Diversity
The genus
Pithecia
, more commonly known as Saki monkeys, are New World Monkeys native to neotropical
South America. There are currently 16 described species and can be found throughout
tropical rainforests in the Amazon Basin.
Pithecia
are medium-sized primates that are characterized by their long, thick fur that covers
their whole body. Their tales are non-prehensile and are often at a 1:1 ratio with
their body. The genus prefers mature forests and they spend the majority of their
time foraging in the canopy, and trips to the forest floor are rare. Their conservation
status is unknown as they are very elusive in the wild, but their population is expected
to be in decline due to increasing habitat loss.
Geographic Range
Saki monkeys are distributed across neotropical South America in tropical forests
in the Amazon Basin. They range as far north as the Guiana Shield and as far south
as Northern Bolivia.
- Biogeographic Regions
- neotropical
Habitat
Saki monkeys are arboreal and spend all their time in the canopy. While they can be
found in secondary forests, they are more likely to persist in mature forests with
variable habitat including terra firme, palm swamps, and flooded forest. Their large
geographic distribution is attributed to their ability to persist in a range of forests
types.
Sakis are diurnal and sleep in trees at different designated sleeping spots during
the night. They are very elusive and rarely ever venture to the forest floor.
- Habitat Regions
- tropical
- Terrestrial Biomes
- rainforest
Systematic and Taxonomic History
The genus
Pithecia
consists of about 16 recognized species. The taxonomy of this genus has been widely
difficult to establish due to a lack of genetic information, misuse of common names,
misunderstandings of sexual dimorphism, and imprecise type localities. In a taxonomic
review of the genus in 2019, researchers found evidence for two morphologically diagnosable
groups within genus
Pithecia
(
P. irrorata
and
P. vanzolinii
).The taxonomic uncertainty within the genus
Pithecia
proves that more studies need to be done to evaluate the revise the taxonomic status
of genus.
Physical Description
Saki monkeys are medium sized primates and the smallest of the
Pitheciidae
family. Sakis have a wide range in body length and their tails are often a 1:1 ratio
with their body length. Females are slightly smaller than males in overall size and
weight. Sakis have long, rough hair that covers their entire body, giving them a distinct
shaggy look and oftentimes they appear to have "bangs." Sexual dimorphism varies among
species but males and females generally have distinct pelage markings. Both sexes
have throat glands that are used for scent marking. Sakis do not have prehensile tails
and they can be seen walking, running, climbing, and leaping as their main form of
locomotion.
- Other Physical Features
- endothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
- sexes colored or patterned differently
Reproduction
Species in the genus
Pithecia
live in monogamous social groups. While not much information is known on their reproductive
behaviors in the wild, captive populations have been shown to be more monogamous than
wild populations. Larger groups tend to be polygamous or polyandrous given more than
one primary breeding female and male are present in the group.
- Mating System
- monogamous
- polyandrous
- polygynous
During mating season, male saki monkeys make mating calls to the females in wild populations.
Both males and females become sexually mature at around three years of age, but females
can take longer, given the time their ovarian cycle becomes regular. Females typically
bear only one offspring and the gestation period lasts on average 146 days.
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
Infant saki monkeys will cling to the mother's thigh for the first month of their
life. Then they relocate to the mothers back for the next three months which allows
for better mobility given the size of the growing infant. Once the infant reaches
the age of about five months, it stops clinging from its mother and moves freely within
the group. The offspring still weans from its mother until it can survive on its own.
- Parental Investment
- female parental care
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
- extended period of juvenile learning
Lifespan/Longevity
While not much is known on the longevity of most
Pithecia
species, some species can live up to 36 years in captivity, but the average lifespan
among sakis in the wild is around 15 years.
Behavior
Saki monkeys are social and travel through the canopy in small groups of 2 to 9 individuals.
Their daily activities include moving from sleep trees in early morning to forage
for fruit, then returning to another sleep tree in the evening, often accompanied
by another saki monkey group. Sakis spend anywhere from 9 to 12 hours moving through
the canopy. Allogrooming is practiced extensively throughout the day and is most commonly
seen between mothers and infants. Saki monkeys have a variety of specialized vocalizations
including trills, whistles, grunts, roars, and squeaks, which are used for various
intensity dependent aggressions.
- Key Behaviors
- arboreal
- scansorial
- saltatorial
- diurnal
- motile
- sedentary
- territorial
- social
Communication and Perception
Sakis communicate to each other and to other groups by loud vocalizations, and often
establish their territories when male and female pairs, typically the breeding individuals,
make loud calls. Sakis have scent glands on their chests/throats and adult males mark
their territory using a combination of urine and scent gland markers.
- Other Communication Modes
- duets
- pheromones
- scent marks
- vibrations
- Perception Channels
- visual
- tactile
- acoustic
- vibrations
- chemical
Food Habits
Species in the genus
Pithecia
are specialized for eating the seeds of fruiting bodies. Apart from seeds they consume
fruits, flowers, leaves, and nuts. Leaves are eaten more often in the dry season when
fruit is not available. Since their diet lacks protein, they have been known to eat
insects to make up for their high fat intake.
Predation
Saki monkeys make alarm calls when a predator is near the group. Once the first alarm
call is made, the rest of the group joins. The group stays motionless after making
the call so they are undetectable within the canopy, then they move away from the
threat. Sakis have both terrestrial predators like jaguars and anacondas, as well
as avian predators like the harpy eagle.
- Anti-predator Adaptations
- aposematic
- cryptic
Ecosystem Roles
Sakis play a major role in seed dispersal. Some species of sakis, including
Pithecia pithecia
, have been recorded for having parasites like roundworm, heartworm, and the Mayaro
virus.
- Ecosystem Impact
- disperses seeds
Economic Importance for Humans: Positive
Sakis are commonly hunted and captured for their meat in the Amazon basin. They are
also trapped for the pet trade, although they don't live long when kept as a pet because
their diet requirements are hard to meet. While there are only a handful of Pithecia
species in captivity, they attract many visitors in zoos. Sakis that have been habituated
near hotels and ecolodges in the Amazon are also big tourist attractions.
Economic Importance for Humans: Negative
The adverse effects saki monkeys have on humans is unknown. Studies have shown that
sakis can carry diseases that can be transmitted to humans, including the human herpesvirus
(HHVI) and hepatitis.
- Negative Impacts
-
injures humans
- carries human disease
- causes or carries domestic animal disease
Conservation Status
The conservation status of most saki monkeys are of least concern, but there is a
data deficiency for almost all saki species, including
Pithecia irrorata
,
Pithecia milleri
, and
Pithecia rylandsi
, and current populations are unknown. However, increasing habitat loss and fragmentation
due to deforestation and gold mining in the Amazon is assumed to be causing a rapid
decline in their populations.
Additional Links
Contributors
Sierra Larson (author), Colorado State University, Audrey Bowman (editor), Colorado State University.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- monogamous
-
Having one mate at a time.
- polyandrous
-
Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).
- polygynous
-
having more than one female as a mate at one time
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- saltatorial
-
specialized for leaping or bounding locomotion; jumps or hops.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- territorial
-
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
- social
-
associates with others of its species; forms social groups.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- duets
-
to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- scent marks
-
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- chemical
-
uses smells or other chemicals to communicate
- aposematic
-
having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- food
-
A substance that provides both nutrients and energy to a living thing.
- causes or carries domestic animal disease
-
either directly causes, or indirectly transmits, a disease to a domestic animal
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
- frugivore
-
an animal that mainly eats fruit
- granivore
-
an animal that mainly eats seeds
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
References
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