Galago demidoff

Geographic Range

Galagoides demidoff , commonly called Demidoff's bushbaby, is widely found in west and central equatorial Africa. Common in this large range, G. demidoff is found from the southern borders of Somalia to northeastern Tanzania, and from Senegal to western Tanzania. Population density for G. demidoff is usually between 50 to 80 per sq km, though depending on the quality of appropriate habitat, up to 117 individuals have been observed in a 1 square km plot.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

Habitat

Demidoff’s bushbabies can be found in either primary or secondary rainforests. Due to their small size, these animals can live in the dense foliage of the forest where other prosimians would have a great deal of difficulty moving. They prefer biotope zones with fine branches and/or liane curtains, where the diameters of their supports are generally less than 5 cm. In primary forests, this area is high in the canopy (5 to 40 m). In secondary forests, and in tree fall zones in primary forests, they are usually found in bushy vegetation only a few meters (0 to 5 m) off the ground. They can often be seen in the dense vegetation by the roadside and in ditches.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Galagoides demidoff is the smallest primate found in Africa. The head and body length is between 105 and 123 mm, and the tail is 150 to 205 mm long. Demidoff's bushbabies weigh between 46 and 88 gm. The color of the dorsal fur varies from bright gingery to gray-brown, whereas the fur on the ventrum is a paler tan. The ears are relatively short, un-furred, and mobile, and the nose is pointed and upturned. Demidoff's bushbabies have a distinct white stripe running between the eyes, down the nose.

The genus Galago is noted for its leaping ability. Both the length of the hind limbs, which are much longer than the forelimbs, and the elongation in the tarsal region in the foot, assist in locomotion. When running, the hind limbs of G. demidoff exert the most force, working to propel the body, while the fore limbs mainly provide support and stability. In the type of habitat these animals inhabit, this division between the limbs is necessary. The branches used by G. demidoff tend to be thin and unstable, which can throw an individual off balance. Thus it is necessary for these animals to use their forelimbs and long tails to maintain equilibrium. Keeping well balanced is important for these animals because they use running and leaping equally in their locomotion.

Vision in G. demidoff is very well developed, a trait that is essential in animals which rely on arboreal leaping. Galagoides demidoff can leap 1.5 to 2 meters between branches, without losing any height. Leaping allows rapid movement between locations, but requires a shock-absorbing mechanism. In G. demidoff , the forelimbs reach a substrate first and absorb most of the impact. This allows the hind limbs to quickly prepare to leap again.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Although mainly polygynous, the mating system of G. demidoff is flexible, and depends upon the home range of the individual animal. For example, an individual male may be monogamous if his territory includes that of only one female. However, males typically have a home range which overlaps that of several females, and so they are polygynous.

• Mating System
• monogamous monogamous
• polygynous polygynous

Female G. demidoff generally have only one pregnancy per year. The breeding season for Demidoff's bushbabies is dependent on the area in which they are found. In the Congo, births occur between September and October and between January and February. In Gabon, births occur all year round, although there is an increase between January and April when there is an abundance of fruits and insects. This species generally produces a single offspring per pregnancy, although twins do occur.

Gestation in G. demidoff is between 111 and 114 days, and lactation lasts for approximately 45 days. Newborns weigh between 5 and 10 g. New mothers isolate themselves for a one or two week period, though siblings and the dominant male are permitted to approach the newborn a few hours after the birth. When the young bushbaby is a few days old, the mother takes it out of the nest, leaving it hidden in the dense vegetation while she forages, before carrying it back to the safety of the nest as dawn approaches.

Young G. demidoff are weaned after 2 months and reach adult size around 6 months of age. After weaning, the young still get some help in foraging. Because their prey-capture responses are not fully developed, the young of this species require assistance in order to find and acquire food. Young bushbabies follow an adult (usually the mother, another female in the group, or a dominant male) out as they hunt. This helps them to locate prey. Demidoff’s bushbabies reach sexual maturity 8 to 10 months after birth.

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

Females provide most of the care for offspring. As in most primates, this includes nursing the young, grooming them, protecting them, and playing with them. The role of males in offspring care has not been documented, but may include grooming and protection. Although males are not "active" in this role, the young do follow them while foraging, allowing the young animals to find food.

• Parental Investment
• no parental involvement
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • female
• post-independence association with parents
• extended period of juvenile learning

Lifespan/Longevity

In captivity, G. demidoff often live over 6 years, with a maximum recorded lifespan of 13 years. In the wild, experiments have shown that the entire population can replace itself after a 6-year period, with most individuals living 4 to 5 years.

Behavior

Galagoides demidoff is a crepuscular/nocturnal species. During the day, G. demidoff sleeps in a leaf-nest created by an individual in suitably dense vegetation. Females and juveniles generally share a sleeping site, whereas males often sleep alone. Arising about a half-an-hour before night falls, G. demidoff engages in a period of self-grooming, yawning, and stretching. Demidoff's bushbabies begin to exit the nest and search for food only after the light intensity reaches a point between 150 to 20 lux.

Both the males and females of G. demidoff are mostly solitary animals. Field observations indicate that during the active hours of the night, G. demidoff spends 75% of the time isolated, 21% in pairs, and 2% or less in groups of 3, 4, or 5.

Interspecific behavior: Prosimians are rarely, if ever, aggressive in interspecies encounters. If two species meet in the presence of food, the larger (or if the same size, the quicker of the two species) makes off with the food. Due to species separation into the different stratifications of the forest, and hence specializations in different types of prey items, encounters between species are unlikely.

• Key Behaviors
• arboreal arboreal
• saltatorial saltatorial
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• sedentary sedentary
• territorial territorial
• social social

Home Range

Both male and female G. demidoff establish home ranges, with males ranging between 0.5 and 2.7 ha, and females 0.6 and 1.4 ha. Adult males are territorial, each seeking a home range that overlaps those of several females. Males can be aggressive toward one another, and intense competition may result. Females, though, can form groups, and several related females might share a home range. Adults of opposite sexes, though not foraging together, may have contact during the night, and sometimes sleep together by day.

Communication and Perception

Galago demidoff individuals communicate in a variety of ways. Visual signals are used to communicate such things as submission, aggression, fright, and excitement. Specific posturing is also used to indicate an acceptance of grooming or mating activities. All age groups within the species use visual signals.

Demidoff’s bushbabies also use vocalizations to communicate with conspecifics. Six distinct types of calls have been defined within G. demidoff communication. Gathering calls are mainly heard as dawn approaches and the individuals are attempting to re-group at a sleeping site or particular leaf nest. The "rolling call" is used to communicate after the group has reassembled. This call can also be connected with adults seeking contact with each other. "Plaintive squeaks" are generally associated with sexual relationships between males and females. "Alarm calls" are the most common type of G. demidoff vocalization. While used spontaneously upon awakening, these calls are uttered only occasionally throughout the night, often in response to such things as strange noises, encountering a predator, or an unknown conspecific, etc. A "threat call" is used by an individual to intimidate a conspecific. The latter will generally flee from the confrontation. And finally, the "distress call" is used after an individual has been captured or injured. It is important to note that adults sometimes approach the young of other Galago species if they are uttering distress calls.

Galagoides demidoff also uses olfactory cues for both direct and indirect communication. Indirectly, they use urine marking to signal such things as gender, and sexual readiness. These animals mark their surroundings with scrotal and vulval glands when involved in mating behavior. Direct olfactory communication is important when individuals encounter one another. During these interludes, facial and genital regions are subject to intensive investigation.

As with many primate species, allogrooming is an important part of social dynamics. This tactile communication is preformed through licking and using the ‘toothcomb’ (composed of the four lower incisors and the procumbent two canines) to cleanse another individual. Most often occurring between a mother and her offspring, allogrooming can also occur between adults in an established social group. Allogrooming takes place most frequently during the time period just after these animals awaken, or just after they return to their sleeping site. The other form of tactile communication occurs in ‘contact groups’, where several individuals sleep entwined at a single nest site throughout the day.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Demidoff’s bushbabies are primarily insectivores; 70% of their diet is composed of insects, mostly small beetles (45%), nocturnal moths (38%), and caterpillars (10%). They also consume fruits (19% of their diet) and gums (10%). Because of their small size, they can feed almost exclusively on prey items, whereas the other species of galagos must rely on vegetation to make up a greater portion of their diets.

The composition of the diet changes depending upon the time of feeding. Demidoff’s bushbabies feed predominately on fruits and gums when they initially arise during the early hours of the night (18.30 to 24.00). During this time period, fruits and gums make up 35% of their diet. During the later hours of the night, from 24.00 to 6.00, such foods make up only 20% of the diet. Demidoff’s bushbabies generally eat fruit slowly, using their tooth scrapers to pick off tiny pieces. They never consume the kernels. Fruits often come from trees of the genus Uapaca , or from parasol trees, Musanga cecropiodes . Observations from the wild suggest that the gums consumed by G. demidoff come from only five tree species: Entada gigas , Entada celerata , Penacletra eetveldeana , Piptadenstrum africanum , and Albizia gummifera .

Demidoff’s bushbabies locate prey using auditory and visual cues, and often will capture an insect just as it takes off. The disturbance caused by a bush baby’s locomotion through the canopy causes the prey to flee. This movement cues a bushbaby to the prey’s location. Prey can escape detection by remaining immobile, but as soon as the slightest movement occurs, a bushbaby can spot the insect. Bushbabies do this by directing their ears in the correct direction and localizing the sound. Experiments have shown that G. demidoff is so good at localizing sounds that individuals can follow the exact movements of a flying locust from the other side of a plywood screen. Demidoff's bushbabies move their heads, just as they would if they could actually see the insect. This ability to track insects is highly adaptive, as bushbabies usually hunt in the dense foliage of invading lianes.

In order to actually catch prey during take off, Demidoff's bushbabies will firmly grasp a branch with the hind feet, and then thrust the body forward towards the prey. Once the insect has been captured, G. demidoff will recoil immediately to its starting position.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• insects

• Plant Foods
• fruit
• sap or other plant fluids

Predation

Birds of prey, vipers, and humans all hunt this species as a source of food.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Information on this topic is not available in the literature. However, we can assume that as insectivores, these animals exert an impact on the populations of prey insects. As part of their fruit eating behavior, it is likely that these animals help to disperse seeds. To the extent that any other species relies upon Demidoff's bushbabies for food, they may also have an impact upon predator populations.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Local woodsmen and families at times hunt G. demidoff for use as a food source. Hunters sometimes mimic the distress calls of young Galago to attract adults.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

It is unlikely that these animals have any negative impact on human populations.

Conservation Status

Though considered vulnerable by many scientific groups, G. demidoff is not listed as an endangered species. Like all primates, G. demidoff is listed on CITES appendix II.

Other Comments

Demidoff's bushbabies were previously recognized under the name Galagoides demidoff .

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Christie Sampson (author), Michigan State University, Barbara Lundrigan (editor, instructor), Michigan State University.

References

Charles-Dominique, P. 1977. Ecology and Behaviour of Nocturnal Primates . Great Britain: Gerald Duckworth & Co Ltd.

Lindenfors, P. 2002. Sexually antagonistic selection on primate size. Journal of Evolutionary Biology , 15, (4): 595-607. Accessed March 11, 2004 at http://www.primate.wisc.edu/pin/jeb422.html .

Napier, J., P. Napier. 1967. A Handbook of Living Primates . New York, New York: Academic Press.

Napier, J., P. Napier. 1985. The Natural History of Primates . England: British Muesum (Natural History).

Nowak, R. 1997. "Walkers Mammals of the World Online 5.1" (On-line). Dwarf Galagos. Accessed March 11, 2004 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/primates/primates.lorisidae.galagoides.html .

Bioko Biodiversity Protection Program. 1998. "Bioko Biodiversity Protection Program" (On-line). Demidoff's Galago. Accessed March 12, 2004 at http://www.bioko.org/primates/demidoff.asp .

World Wildlife Fund. 2001. "World Wildlife Fund: WildWorld" (On-line). Western Congolian swamp forests (AT0129). Accessed March 11, 2004 at http://www.worldwildlife.org/wildworld/profiles/terrestrial/at/at0129_full.html .