Garnett’s Greater Galago, Otolemur garnettii
GARNETT'S GREATER GALAGO
Geographic Distribution and Habitat
The Garnett’s greater galago, also known as the northern greater galago, Garnett’s bushbaby, or small-eared greater galago, is found in East Africa. They range from the southern half of Somalia to Tanzania, and are also found on the island of Zanzibar.
Garnett’s greater galagos prefer the middle to high canopies in coastal, riverine, and highland forests. Occasionally, they wander into farmland plantations.
Throughout their range, the Garnett’s greater galago is sympatric with the Zanzibar bushbaby (Paragalago zanzibaricus), the Kenya coast galago (Paragalago cocos), the Senegal galago (Galago senegalensis), Grant’s bushbaby (Paragalago granti), and occasionally the brown greater galago (Otolemur crassicaudatus).
There are four Garnett’s greater galago subspecies:
- The Zanzibar small-eared galago, Otolemur g. garnettii, is endemic to Zanzibar, Pemba, and Mafia Islands, Tanzania.
- The Pangani small-eared galago, Otolemur g. panganiensis, ranges from Kenya to northern Mozambique.
- The white-tailed small-eared galago, Otolemur g. lasiotis, ranges from southern Somalia, along the Kenya coast, to northern Tanzania.
- The Kikuyu small-eared galago, Otolemur g. kikuyuensis, is endemic to the Central Kenya Highlands.
Size, Weight, and Lifespan
The Garnett’s greater galago is a relatively small primate. Adult males are slightly larger than females, weighing 1.75 pounds (794 g), and adult females weigh 1.62 pounds (175 g). Total body length averages 10.5 inches (26.6 cm). Their tails, which are longer than their bodies, average 14.3 inches (36.3 cm).
Compared to other members of the genus Otolemur, Garnett’s greater galagos have a short ear length, which on average measures 1.7 inches (4.3 cm).
Garnett’s greater galagos can live up to 15 years.
The Garnett’s greater galago can be distinguished by the color of their pelage. Their faces are mainly covered in a uniform color (gray or brown). Most of their bodies are covered in red to gray-brown colored fur, with slight greenish tones. They have black hair on the lower half of their tail and their fur is thick and soft.
They have rounded heads with large ears, forward facing eyes, and a slightly pointed snout. Their ears can be flexed and folded as needed to detect the slightest sounds coming from any direction. Their eyes have a special reflective, or mirror-like, layer at the back of their retina (the light-receiving part of the eye) that enables them to see in very dim light and makes their eyes shine in the dark like a cat’s eye.
Garnett’s greater galagos have larger hind limbs than forelimbs. Their hind legs and anklebones are very strong, enabling them to move accurately and quickly through the trees.
Their slim fingers and toes have round flat pads of thickened skin that help them grip firmly onto branches and tree trunks. All digits have nails, except the second digit on the hind foot, which has a long claw for grooming also known as a “toilet claw.”
The teeth of Garnett’s greater galagos are unique. They have a tooth-comb made up of their lower incisors and canines, which is also used for grooming and cleaning.
The Garnett’s greater galago can be considered omnivorous, primarily feeding on insects and fruit. About half of their diet is fruit and half is insects.
When resources are scarce, especially in the winter, they sometimes eat tree gums, which are high in fiber, protein, calcium, magnesium, and potassium. Gums are difficult to digest, but their specialized gastro-intestinal tract contains bacteria that is designed to break it down.
Behavior and Lifestyle
Nocturnal and arboreal primates, Garnett’s greater galagos hide in the middle- to high-canopy during the day to avoid predators like large snakes and hawks. They can be found sleeping in vine tangles, tree holes, thick vegetation, or old bird nests. Males tend to sleep alone while females sleep with their offspring. Both sexes are relatively solitary; however, they occasionally engage in play. They climb and run quadrupedally on branches. They also engage in bipedal hopping by jumping and landing on their hind limbs first, similar to a kangaroo.
Garnett’s greater galagos can jump up to 6.6 feet (2 m) in the air, thanks to very elastic joints in their lower legs.
The body of the Garnett’s greater galago is covered with thick, wool-like fur.
Galagos’ ears have four ridges and are very pliable. They can move each ear independently.
Daily Life and Group Dynamics
Garnett’s greater galagos live in small groups mainly consisting of a male, females, and offspring. The adult male does not sleep in the group sleeping nest. He only has contact with females when they are outside of the sleeping nest.
Compared to females, males disperse further from the area in which they were born and usually do so at an early age. Males are often solitary foragers and transient members of groups, meaning they only stay in a group for a short period of time.
Females remain in their natal areas, but same-aged females do not share overlapping ranges. Related females are usually the only individuals that share a common home range. This can be due to the fact that Garnett’s greater galagos rely heavily on fruit. The abundance and quality of fruit in trees and patches vary throughout the year. This can cause unrelated individuals to exclude others from parts of the forest, especially if they are under pressure or if resources are limited.
Both female and male Garnett’s greater galagos are highly vocal. Researchers have been able to identify the calls based on their function, such as alarm calls, distress calls, infant click calls, and mating calls. Their most distinguished call can be heard up to 400 feet (122 m) away and lasts for about 5 seconds.
Foot rubbing is used as a form of communication. Individuals rub their feet against other materials to produce sounds that can vary in intensity. The sound produced blends in with the background noise of the forest. Thus, foot rubbing allows individuals to communicate with one another and protect themselves without alerting predators. Males have also been observed to use foot rubbing in aggressive encounters with other males.
Olfactory signals serve as another form of communication. Garnett’s greater galagos engage in urine-washing (males more so than females), by urinating on their hands and feet. This allows them to leave their scent on branches, vines, leaves, and anything else they touch. In addition, individuals also communicate by sniffing one another.
Reproduction and Family
Their mating system can be described as promiscuous or polygamous since both males and females have multiple mates. The act of mating can last up to 120 minutes. Some researchers suggest that the long duration of mating is one way males can guard females from other males.
Females typically give birth once per year, generally between August and October, and usually to one offspring. Both males and females mature at about 20 months old. Weaning occurs after approximately 3 months.
Mothers provide most of the parental investment. Unusually for most primates, they carry their infants with their mouths. While foraging, they leave the infant in a nest, a practice known as “parking.” As the infant gets older, he or she rides on the mother’s back as she searches for food. While eating, she will place her infant onto a branch to which the infant clings while Mom enjoys her meal. Before weaning, mothers provide infants with nutrient-rich milk and protect them against predators and other dangers.
In the forests of East Africa, Garnett’s greater galagos have an important role, since they eat tons of insects and fruit. They serve as seed dispersers for a variety of plant species and help maintain the insect population.
Garnett’s greater galagos are listed as Least Concern by the International Union for Conservation of Nature’s Red List of Threatened Species (IUCN, 2016). Although they are listed as Least Concern, their populations are decreasing from habitat loss, fragmentation, and degradation.
The Garnett’s greater galago is threatened by the conversion of natural habitat to agricultural land, logging, and fuelwood collection, as well as the expansion of human settlements and tourism. They are killed as a presumed agricultural pest and as symbols of bad luck. In the Southwest of Tanzania, they are hunted for bushmeat and in Zanzibar they are trapped for dog food. They have also been observed to be for sale as pets in Kenya and Tanzania, as well as recorded in the international pet trade for sale in the United Arab Emirates.
Garnett’s greater galago is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES). They can be found in a number of protected areas and National Parks throughout Kenya, Tanzania, and Zanzibar.
More conservation actions are needed to protect Garnett’s greater galagos and their regions. Actions such as site and area management and monitoring populations can assist in ensuring the Garnett’s greater galago stays at “least concern,” and may help recover populations and restore their habitats.
- Bearder, S.K. 1989. Lorises, Bushbabies, and Tarsiers: Diverse Societies in Solitary Foragers. Primate Societies. University of Chicago Press, Chicago. 11-24.
- Hager R., Welker, C. 2001. Female Dominance in African Lorises (Otolemur garnettii). Folia Primatol. 72:48-50.
- Harcourt, C. S. and Perkin, A.W. 2013. Otolemur garnettii small-eared greater galago. In: T. M. Butynski, J. Kingdon and J. Kalina (eds), Mammals of Africa. Volume II: Primates. 413-416.
- Nash. L.T. and Harcourt, C.S. 1986. Social Organisation of Galagos in Kenyan coastal forests: II Galago garnettii. American Journal of Primatology 10: 357-369.
Written by Tara Covert, February 2021