Panamanian Night Monkey
Encyclopedia
The Panamanian night monkey or Chocoan night monkey (Aotus zonalis) is a species of night monkey
formerly considered a subspecies of the gray-bellied night monkey
of the family Aotidae. Its range consists of Panama
and the Chocó region of Colombia
. There are also unconfirmed reports of its occurrence in Costa Rica
, especially on the Caribbean
coast of Costa Rica
. The species definitely occurs in the Atlantic
lowlands of Panama close to the Costa Rica border.
The exact classification of the Panamanian Night Monkey is uncertain. While some authors consider it a subspecies of the gray-bellied night monkey, A. lemurinus, other authors follow a study by Thomas Defler
from 2001, which concluded that it is a separate species, A. zonalis.
The Panamanian night monkey is a relatively small monkey, with males weighing approximately 889 grams (31.4 oz) and females weighing about 916 grams (32.3 oz). The fur on the back ranges from gray-brown to reddish-brown. The belly is yellow. The hair on the back of the hands and feet is black or dark brown, which is a key distinguishing feature from other northern "gray-necked" Aotus species; also, its hair is shorter. Other distinguishing features relate to its skull
, which has a broad braincase, a depressed interorbital region
, and large molariform
teeth.
Like other night monkey
s, the Panamanian night monkey has large eyes, befitting its nocturnal lifestyle. But unlike many nocturnal animal species, its eyes do not have a tapetum lucidum
. Also like other night monkeys, it has a short tail relative to the body size.
The Panamanian night monkey is arboreal and nocturnal. It and the other members of the genus Aotus are the only nocturnal monkeys. It is found in several types of forest, including secondary forest
and coffee
plantations. It lives in small groups of between two and six monkeys, consisting of an adult pair and one infant and several juveniles and/or subadults. Groups are territorial, and groups occupy ranges that overlap only slightly.
Vocal, olfactory and behavioral forms of communication have all been recorded. At least nine vocal calls have been reported, including various types of grunts, screams, squeals, moans and trills. Males develop a scent gland near their tail at about one year old that is used for scent marking. Urine washing, in which urine
is rubbed on the hands and feet, is also used. Behavioral communication appears to be less important than vocal and olfactory communication, but certain behavioral displays, including arched back displays, stiff legged jumping, urination, defecation
and piloerection have been noted.
The Panamanian night monkey generally walks on all four legs, although it is capable of leaping or running when necessary. It eats a variety of foods. In one study, on Barro Colorado Island
in Panama, its diet was found to consist of 65% fruits, 30% leaves and 5% insects.
In common with other night monkeys, the Panamanian night monkey is one of the few monogamous monkeys. The monogamous pair generally gives birth to a single infant each year, although twins occasionally occur. The gestation
period is about 133 days. The father carries the infant from the time it is one or two days old, passing it to the mother for nursing
.
Although viewing monkeys is popular with tourists visiting Panama, the Panamanian night monkey's nocturnal habits make it less often seen than the other Panamanian monkey species. However, with a skilled guide it is possible to observe the Panamanian night monkey.
Night monkey
The night monkeys, also known as the owl monkeys or douroucoulis, are the members of the genus Aotus of New World monkeys . They are widely distributed in the forests of Central and South America, from Panama south to Paraguay and northern Argentina...
formerly considered a subspecies of the gray-bellied night monkey
Gray-bellied Night Monkey
The gray-bellied night monkey , also called the lemurine owl monkey, is a small New World monkey of the family Aotidae...
of the family Aotidae. Its range consists of Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
and the Chocó region of Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. There are also unconfirmed reports of its occurrence in Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
, especially on the Caribbean
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
coast of Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
. The species definitely occurs in the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
lowlands of Panama close to the Costa Rica border.
The exact classification of the Panamanian Night Monkey is uncertain. While some authors consider it a subspecies of the gray-bellied night monkey, A. lemurinus, other authors follow a study by Thomas Defler
Thomas Defler
Thomas R. Defler is a North American primatologist who has lived and worked in Colombia for many years. He earned his PhD from the University of Colorado at Denver in 1976 and then he moved to Colombia...
from 2001, which concluded that it is a separate species, A. zonalis.
The Panamanian night monkey is a relatively small monkey, with males weighing approximately 889 grams (31.4 oz) and females weighing about 916 grams (32.3 oz). The fur on the back ranges from gray-brown to reddish-brown. The belly is yellow. The hair on the back of the hands and feet is black or dark brown, which is a key distinguishing feature from other northern "gray-necked" Aotus species; also, its hair is shorter. Other distinguishing features relate to its skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
, which has a broad braincase, a depressed interorbital region
Interorbital region
The interorbital region of the skull is located between the eyes, anterior to the braincase. The form of the interorbital region may exhibit significant variation between taxonomic groups....
, and large molariform
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
teeth.
Like other night monkey
Night monkey
The night monkeys, also known as the owl monkeys or douroucoulis, are the members of the genus Aotus of New World monkeys . They are widely distributed in the forests of Central and South America, from Panama south to Paraguay and northern Argentina...
s, the Panamanian night monkey has large eyes, befitting its nocturnal lifestyle. But unlike many nocturnal animal species, its eyes do not have a tapetum lucidum
Tapetum lucidum
The tapetum lucidum is a layer of tissue in the eye of many vertebrate animals....
. Also like other night monkeys, it has a short tail relative to the body size.
The Panamanian night monkey is arboreal and nocturnal. It and the other members of the genus Aotus are the only nocturnal monkeys. It is found in several types of forest, including secondary forest
Secondary forest
A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...
and coffee
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...
plantations. It lives in small groups of between two and six monkeys, consisting of an adult pair and one infant and several juveniles and/or subadults. Groups are territorial, and groups occupy ranges that overlap only slightly.
Vocal, olfactory and behavioral forms of communication have all been recorded. At least nine vocal calls have been reported, including various types of grunts, screams, squeals, moans and trills. Males develop a scent gland near their tail at about one year old that is used for scent marking. Urine washing, in which urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
is rubbed on the hands and feet, is also used. Behavioral communication appears to be less important than vocal and olfactory communication, but certain behavioral displays, including arched back displays, stiff legged jumping, urination, defecation
Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...
and piloerection have been noted.
The Panamanian night monkey generally walks on all four legs, although it is capable of leaping or running when necessary. It eats a variety of foods. In one study, on Barro Colorado Island
Barro Colorado Island
Barro Colorado Island is located in the man-made Gatun Lake in the middle of the Panama Canal. The island was formed when the waters of the Chagres River were dammed to form the lake. When the waters rose, they covered a significant part of the existing rainforest, and the hilltops remained as...
in Panama, its diet was found to consist of 65% fruits, 30% leaves and 5% insects.
In common with other night monkeys, the Panamanian night monkey is one of the few monogamous monkeys. The monogamous pair generally gives birth to a single infant each year, although twins occasionally occur. The gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
period is about 133 days. The father carries the infant from the time it is one or two days old, passing it to the mother for nursing
Lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...
.
Although viewing monkeys is popular with tourists visiting Panama, the Panamanian night monkey's nocturnal habits make it less often seen than the other Panamanian monkey species. However, with a skilled guide it is possible to observe the Panamanian night monkey.