Galago thomasiThomas's bushbaby

Geographic Range

The range of Thomas’s bushbabies extends from Cote d'Ivoire through Cameroon, Angola, and Congo-Zaire to Uganda, Tanzania, and Zambia, and possibly northern Kenya around Mount Marsabit. They may occur in several other African countries but due to recent taxonomic changes this has yet to be clarified. ("The IUCN Red List of Threatened Species", 2008; Groves, 2001; Perkin and Bearder, 2004)


Thomas’s bushbabies are found in a variety of different habitats, including primary and secondary forests, marshy areas, gallery forest, savanna, and open woodlands such as miombo. They inhabit both lowland forests and highland forest and wooded areas up to 2000 meters. ("The IUCN Red List of Threatened Species", 2008; Rowe, 1996)

  • Range elevation
    2000 (high) m
    6561.68 (high) ft

Physical Description

Thomas’s bushbabies are brownish-grey with grey underparts, prominent dark eye patches, narrow faces, and dark rostra. Thomas’s bushbabies resemble Prince Demidoff’s bushbabies (Galago demidoff). Although not typically visible in the field, a distinguishing feature is the genital morphology of Thomas’s bushbabies, which differs from all other members of the Galagidae family. The body length of Galago thomasi averages 146 mm, with a range of 123 to 166 mm, tail length averages 261 mm, ranging from 150 to 233 mm. Thomas’s bushbabies weigh, on average, 99 g, but varies in weight from 55 to 149 g. Males are larger than females. (Rowe, 1996)

  • Sexual Dimorphism
  • male larger
  • Range mass
    55 to 149 g
    1.94 to 5.25 oz
  • Average mass
    99 g
    3.49 oz
  • Range length
    123 to 166 mm
    4.84 to 6.54 in
  • Average length
    146 mm
    5.75 in


Studies of the reproductive behavior of Galago thomasi are lacking. In other members of the family Galagidae for which data are available, the mating systems consist of polygynous multi-male groups. Male galagos have a baculum, and there are typically species-specific differences in penile morphology among the Galagidae. (Macdonald, 2001)

Although data are lacking for G. thomasi, other galagos, such as Galago demidoff, breed year-round. Typically they reproduce between January and April. Information on the gestation period and the number of offspring born are not available for Galago thomasi, however, in Galago demidoff females have a gestation period of 111 to 114 days and one young at a time. Offspring in G. demidoff are weaned at around 53 days of age and reach sexual maturity at an age of 8 to 10 months. (Llorente, et al., 2003; Rowe, 1996)

  • Breeding interval
    Thomas's bushbabies breed year round.
  • Breeding season
    Although Thomas's bushbabies breed year round, most births occur from January through April.
  • Range number of offspring
    1 to 2
  • Average number of offspring

There is no information currently on parental investment in G. thomasi and whether or not there are male and female contributions to the care of offspring. In other Galago species females primarily care for the young and generally hide them in a protected spot while they forage. Males may provide some indirect care for young through protecting foraging areas and there is some evidence that males may associate with females and their young on occasion.

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


The lifespan of Galago thomasi is not reported in the literature. The closely related Galago demidoff has been known to live 13 years in the captivity. (Rowe, 1996)


Thomas’s bushbabies are both nocturnal and arboreal. They spend much of their waking time foraging solitarily. They inhabit higher levels of the forest, usually above 20 meters. After foraging for the night individuals usually come together in the early morning hours before dawn. They have been found sleeping together as well. Group dynamics are considered complex, but groups are highly dispersed during foraging periods. They have been observed allogrooming when meeting one another and they make many postural motions with their bodies. Compared to Galago matschei, G. thomasi uses arboreal quadrupedalism more, although both species make much use of leaping. Thomas’s bushbabies primarily use small, oblique, mid-canopy branches. In Kibale Forest, Uganda, Thomas’s bushbabies were reported nesting in the night nest of a common chimpanzee Pan troglodytes, despite the fact that chimpanzees regularly prey upon galagos. (Macdonald, 2001; Off and Gebo, 2005)

  • Range territory size
    .006 to .014 km^2

Home Range

Home range size in Thomas’s bushbabies is not known. In another species, Galago demidoff, the home range was found to be 0.6 to 1.4 ha. (Rowe, 1996)

Communication and Perception

The facial markings of the different species in the family Galagidae may help them distinguish one individual from another when they come into contact. Galago thomasi individuals use chemical cues extensively. They have a scent gland near the anal region that is used in scent marking to communicate with conspecifics. They also urinate on their cupped hands, then spread the urine on their feet, so it is spread when they walk. This behavior, urine-washing, is more frequent in males than females, and is carried out in a variety of situations. Thomas’s bushbabies also have species-specific calls: they have a rolling call that rises to a crescendo and is then repeated several times. These calls can be used to communicate position to one another as well as to indicate mood. Tactile communication takes the form of nose-to-nose sniffing then nose-to-face contact when conspecifics first encounter each other. They also reciprocally lick each other, depositing saliva and sometimes urine. ("Thomas's Galago (Galago thomasi)", 2007; Macdonald, 2001)

Food Habits

Like other galagos, Thomas’s bushbabies eat a variety of foods, but are primarily insectivorous. They consume small vertebrates and insects, fruit, tree buds and leaves, as well as tree gums. They use their large ears to listen for insects and small vertebrates and have been known to catch insects in mid-air. ("Thomas's Galago (Galago thomasi)", 2007; Macdonald, 2001; Rowe, 1996)

  • Animal Foods
  • reptiles
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • seeds, grains, and nuts
  • fruit
  • sap or other plant fluids


Because of their small size, Thomas’s bushbabies are likely to be preyed on by nocturnal predators such as small carnivores and owls. During the daytime, even though they sleep in small tree hollows or crevices, galagos are not always safe from predators. Common chimpanzees Pan troglodytes have been observed using a stick as a spear in order to reach a sleeping Galago demidoff in its nest and it seems likely they would prey upon G. thomasi as well. Arboreal snakes may also be a threat. ("Predation on Mammals by the Chimpanzee", 1997; Macdonald, 2001)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Thomas’s bushbabies help to disperse seeds of the fruits that they eat. They also presumably serve as prey for smaller forest carnivores and regulate arthropod communities through their predation. Trypanosomes have been found in the blood of Thomas’s bushbabies in Kivu Province, Democratic Republic of Congo. ("Predation on Mammals by the Chimpanzee", 1997; Van Den Berghe and Peel, 2007)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species
  • trypanosomes (Trypanosomatida)

Economic Importance for Humans: Positive

Thomas’s bushbabies do not play any major economic roles for humans. They may provoke some interest by ecotourists, but they are active at night and rarely observed.

Economic Importance for Humans: Negative

There are no known negative impacts of Thomas’s bushbabies on humans.

Conservation Status

The IUCN lists Galago thomasi as lower risk/least concern. This status is due to their adaptability to different types of environments rather than reliance on primary and secondary rainforests that are being destroyed by humans in Africa for agriculture. With education both for the local people where the animals live and educating the general public on the importance of natural ecosystems Galago thomasi may be able to stay listed as lower risk least concern. ("The IUCN Red List of Threatened Species", 2008)


Tanya Dewey (editor), Animal Diversity Web.

Jeremy Phan (author), Michigan State University, Pamela Rasmussen (editor, instructor), Michigan State University.



living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map


uses sound to communicate


Referring to an animal that lives in trees; tree-climbing.

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.


an animal that mainly eats meat


uses smells or other chemicals to communicate


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.


humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.


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.


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


An animal that eats mainly insects or spiders.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


marshes are wetland areas often dominated by grasses and reeds.


having the capacity to move from one place to another.


This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


an animal that mainly eats all kinds of things, including plants and animals


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.


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.


Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).


specialized for leaping or bounding locomotion; jumps or hops.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


lives alone


a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.


uses touch to communicate


Living on the ground.


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


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year


1997. Predation on Mammals by the Chimpanzee. Primates, 38(2): 193-214. Accessed September 04, 2008 at

2008. "The IUCN Red List of Threatened Species" (On-line). Galagoides thomasi. Accessed February 01, 2009 at

2007. "Thomas's Galago (Galago thomasi)" (On-line). Accessed February 01, 2009 at

Groves, C. 2001. Primate Taxonomy. United States of America: Smithsonian Institution.

Llorente, M., J. Pi, A. Houle. 2003. Association between Galago thomasi and Pan troglodytes schweinfurthii in the Kibale National Park, Uganda. Folia Primatologica, 74(2): 80-84. Accessed February 01, 2009 at

Macdonald, D. 2001. The Encyclopedia of Mammals. London: The Brown Reference Group.

Off, E., D. Gebo. 2005. Galago locomotion in Kibale National Park, Uganda. American Journal of Primatology, 66(2): 189-195. Accessed February 01, 2009 at

Perkin, A., S. Bearder. 2004. "Minziro Forest reveals new galago and bat records for Tanzania" (On-line). The Arc Journal. Accessed February 01, 2009 at

Rowe, N. 1996. The Pictorial Guide to Living Primates. Hong Kong: Pogonias Press.

Van Den Berghe, L., M. Peel. 2007. Trypanosomes of the African lemurs, Perodicticus potto ibeanus and Galago demidovi thomasi. Journal of Eukaryotic Microbiology, 10(2): 133-135. Accessed February 01, 2009 at