Angolan Black-and-white Colobus Monkey (Colobus angolensis)



MORPHOLOGY:
The adult body mass for this species ranges from 6.0 to 11.4 kilograms. The pelage of this species is black with white on the sides of the face, on the throat, and on the tip of the tail. The infants are born all white and start turning color at about 3 months. This species has a sacculated stomach to assist in the breakdown of cellulose.

RANGE:
The Angolan black-and-white colobus monkey is found in the countries of Angola, Burundi, Kenya, Rwanda, Tanzania, Uganda, Zaire, and Zambia. This species is found in a variety of habitat types including: gallery, montane, lowland, and alpine bamboo forests, savannas, and swamp lands.

ECOLOGY:
The Angolan black-and-white colobus monkey is primarily a folivorous species, but it also consumes termite clay, fruits, and flowers. Group sizes range from about 10 to 15 individuals. This is a diurnal species. This is an arboreal species. This species obtains much of its water from the food it eats.

LOCOMOTION:
The Angolan black-and-white colobus monkey moves through the forest quadrupedally (Fleagle, 1988). This species also is capable of leaping where it uses this in communication and to avoid predators (Estes, 1991). This species climbs downward head first and climbing up it uses its hindlegs to propel it up the trunk (Estes, 1991).

SOCIAL BEHAVIOR:
The basic social structure of Angolan black-and-white colobus monkey is a group of related females with their offspring and a territorial male (Estes, 1991). Troops do accept other males, but multimale troops are rare (Estes, 1991). The males of this species disperse (Estes, 1991). This is a highly territorial species. Infants of the group, especially when they are still white are handled not only by the mother but by adult and subadult females and sometimes by subadult males (Estes, 1991).

VOCAL COMMUNICATION:
roaring: This call is low, resonant, and resembles a croaking sound accompanied by a rolling "rurr, rurr, rurr" noise (Estes, 1991). This call is emitted by territorial males (Estes, 1991). This functions as a territorial call and may be used as a threat call (Estes, 1991). Jumping about occurs with this call occasionally (Estes, 1991).

snorting: This call is emitted by all except infants and males do this sometimes before roaring (Estes, 1991). This call is explosive in nature and is used as an alarm call (Estes, 1991).

snuffling: This call resembles a pig rooting and is emitted by females and young (Estes, 1991). This call occurs during conflicts and is used to communicate mild distress (Estes, 1991).

squealing: This call is emitted by females and young individuals and is used to communicate strong distress (Estes, 1991). This call is graded and varies (Estes, 1991). An example of this is when an infant is pushed away from its mother, the mother will respond by picking it up (Estes, 1991).

purring: This call is emitted before troop movements and may be used to coordinate them, and also maybe to alert that predators are nearby (Estes, 1991).

tongue-clicking: This is done before aggressive interactions and adults of both sexes do this (Estes, 1991).

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:
open mouth (low-intensity): This is where the mouth is half-opened for a short time ( < 1 second ) (Estes, 1991). This is performed by all except infants (Estes, 1991). This is seen in situations of general arousal and low-level aggression (Estes, 1991).

open mouth (high-intensity): This is where the mouth is fully open and the tongue is clicking (Estes, 1991). This is performed by adult males and females and subadult males (Estes, 1991). This serves to communicate aggression and occurs mostly between males in intertroop encounters (Estes, 1991).

gape: This is where the mouth is open for at least 1 second, the teeth are covered and stare may occur with it (Estes, 1991). This is performed by adult males (Estes, 1991). This is a threat display and occurs when a group member comes too close (Estes, 1991).

yawn: This is where the mouth is open to expose the teeth, and is done in a series of 2 to 3 yawns (Estes, 1991). This display is performed by adult males and females (Estes, 1991). This is used as a threat display between males during intertroop encounters and also used as a sign of tension (Estes, 1991).

stare: This is where the head is up and the individual is gazing at the intended receiver. This display may occur with forward threat and is performed by adult males (Estes, 1991). This is either a threat signal or of territorial vigilance directed towards another troop (Estes, 1991).

forward threat: This is when an individual crouches on its hands and feet with the head extended and occurs with stare (Estes, 1991). This display is performed by adult males and is used as a threat display (Estes, 1991).

stiff-legs display: This is where the individual is sitting with the legs pointed downward with knees slightly flexed and the feet unsupported and is held for 1 to 30 seconds (Estes, 1991). This is performed by all members except infants and is used as a threat display (Estes, 1991).

penile display: This is done by adult and subadult males and is a partial erection of the penis and is combined with stiff-legs display (Estes, 1991). This is used to threaten other troops and to advertise territoriality (Estes, 1991).

arm-raise: This is when one individual raises or pushes their arm towards another conspecific (Estes, 1991). This is performed by adults and is used to communicate a threat with the intent to increase distance (Estes, 1991).

jumping about: This is where an individual will make big jumps through the tree canopy with an exaggerated, noisy landing, and often occurs with roaring (Estes, 1991). This display is performed by adult males and is used to advertise territoriality and as a threat against rival males and predators (Estes, 1991).

branch-shaking: This is where an individual is shaking branches with the hindlegs and the hands are holding on to another branch (Estes, 1991). This performed by adult and subadult males and young during play and is used as a threat display (Estes, 1991).

supplanting: This is when one troop member approaches another troop member with the intent to be in his position and is done by adult males (Estes, 1991). This is used to obtain a good feeding position (Estes, 1991)>

grimace: This is where the mouth is wide open with the lips retracted showing the teeth and the face is puckered (Estes, 1991). This is done by females and young and is used to communicate submission (Estes, 1991).

chasing: This is done by adult males and occurs during aggression between troops (Estes, 1991).

displacement scratching: This is self-grooming done with the hands and feet and is performed by all except new infants (Estes, 1991). This communicates slight tension and often occurs when individuals are waiting for the leader to begin troop movement (Estes, 1991).

social presenting: This is where the sender positions their body so the hindquarters are facing the receiver and the body is more lower than in presenting (Estes, 1991). This is performed by females, subadult males, and juveniles and is used to communicate submission to a more dominant individual and gets a response of social mounting or social grooming (Estes, 1991).

TACTILE COMMUNICATION:
social mounting: The performer of this stands and resembles a sexual mount and is done by all except small infants (Estes, 1991). This often occurs before social grooming and is a response to social presenting (Estes, 1991).

embrace: The performer is seated and occur from the front or from behind and is done by females and young (Estes, 1991). This comes before social grooming and also serves as a greeting behavior (Estes, 1991).

touch (with hand): This done by all and is used to solicit social grooming and occasionally copulation, and it communicates a friendly intent (Estes, 1991).

social grooming: This is when one individual grooms another and is used to reinforce the bonds between individuals. In this species it occurs more frequently in the presence of another troop (Estes, 1991). Parasites and dead skin is removed with lips and/or tongue (Estes, 1991).

REPRODUCTION:
The Angolan black-and-white colobus monkey gives birth to a single offspring.

presenting: This behavior is preformed by the female to elicit copulation from the male; this pattern tells the male that she is ready for copulation (Estes, 1991).

REFERENCES:
Burton, Frances. 1995. The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

Estes, R.D. 1991. The Behavior Guide to African Mammals. University of California Press.

Fleagle, John G. 1988. Primate Adaptation and Evolution. Academic Press.

Last Updated: October 7, 2003.
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