet
Sakis are considered seed predators, mainly feeding on mature seeds (up to 46% of their diet). They also eat fruits (34% of their diet), leaves, flowers, nectar, and bark; on rare occasions, they consume insects. Seeds are rich in fats and provide more energy than the sugars in fruits. Still, these fats are usually protected by the thick seed coat (mesocarp) that is hard to digest. Sometimes, sakis bite off some part of the seed coat to allow their digestive system to gain access to the fats inside. While studies on saki biology are lacking, some experts think that sakis may have enlarged intestines and long digestion times to extract all the nutrition from seeds. However, research is needed to confirm this hypothesis.
Behavior and Lifestyle
These primates are diurnal (active during the day) and arboreal (tree-dwelling). They are fast-moving and are often called “flying monkeys” in local languages. They use all four limbs (quadrupedal) to run across branches and leap to trees. They are surprisingly agile and noiseless as they move through the thick canopy.
They are generally peaceful and only aggressive when encountering an intruding group competing for space and food. The males in the group lead this territorial behavior. Buffy sakis are typically cautious of humans and avoid them, making observation difficult for researchers.
In many saki species, grooming between family members is a common behavior that helps manage pests like fleas and strengthens the social bonds between individuals (similar to hugs between family members). Though studies on wild buffy sakis are limited, research on closely related species indicates that most grooming happens between mated adults, with females grooming males more. Research on similar saki species suggests that grooming among wild buffy sakis primarily occurs between mated pairs, with females typically grooming males more often. However, studies on this specific species are scarce. Interestingly, males will groom females more when she is pregnant or taking care of their young. As juveniles reach independence, male grooming of females decreases.
Buffy sakis are uniquely covered in long cream-buffy and orange fur on their body.
They have a gular or throat gland, which they rub onto branches to scent and mark their territory.
They are seed predators, mainly eating seeds of mature fruits.
In a family, females usually groom the males, except when she is pregnant or taking care of their young, then the male will groom the female more.
Buffy sakis live in small groups of 3 to 7 individuals, which can be multimale. These groups can break into smaller temporary groups (usually pairs) called parties when food sources are scattered and limited in abundance. They have an extensive home range of 363 to 505 acres (147 to 204 ha) with an estimated density of 9 individuals per 0.6 miles (1 km).
Group dynamics within families are relatively peaceful, though sakis show territorial behavior and aggression toward other saki groups. Females tend to avoid conflict, while males take on the protective role of the family.
As diurnal species, buffy sakis spend early mornings foraging for food and rest during the hottest parts of the day. Not much is known about their daily habits and movements. Buffy sakis live in remote areas that are difficult to traverse, and they are wary of strangers, especially humans, making habituating and studying them a long and challenging process.
Sakis are vocal primates that have a repertoire of whistles, chucks, trills, and purrs. There is insufficient research on what these sounds mean or how sakis respond to them. Adults, especially males, make loud alarm calls when they see potential danger or when they are protecting their territory. Juveniles can be heard making softer “yip” sounds around the adults. Some evidence in related species shows that the length of their calls can differentiate saki species.
Olfactory communication, using their sense of smell, is important in saki ecology. Both males and females have throat or gular glands that exude secretions that they rub onto branches. This behavior marks territory, signals group associations, or even marks important landmarks within their territory. Using these scent marks, a saki family can communicate with intruding sakis, letting them know that this tree is part of their territory and that the intruders should stay away. The scent marks can also let family members know that they are safely within the family’s territory as they travel through the forest. Sakis also use smell to investigate if females are hormonally ready to mate.
Sakis have a flexible mating system. In the wild, they are not strictly monogamous (mating with one individual for long periods). They can engage in polygynandrous mating (where multiple males and females mate). In captivity, they seem to prefer stable monogamous pairs. A saki family usually consists of an adult male-female pair and multiple generations of their offspring.
Buffy sakis do not have a breeding season and can give birth at any time of the year. Females become sexually mature around 3 to 4 years of age and may only give birth for the first time when they reach 6 years old. When a female is hormonally ready to mate, a condition called estrus, she releases hormones through her urine and feces. Male buffy saki monkeys often inspect female genitalia by sniffing near her reproductive organs, primarily to determine if a female is in estrus. If she is, the male will mate with her.
Females are pregnant for about 5 to 6 months (gestation period) and give birth to one infant at a time. Newborns are dark brown and have naked tails. Surprisingly, the infants can still be camouflaged against the paler fur of their mother because her belly is usually in shadow as she walks quadrupedally or sits hunched over. Their dark fur becomes pale, similar to adult females, when they are three weeks old, though the fur remains short. Juvenile males take longer to reach the full size of adult males, with a visibly large throat gland. Many observers would be confused by these juvenile males because they would outwardly look like females (with smaller throat glands and overall smaller size), but they would have male reproductive organs. These juvenile males are often called “transitional males” when they have lingering characteristics of adult females before they develop all the features of an adult male.
Young sakis become more independent around four months old, leaving their mother’s protection to feed themselves for brief periods. By the time juveniles reach 6 months of age, they are entirely independent of their mother, and at eleven months old, they are almost as big as adults.
Seed predators tend to digest and destroy seeds, making them poor seed dispersers compared to animals that feed on only the fruit. As seed predators, sakis do not transport seeds away from the parent plant through their movement or fecal droppings. However, sakis often drop fruits with intact seeds as they forage. One study found that 23% of the seeds they took during foraging sessions were dropped or dispersed close to the foraging site.
Buffy sakis mainly eat seeds, unlike most other primates, who eat fruit and throw away the seeds. Sakis often feed and travel with other primates, such as titi, howler, and woolly monkeys. This association occurs because they consume different parts of trees and thus avoid food competition.
The International Union for Conservation of Nature lists the buffy saki as Least Concern (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Their conservation status was downgraded from “Vulnerable” in 2008 to “Least Concern” in 2015, mainly because their habitat has been affected less by logging and mining than that of other primates in the region. Experts assume buffy saki populations have not changed drastically enough to warrant a more serious conservation status. However, with the current rate of human expansion, it is assumed that the buffy saki population will decline in the future.
Hunting and habitat loss are the main reasons for the declining population of buffy sakis.
These primates live in low densities and are distributed poorly throughout the Amazon forest. Even slight increases in hunting deaths or fewer births due to habitat loss make it hard for this species’ population to recover.
Growing pressure on the Amazon rainforest due to increasing human development and the logging industry leads to deforestation and the loss of crucial fruiting trees. This negatively impacts buffy sakis’ ability to secure sufficient resources for survival. Sakis are hunted for meat; sometimes, their tails are used as dusters or souvenirs. In rare cases, buffy sakis are kept as pets in local communities.
The buffy saki is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
Currently, no specific laws or programs protect buffy sakis. However, some reserves that ban logging and hunting, including the Abufari Biological Reserve and Tefé National Forest, may offer inherent protection to buffy sakis within their boundaries.
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