SPECTACLED LESSER GALAGO

Galago matschiei

Geographic Distribution and Habitat

The spectacled lesser galago (Galago matschiei), also known as the dusky galago, dusky bushbaby, lesser needle-clawed galago, Matschie’s galago, and spectacled galago, is a small, nocturnal Old World primate. They primarily live in the area of the Albertine rift, a section of Africa along the borders of the Democratic Republic of the Congo, Uganda, Rwanda, Burundi, Tanzania, and Zambia, characterized by a series of large freshwater lakes. Spectacled lesser galagos are in good company in this area, as it is one of the most biodiverse regions in Africa, home to more than half of Africa’s birds, 40% of its mammals, and 20% of its amphibians and plants. Their ideal habitat is primary and secondary lowland, mid-altitude, montane, and bamboo forests, and they especially like forests where Guinea plums (Parinari excelsa) are the primary tree.

Despite being a common species, spectacled lesser galagos are understudied because they are shy and difficult to observe.

TAXONOMIC NOTES

The exact makeup of the spectacled lesser galago family tree is a subject of debate. Depending on who you ask, spectacled lesser galagos share their family, Galagidae, with four to six genera and 11 to 19 species of bushbabies and galagos. Galagidae is sometimes considered a subfamily within Lorisidae, the family of lorises and pottos. Molecular analysis suggests that spectacled lesser galagos may be the most genetically unique of all the species in their genus.

Spectacled lesser galago geographic range. IUCN, 2019

Size, Weight, and Lifespan

Galagos are quite small, ranging from 3 to 11 oz (95–300 g) in weight and 3.6 to 8 inches (9–20.5 cm) in head and body length, with their tail adding an additional 4–11 inches (11–28 cm). Spectacled lesser galagos are about in the middle in terms of size for galagos, though exact figures are unknown.

Exact lifespan is unknown, but based on other galagos, it is likely approximately 3 to 4 years in the wild and up to 13 in captivity.

What Does It Mean?

​Omnivorous:
Having a diet that consists of food of both plant and animal origin.

Toilet claw:
A specialized grooming claw common to prosimians and certain other primates.

Visit the Glossary for more definitions

Appearance

Spectacled lesser galagos are medium-sized for galagos, with dark-brown hair over most of their body. Their ears are tall and black. The most characteristic feature of spectacled lesser galagos, like other nocturnal primates, is their extremely large amber eyes that help them to absorb as much light as possible in dark nighttime forests. As their name suggests, spectacled lesser galagos have “spectacles” of dark hair framing their eyes, which continue down in thin bands, connecting at the nose and giving the appearance of glasses. They have a white nose stripe that extends to the forehead. Their stomach, throat, and insides of their legs are pale gray, while their back and upper legs are dark gray-brown. Their tail is long and is often held coiled when sitting. Their hind legs are noticeably longer than their forelegs, and their hind feet, like most other strepsirhines, include toilet claws. Their nails have a ridge that runs vertically down the length of the nail, and end in a sharp point. This is similar to species of a related genus, Euoticus, composed of the needle-clawed galagos, although this nail ridge isn’t quite as pronounced on spectacled lesser galagos (though they are still sometimes referred to as lesser needle-clawed galagos). They display no sexual dimorphism and infants are born with their adult coloration.

Photo credit: Nik Borrow/Flickr/Creative Commons
Diet

​As omnivores, spectacled lesser galagos feed on insects, flowers, fruit, and tree gums. The specific breakdown of their diet beyond this is not well understood, although gums may be a more important food source during droughts when other food is difficult to come by.

Behavior and Lifestyle

Arboreal (tree-dwelling) and nocturnal (active at night), spectacled lesser galagos are well adapted to moving swiftly through dark forests. They can leap up to 40 feet (12m) between branches. This differentiates galagos from their cousins, the lorises, who move slowly and rarely jump. Spectacled lesser galagos tend to stick to the mid-canopy and spend their days sleeping amidst thick vegetation, or in hollow tree trunks, tree forks, or old birds’ nests. While they are extremely agile and swift at night, if disturbed during the day, they usually react with slow movements (and wouldn’t you, too, if you were suddenly woken up?).

Fun Facts

Lesser galagos regularly urinate on their hands and feet, which is thought to help their grip and may be a form of scent marking.

Daily Life and Group Dynamics 

Galagos are often found in small groups of seven to nine individuals, although their group dynamics are woefully under-studied. They usually sleep as a group but forage at night alone. They maintain individual home ranges, and males’ are usually larger than females’. A single male’s home range may overlap with multiple females’.

Communication

Spectacled lesser galagos communicate vocally, using “churs” to communicate with their groupmates. To express anxiety, they use a variety of grunts and shrieks. Visual communication is typically in the form of facial expressions and body postures to communicate emotions such as fear and aggression. Tactile communication is very important, especially between a mother and her offspring and between mates. Spectacled lesser galagos may also use urine for scent marking.

Reproduction and Family

Galagos usually breed polygynously, with males competing for access to the home ranges of several females. They breed twice per year, once in November as the rainy season begins, and again in February as the season ends. They typically have one or two, or even sometimes three, offspring at at time. The infants are born from April to November after a 110 to 120 day gestation. The infants nurse from their mothers for about three and a half months, although they start to explore solid food when they are about a month old. Very young spectacled lesser galagos cling to their mothers, or are carried in her mouth by the napes of their necks. Usually, a mother leaves her offspring unattended in a safe place while she forages. It is unknown what role, if any, males play in rearing offspring.

Photo credit: Nik Borrow/Flickr/Creative Commons
​Ecological Role

Likely predators of spectacled lesser galagos include small cats, snakes, and owls. Some species in Galago have been known to group together to fend off small predators. As fruit eaters, spectacled lesser galagos may play a role in seed dispersal.

Conservation Status and Threats

Spectacled lesser galagos are designated as Least Concern by the International Union for Conservation of Nature (IUCN, 2019). They are a widespread species and are even common in some parts of their range.

That said, spectacled lesser galago habitat is declining, and at risk of degradation, fragmentation, and loss due to expanding human populations. Some areas of the Albertine Rift have extremely high population densities—up to 2,560 people per square mile (1,000 people per square kilometer). As a result, spectacled lesser galagos’ population is in decline, albeit slowly.

Climate change is also expected to have a profound impact on the Albertine Rift region. The mountains, rivers, and lakes of the region make for a strikingly beautiful topography, although they exacerbate the impacts of climate change on species. As the climate warms, species will need to move up in elevation in order to find suitable habitat. In the Albertine Rift region, they will move up towards the mountains, where the overall area of suitable habitat will be lower.

​Conservation Efforts

Spectacled lesser galagos are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES). They have access to a number of protected areas, including the Bwindi Impenetrable National Park in Uganda, Nyungwe National Park in Rwanda, and the Kibira National Park in Burundi. The Albertine Rift region, where most spectacled lesser galagos reside, is recognized as an extremely important biodiversity hotspot, and is protected to varying degrees as a Global 200 Ecoregion and an Endemic Bird Area. Scientists are continuing to advocate for this region as an important biodiversity hub deserving of increased protections. A 2016 report by the Wildlife Conservation Society proposes a $21 million per year conservation plan that focuses on areas that are not already protected. While that might sound expensive, the Albertine Rift is so diverse that this comes out to a cost of only $2,500 per species annually—a steal considering that such imperiled species as mountain gorillas, forest elephants, and chimpanzees rely on this area. Ensuring that this important ecoregion is protected will help keep spectacled lesser galagos at “least concern” and may help recover populations of Africa’s most imperiled primates.​

​References:
  • https://www.iucnredlist.org/species/8787/17963414#population
  • https://albertinerift.wcs.org/
  • https://animaldiversity.org/accounts/Galago_senegalensis/
  • https://www.wildsolutions.nl/vocal-profiles/galago/matschiei/
  • https://animaldiversity.org/accounts/Galagidae/
  • Beolens, B., M. Watkins, M. Grayson. 2009. The Eponym Dictionary of Mammals. JHU Press.
  • https://books.google.com/books?id=I-kSmWLc6vYC&pg=PA264#v=onepage&q&f=false
  • Kingdon, J., et al. 2013. Mammals of Africa, Volume 2. A&C Black.
  • https://books.google.com/books?id=B_07noCPc4kC&pg=PA437#v=onepage&q&f=false
  • Mongabay. 2018. East Africa’s Albertine Rift needs protection now, scientists say. Accessed 5 Feb 2021 at: https://news.mongabay.com/2018/02/east-africas-albertine-rift-needs-protection-now-scientists-say/
  • Off, E.C. and D.L. Gebo. 2005. Galago locomotion in Kibale National Park, Uganda. Am. J. Primatol., 66: 189-195. https://doi.org/10.1002/ajp.20137
  • Plumptre, A.J., S. Ayebare, D. Segan, J. Watson, D. Kujirakwinja. 2016. Conservation Action Plan for the Albertine Rift. Wildlife Conservation Society. Accessed 5 Feb 2021 at:
  • https://albertinerift.wcs.org/About-Us/News/articleType/ArticleView/articleId/10950/Conservation-Action-Plan-for-Albertine-Rift-identifies-key-sites-and-species.aspx

Written by K. Clare Quinlan, February 2021