Silvery Greater Galago (Otolemur monteiri)

Silvery Greater Galago (Otolemur monteiri)

MORPHOLOGY:
The dental formula of this species 2:1:3:3 on both the upper and lower jaw (Ankel-Simons, 2000). The silvery greater galago has a reflecting tapetum, all-rod retina, and an elongated fundus to assist in seeing during the night (Randolph, 1971). This species has a philtrum and a rhinarium (Ankel-Simons, 2000).

This species has two subspecies each having their own distinct pelage colorations:

Otolemur monteiri monteiri: The ventral side of this subspecies is a creamy yellow color while the dorsal side is a light silvery in tone (Groves, 2001). The forehead is brown in this subspecies (Groves, 2001). The hands and feet are dark (Groves, 2001).
Otolemur monteiri argentatus: This subspecies is overall slightly darker than Otolemur monteiri monteiri and the forehead is darker also (Groves, 2001). The tail of this subspecies is often nearly white (Groves, 2001). The hands and feet are dark (Groves, 2001). Groves (2001) reports that there is a high frequency of melanism in this subspecies.

RANGE:
The silvery greater galago is found from Angola in the west, north to Rwanda, and over to western and southeastern Kenya and in northern Tanzania (Groves, 2001). This species lives in the Brachystegia woodland zone (Groves, 2001).

This species has two subspecies each having differing ranges:

Otolemur monteiri monteiri: This subspecies is found from Loanda, Angola in the west to Tabora, Tanzania in the east (Groves, 2001). This subspecies is found in the countries of Angola, Malawi, Mozambique, Tanzania, Zaire, Zambia, and Zimbabwe (Groves, 2001). This subspecies is found east of the Luangwa River in Zambia (Groves, 2001). In Malawi this subspecies occurs as far south as Lusingazi and Deep Bay (Groves, 2001).
Otolemur monteiri argentatus: This subspecies is found from Rwanda to Kenya to Tanzania (Groves, 2001). An all-melanistic population can be found in the Gissenyi District, Rwanda and at Sotik, in Kenya (Groves, 2001).

ECOLOGY:
This is a nocturnal and an arboreal species.

LOCOMOTION:
This species, unlike other galagines, moves quadrupedally through the forest and bush.

SOCIAL BEHAVIOR:
This is a nocturnal species, with both sexes dispersing from the birth territory. Social play that occurs amongst infants consists of wrestling, chases, and hanging upside-down and wrestling (Rosenson, 1972).

VOCAL COMMUNICATION:
raucous cry call: It utters the call from tall trees and the body shakes rapidly while emitting the call (Estes, 1991). These calls can be used by researchers to distinguish individuals from one another (Estes, 1991). This call is uttered most often during the mating season (Estes, 1991).

alarm call: this call can take the form of the following number of noises: rattle, moan, chatter, chirp, whistle-yap, whistle, squawk, creak, knock, and sniff (Estes, 1991). These calls can last for up to an hour (Estes, 1991).

distress call: this call sounds like a yell (Estes, 1991). This is high-pitched and given in response to pain or fear (Estes, 1991). This call not only attracts other silvery greater galagos, but also potential predators (Estes, 1991).

infant click call: like the other galagines, this clicking type call sounds like "tsic" (Estes, 1991). The infant emits this to elicit contact from its mother (Estes, 1991).

sex call: This call, emitted only by the male, is given before and after grooming (Estes, 1991). This call is low frequency and sounds like a crack call (Estes, 1991).

OLFACTORY COMMUNICATION:
chest-gland marking: this is behavior is done by both adult male and female silvery greater galagos (Estes, 1991). The gland on the chest is rubbed against tree trunks and branches (Estes, 1991). This is a highly stereotyped behavior with the silvery greater galago rubbing its chest in hard to reach areas of the trees (Estes, 1991). Its function is marking of a territory, and the dominant males do this most frequently (Estes, 1991).

urine-washing: the silvery greater galago takes its hands and cups them, and then deposits urine on them (Estes, 1991). Next the silvery greater galago takes that urine and spreads it on the soles of the feet (Estes, 1991). When the silvery greater galago walks now, it leaves a little bit of urine on the substrate (Estes, 1991). Males urine-wash more frequently than females do, and when the female is in estrus, the male will deposit the urine directly upon the female, but all age classes perform this behavior (Estes, 1991). A silvery greater galago will urine-wash when foraging in a new area, looking at a strange object, during aggressive encounters, and social grooming (Estes, 1991).

rhythmic urination: the silvery greater galago does this when it is in a new area (Estes, 1991). It moves slowly while depositing a small amount of urine on the substrate (Estes, 1991). This behavior is performed more frequently by female silvery greater galagos than it is by males (Estes, 1991).

VISUAL COMMUNICATION:
defensive attack posture: the silvery greater galago does this when threatened into a corner (Estes, 1991). It stands on its hindfeet with the arms in an outstretched position, with the hands cupped; it tends to look like a boxer (Estes, 1991).

TACTILE COMMUNICATION:
nose-to-nose sniffing: the silvery greater galago does this when first coming upon a conspecific (Estes, 1991). This is followed by nose-to-face contact (Estes, 1991).

nose-to-face contact: this occurs after nose-to-nose sniffing (Estes, 1991). An individual will touch the face of a conspecific with its nose (Estes, 1991).

social grooming: this behavior is not as developed in the silvery greater galago (Estes, 1991). This behavior is basically regulated to reciprocal licking (Estes, 1991).

REPRODUCTION:
The silvery greater galago normally has twins, but triplets and quadruplets have also been observed (Welker and Schafer-Witt, 1988). Infants are carried by the mothers either by the mouth or clinging to the fur of the back, side, belly, or tail (Rosenson, 1972; Welker and Schafer-Witt, 1988).

REFERENCES:
Ankel-Simons, F. 2000. Primate Anatomy. Academic Press: San Diego.

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

Groves, C.P. 2001. Primate Taxonomy. Smithsonian Institute Press: Washington, D.C.

Randolph, M. 1971. Role of light and circadian rhythms in the nocturnal behavior of Galago crassicaudatus. Journal of Comparative and Physiological Psychology. Vol. 74(1), 115-122.

Rosenson, L.M. 1972. Observations of the maternal behaviour of two captive greater bushbabies (Galago crassicaudatus argentatus). Animal Behaviour. Vol. 20, 677-688.

Welker, C. and Schafer-Witt, C. 1988. Preliminary observation on behavioral differences among thick-tailed bushbabies. International Journal of Primatology. Vol. 9(6), 507-518.

Last Updated: October 12, 2003.
[The Primata] [Primate Fact Sheets] [Family Galagonidae] [Otolemur Links]