Animal Diversity Web

Diversity

Species in the genus Galago, commonly called lesser galagos or lesser bushbabies, are small, arboreal primates. The genus currently comprises four extant species: Somali galagos (Galago gallarum), dusky galagos (Galago matschiei), Moholi galagos (Galago moholi), and Senegal galagos (Galago senegalensis). All four species are also known by other common names. For example, Senegal galagos are also called Senegal bushbabies or northern lesser galagos. The number of species that belong in the genus Galago is disputed and still under revision. The genus previously included 14 galago species, but 10 of these species have been reclassified to other genera based on genetic evidence.

Lesser galagos are likely the most numerous primates in Africa, as species can be found in a variety of environments across the continent. They inhabit forests, savannas, bushlands, and open woodlands. Lesser galagos are nocturnal, with large eyes and ears that help them navigate in the dark. Species in the genus Galago typically use vocalizations to communicate with conspecifics. Lesser galagos are primarily gummivores, eating gum and sap from trees, but they eat a variety of other plant material and insects. ("Animals of the Masai Mara", 2013; Groves, 2021; "Lesser Galagos (Genus Galago)", 2022)

Geographic Range

Lesser galagos inhabit areas throughout Sub-Saharan Africa. The exact geographic distribution of lesser galagos varies between species. (Gron, 2008)

• Biogeographic Regions
• ethiopian
  • native

Habitat

Lesser galagos are found throughout East Africa and Sub-Saharan Africa, typically in forest or scrubland environments. Most species are primarily arboreal, inhabiting woodlands and scrublands that are often dominated by acacia plants (genus Acacia). However, some species are more commonly found on the ground.

During the day, lesser galagos nest in protected areas such as tree hollows or old bird nests. At night, they forage in trees or occasionally on the ground. Lesser galagos are typically found at elevations less than 2,000 m above sea level. ("Animals of the Masai Mara", 2013; Foley, et al., 2014; "Lesser Bush Baby", 2022; Nowack, et al., 2012)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest
• scrub forest

Systematic and Taxonomic History

Species in the genus Galago are part of the family Galagidae, which includes all galagos and bushbabies. Compared to other primate families, Galagidae is still poorly understood due to a lack of molecular data and ancestral fossil evidence. Galagos were previously considered to be a subfamily within the family Lorisidae, which includes lorises and pottos, but they have since been distinguished into their own family. There were originally only two genera in the family Galagidae: needle-clawed galagos (genus Euoticus) and lesser galagos (genus Galago). However, four more genera have since been defined. The newly defined genera include greater galagos (genus Otolemur), western dwarf galagos (genus Galagoides), eastern dwarf galagos (genus Paragalago) and squirrel galagos (genus Sciurocheirus). Many of the species that were previously considered a part of the genus Galago have since been reclassified into other genera in the family Galagidae.

Up to 14 species have been previously described within the genus Galago, but this number is heavily disputed and constantly revised, mainly because species are difficult to differentiate. Researchers rely on vocalizations, genetics, and sometimes morphology to distinguish species. There are currently four confirmed species: Somali galagos (Galago gallarum), dusky galagos (Galago matschiei), Mohol galagos (Galago moholi), and Senegal galagos (Galago senegalensis). Mohol galagos were once considered a subspecies of Senegal galagos, but are now defined as separate species. (Foley, et al., 2014; Groves, 2021; Pozzi, et al., 2014; Williams, 2015)

Physical Description

Lesser galagos are small primates, measuring 30 to 40 cm in length, and 95 to 300 g in body mass, depending on the species. They have short, wooly pelage that ranges in color from gray to light brown. Lesser galagos have long tails that range in color from light brown to black, with shorter hair at the base and longer hair near the tip. Lesser galagos have characteristically large ears and a stripe of white coloration along the dorsal side of their snouts. They have have tooth combs on their bottom jaws and a grooming claw, which is characteristic of species in the suborder Strepsirrhini. Lesser galagos have long, slender fingers with pads at the tips to improve grip. Unlike other primates (order Primates), lesser galagos cannot move their digits independently of each other. They have large, round eyes with a large number of rod cells, which gives them exceptional low light vision. However, they have dichromatic vision meaning they are red-green color blind. Lesser galagos can leap large distances using their long hind legs, and can often be found sitting upright and clinging to vertical branches. Many species are indistinguishable from each other morphologically, and must be differentiated by vocalization characteristics or genetic markers. ("Animals of the Masai Mara", 2013; Barnes, 2016; Foley, et al., 2014)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Lesser galagos tend to be polygynous, but polyandrous and polygynandrous behaviors have been observed in some species. When females are not in estrus, the skin around their vaginas swells to prevent copulation. Females only enter estrus for 1 to 4 days at a time, during which time females may mate with one or several males. When females are in estrus, the testes of males increase in size. Testis size may play a role in female mate choice, and it is likely that sperm competition is an important factor in male fitness. Thus the number of sperm produced likely enhances reproductive success. In the wild, all mating events are initiated by persistent males, and females tend to be averse to mating attempts. However, captive females have been observed to display their hindquarters while they are in estrus, presumably as an attempt to initiate copulation. (Doyle and R.D. Martin, 1979; Gron, 2008; Scheun, et al., 2016)

• Mating System
• polyandrous
• polygynous
• polygynandrous (promiscuous)

Several lesser galago species have two mating periods and two birth periods per year. For other species, information on reproductive cycles is limited but likely to be similar. Lesser galagos typically breed once at the onset of the rainy season in November, and again at the end of the rainy season in February. Male body mass and testis volume increases immediately prior to breeding periods. The ovarian cycle of females is 31 to 38 days in duration, depending on the species.

Females gestate fertilized eggs for 111 to 142 days, with smaller species having shorter average gestation periods. Lesser galagos give birth to 1 to 3 offspring at a time, with twins being fairly common and triplets being extremely rare. Some species, like Mohol galagos (Galago moholi), are more likely to have twins compared to other species. Newborn lesser galagos range in body mass from 5 to 24 g, depending on maximum adult size. They are born with open eyes and thin, grey pelage. Juveniles develop thicker fur by the time they are 2 to 3 weeks old. They typically reach sexual maturity between 8 and 18 months old, depending on the species. (Barnes, 2016; Doyle and R.D. Martin, 1979; Scheun, et al., 2016)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

Lesser galago females exhibit extended parental care, whereas males exhibit little parental investment beyond the act of mating. Female lesser galagos typically live in social groups, but they often isolate themselves as they reach the end of a pregnancy. They typically give birth in protected areas, such as abandoned bird nests or tree hollows. Following parturition, females return to their social group to rear their young. Mothers are often observed carrying infants in their mouths, typically by the nape of their necks. In some species, young juveniles have also been recorded clinging to their mother.

Soon after birth, juveniles are able to cling to branches and walk on all fours. By the time they are two weeks old, juveniles can run and climb comfortably. Although they can move independently from their mothers by around 4 to 6 weeks old, they are not fully weaned until they are 10 to 14 weeks old. Time to independence varies between lesser galago species. In several species, females have been observed nursing infants that are not their own. Adult females within maternity groups also participate in allogrooming behaviors and playful behaviors with juveniles. When juvenile males reach puberty, often at around 10 months of age, they leave the female social groups in which they are raised. (Doyle and R.D. Martin, 1979; "Lesser Bush Baby", 2022; Scheun, et al., 2016)

• Parental Investment
• precocial
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Lesser galagos have a maximum recorded lifespan 16.5 years in captivity. It is suspected they can live 14 to 16 years in the wild, but further research is needed to confirm this. Like many other primates, senescence limits their longevity. Due to their small size, lesser galagos tend to senesce at a faster rate compared to larger primates. (Austad, 1997)

Behavior

Lesser galagos are primarily arboreal, although they occasionally forage on the ground. They move through low forest trees by walking on all fours or leaping with their long, powerful hind feet. Lesser galagos have long digits and finger pads, which help them grasp branches while navigating in branches.

Lesser galagos are crepuscular and nocturnal. They are most active just after dusk and before dawn, but they are also active at night. Females are usually territorial, spreading out evenly across suitable environments. Males are often active near female territories, though this is not always the case. Lesser galagos urinate on their hands and feet, most likely to mark their territory and potentially to help them grip tree branches. Although lesser galagos tend to forage alone, females have been observed to forage in small social groups with as many as six individuals. Females also rest in communal nests with other females. The social systems of lesser galagos have been poorly studied, so detailed information on social hierarchies is unavailable.

Lesser galagos enter brief periods of torpor in cold temperatures, but they have several behavioral adaptations that they use more regularly to avoid inclement conditions. For example, they often select insulated resting sites and huddle together in small groups to stay warm. In general, lesser galagos sleep in areas with high levels of canopy cover and connectivity between canopy vegetation. They also select areas with more mid-level vegetative cover, higher tree density, and higher numbers of Acacia trees (genus Acacia). ("Animals of the Masai Mara", 2013; Ellison, et al., 2019; Foley, et al., 2014; Nowack, et al., 2012)

• Key Behaviors
• arboreal
• nocturnal
• motile
• territorial
• social

Communication and Perception

Lesser galagos primarily use vocalizations to communicate with conspecifics. They produce loud cries, reminiscent of human babies, hence the alternative common name “lesser bushbabies”. Lesser galago vocalizations vary in pitch and duration between species. For example, Mohol bushbabies (Galago moholi) produce long, complex, high-pitched calls that increase in intensity, and Senegal bushbabies (Galago senegalensis) produce single-note, low-pitched calls at a regular tempo. Lesser galagos use vocalizations to communicate in a number of different contexts, such as when they are threatened by predators or acting aggressively towards other lesser galagos. They also comunicate with conspecifics with chemical stimuli, using their urine to mark their territories.

Lesser galagos primarily use visual, olfactory, and auditory information to perceive their environment. Their eyes cannot move much within their eye sockets, so lesser galagos compensate by moving their heads. Because lesser galagos are nocturnal, their eyes are adapted to work well in low-light conditions. Their retinas have a large number of rod cells and few cone cells. Lesser galagos also have large ears that can move independently to detect acoustic stimuli. They use their ears to listen for predators and to locate insect prey. (Schall, et al., 2017)

• Communication Channels
• visual
• acoustic
• chemical

• Other Communication Modes
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Lesser galagos have diets that consist primarily of plant exudates (gums and saps), but also include invertebrates, fruits, and seeds. The primary source of gum comes from acacia plants (genus Acacia). Gum mostly contains carbohydrates and water, with small quantities of fiber, protein, and minerals. It is likely that lesser galagos have special physiological mechanisms to digest gum and sap. The front teeth on their bottom jaws are adapted to scrape gum from tree surfaces. Lesser galagos eat insects more frequently in the summer, when insect numbers are highest. More of their diet is comprised of gum in the winter, when insects are less abundant. The particular plant and insect species included in the diets of lesser galagos varies between species. (Bearder and Martin, 1980; Harcourt, 1986)

• Primary Diet
• carnivore
  • insectivore
• herbivore
  • frugivore
  • granivore
• omnivore

Predation

Lesser galagos serve as prey for a variety of snakes, raptors, and mammalian carnivores. Lesser galagos are most susceptible to predation during the day, when they are resting. They have no active defenses against predators, instead relying on their cryptic coloration and behavioral strategies to avoid detection. Lesser galagos have large eyes and ears, and a well-developed sense of smell, all of which help them detect approaching predators. They are capable of moving quickly between trees, which also helps them evade predators if they are detected. To reduce their chances of being detected while resting, lesser galagos often choose sleeping sites in areas that allow them to remain hidden, but provide them escape routes from predators. (Ellison, et al., 2019)

• Known Predators

  • Snakes (suborder Serpentes)
  • Diurnal raptors (order Falconiformes)
  • Owls (order Strigiformes)
  • Viverrids (family Viverridae)
  • Cats (family Felidae)
  • Caniform carnivores (suborder Caniformia)
  • Primates (order Primates)

Ecosystem Roles

Lesser galagos feed on gums and saps that exude from holes in trees created by insects. Lesser galagos also eat other plant material, including fruits and seeds, and thus may serve as seed dispersers for various plant species. They also eat insects and therefore may play a role in controlling populations of prey species.

Lesser galagos serve as prey for diurnal raptors, owls, snakes, and larger mammals, including viverrids, cats, and other primates. There is limited information regarding parasites that may use lesser galagos as hosts. (Bearder and Martin, 1980; Gron, 2008; Harcourt, 1986)

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Lesser galagos are a small, charismatic primate species that attract tourists. They are also part of the illegal exotic pet trade. Lesser galagos are relatively understudied, so many research groups are actively studying them to gather more knowledge. Lesser galagos may also help control populations of insect pests and likely aid in seed dispersal of native plants. (Bailey and Keene-Young, 2020; Gron, 2008)

• Positive Impacts
• pet trade
• ecotourism
• research and education
• controls pest population

Economic Importance for Humans: Negative

Although lesser galagos are not considered a common nuisance species, they occasionally shelter in man-made structures. They also have the potential to bite or spread disease to humans when kept as pets. (Bailey and Keene-Young, 2020; "Lesser Bush Baby", 2022)

• Negative Impacts
• injures humans
  • causes disease in humans

Conservation Status

According to the IUCN Red List, populations of lesser galagos are considered to be stable or slightly decreasing, depending on the species. However, as humans further encroach on natural areas, the habitat available to lesser galagos decreases. Although there are no efforts directed towards conserving lesser galagos specifically, several species have geographic ranges that include protected areas, such as national parks. ("Lesser Bush Baby", 2022)

• IUCN Red List [Link]

  Not Evaluated

Contributors

Melissa Weiner (author), Colorado State University, Galen Burrell (editor), Special Projects.

References

2013. Animals of the Masai Mara. Princeton: Princeton University Press. Accessed September 13, 2022 at https://doi-org.ezproxy2.library.colostate.edu/10.1515/9781400844913.117.

2022. "Lesser Bush Baby" (On-line). African Wildlife Foundation. Accessed November 13, 2022 at https://www.awf.org/wildlife-conservation/lesser-bush-baby.

iNaturalist Network. 2022. "Lesser Galagos (Genus Galago)" (On-line). iNaturalist. Accessed November 18, 2022 at https://www.inaturalist.org/taxa/43560-Galago.

Austad, S. 1997. Small Nonhuman Primates as Potential Models of Human Aging. ILAR Journal, 38: 142-147. Accessed October 14, 2022 at https://doi.org/10.1093/ilar.38.3.142.

Bailey, A., R. Keene-Young. 2020. "Bush Baby Tenants | Backyard Nature" (On-line video). Youtube. Accessed November 09, 2022 at https://www.youtube.com/watch?v=Ehnc7fJOxPk.

Barnes, K. 2016. Animals of Kruger National Park. Princeton: Princeton University Press. Accessed September 13, 2022 at https://doi-org.ezproxy2.library.colostate.edu/10.1515/9781400880690.

Bearder, S., R. Martin. 1980. Acacia gum and its use by bushbabies, Galago senegalensis (Primates: Lorisidae). International Journal of Primatology, 1: 103-128. Accessed November 09, 2022 at https://link.springer.com/article/10.1007/BF02735592.

Doyle, G., R.D. Martin. 1979. The Study of Prosimian Behavior. Cambridge, MA: Academic Press. Accessed November 09, 2022 at https://doi.org/10.1016/B978-0-12-222150-7.50010-6.

Ellison, G., A. Wolfenden, L. Kahana, A. Kisingo, J. Jamieson, M. Jones, C. Bettridge. 2019. Sleeping Site Selection in the Nocturnal Northern Lesser Galago (Galago senegalensis) Supports Antipredator and Thermoregulatory Hypotheses. International Journal of Primatology, vol. 40, no. 2: pp. 276-96. Accessed September 13, 2022 at https://doi.org/10.1007/s10764-019-00085-y.

Fleagle, J. 2013. Primate Adaptation and Evolution (Third Edition). Cambridge, MA: Academic Press. Accessed September 29, 2022 at https://doi.org/10.1016/B978-0-12-378632-6.00004-5.

Foley, C., L. Foley, A. Lobora, D. De Luca, M. Msuha, D. Tim R.B., S. Durant. 2014. A Field Guide to the Larger Mammals of Tanzania. Princeton: Princeton University Press. Accessed September 13, 2022 at https://doi-org.ezproxy2.library.colostate.edu/10.1515/9781400852802.

Gron, K. 2008. "Lesser bushbaby" (On-line). Wisconsin National Primate Research Center. Accessed September 13, 2022 at https://primate.wisc.edu/primate-info-net/pin-factsheets/pin-factsheet-lesser-bushbaby/.

Groves, C. 2021. "Integrated Taxonomic Information System" (On-line). Accessed September 13, 2022 at https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=572802#null.

Harcourt, C. 1986. Seasonal variation in the diet of South African Galagos. International Journal of Primatology, 7: 491-506. Accessed November 09, 2022 at https://link.springer.com/article/10.1007/BF02693660.

Nowack, J., M. Wippich, N. Mzilikazi, K. Dausmann. 2012.

Surviving the Cold, Dry Period in Africa: Behavioral Adjustments as an Alternative to Heterothermy in the African Lesser Bushbaby (Galago moholi)

Pozzi, L., T. Disotell, J. Masters. 2014. A multilocus phylogeny reveals deep lineages within African galagids (Primates: Galagidae). BMC Evolutionary Biology, 14: 72. Accessed September 13, 2022 at https://doi.org/10.1186/1471-2148-14-72.

Schall, J., W. Zinke, J. Cosman, M. Schall, M. Paré, P. Pouget. 2017. On the Evolution of the Frontal Eye Field: Comparisons of Monkeys, Apes, and Humans. Evolution of Nervous Systems (Second Edition), Volume 4: 249-275. Accessed November 03, 2022 at https://doi.org/10.1016/B978-0-12-804042-3.00130-5.

Scheun, J., N. Bennett, J. Nowack, A. Ganswindt. 2016. Reproductive behaviour, testis size, and faecal androgen metabolite concentrations in the African lesser bushbaby. Journal of Zoology, 301/4: 263-270. Accessed October 21, 2022 at https://doi-org.ezproxy2.library.colostate.edu/10.1111/jzo.12420.

Williams, C. 2015. Fowler's Zoo and Wild Animal Medicine, Volume 8. Amsterdam, Netherlands: Elsevier Inc.. Accessed September 29, 2022 at https://doi.org/10.1016/C2012-0-01362-2.