Goodman’s Mouse Lemur, Microcebus lehilahytsara
GOODMAN'S MOUSE LEMUR
Microcebus lehilahytsara
Geographic Distribution and Habitat
The Goodman’s mouse lemur is primarily found in the Andasibe region of eastern Madagascar. They occur as far west as Ambohitantely Special Reserve, as far north as Marojejy National Park, and as far south as the Onive/Mangoro River complex.
Within their range, they are mainly found in rainforests, although some individuals have been observed in patches of old eucalyptus plantations. In the Central Highlands of the island, they can be found in small old-growth forest fragments surrounded by a forest-grassland savannah mix. At Ambavala and Anjiahely, their northern range, they are found in forest habitats of varying degrees of degradation. They are also found within areas of fallow vegetation, a farming technique where cultivable land is left unplanted for one or more cycles. These areas of fallow vegetation are often adjacent to forest edges.
Size, Weight, and Lifespan
The head-body length of the Goodman’s mouse lemur is comparable to that of the Madame Berthe’s mouse lemur (M. berthae). The latter species has an average head and body length of 4.6 inches (11.8 cm) for adult males, and five inches (12.7 cm) for adult females. The average weight of the Goodman’s mouse lemur ranges from 45-48 grams (1.6-1.7 oz), with males slightly larger than females. This difference in size and weight between genders is an example of sexual dimorphism (noticeable physical differences between both genders). They may live up to five years in the wild.
Appearance
Besides their small size, mouse lemurs can be generally characterized by their long, furry tails, large eyes, long fingers, and round bodies and heads. All mouse lemurs have a white strip between their eyes. They are physically adapted to nocturnal life with their large eyes and protruding, flexible ears.
The Goodman’s mouse lemur is mainly dark red with a white underbelly, dark brown eyes, and an orange tint on the back. Their tails have the ability to store fat, a handy technique for surviving torpor in winter (more on that later).
Almost all lemuriforms, the suborder which includes galagos, lemurs, and lorises, have a toothcomb. (The exception is the aye-aye.) A toothcomb is a set of lower-front teeth which are used for grooming.
Diet
The Goodman’s mouse lemur is an omnivore. Their diet consists of insects, small vertebrates, fruits, flowers, nectar, gum, and leaves.
Behavior and Lifestyle
The Goodman’s mouse lemur is nocturnal (active at night) and arboreal (tree-dwelling). From dawn to dusk, they sleep in tree hollows. Along with their fur camouflaging them amongst the trees, these sleeping sites protect them from predators, such as snakes, owls, and fossas. Speaking of sleeping, during the day, Goodman’s mouse lemurs enter a state that occurs both daily and for longer periods during winter known as torpor, which is similar to hibernation. Torpor significantly reduces metabolic rate and body temperature, allowing them to conserve energy and survive periods when food may be scarce. Both sexes enter torpor daily, however, females are more likely than males to enter winter torpor. Younger males are more likely to go into torpor than older males. Males participating in winter torpor wake up around 20 days earlier than the females to prepare for mating.
Upon waking at night, they use their long, delicate limbs to leap from tree to tree, their long tails to balance among the branches, and specialized digits on their hands and feet to securely grip branches. Locomotion is primarily quadrupedally (on all fours) on branches. Nights are spent searching for food and occasionally engaging in social behaviors, such as grooming and mating.
The Goodman’s mouse lemur is named after primatologist Steven M. Goodman. The species name “Lehilahytsara” is a combination of the Malagasy words which mean “good” and “man”.
The Goodman’s mouse lemur is primarily solitary in nature. Males occupy larger home ranges, up to four times larger than those of females. They mark their territories using scent glands, ensuring that there is little overlap between neighboring individuals. Besides these facts, there is not much more information available regarding the social activity of the Goodman’s mouse lemur. More research is clearly needed.
Despite the lack of data, it is known that even the most solitary of mouse lemurs commonly gather in communal sleeping sites, likely to conserve heat. With the information that is known about the Goodman’s mouse lemur’s closest relatives, it can be assumed that closely related females gather in sleeping dens of two to five individuals, while males may sleep with one or more partners. Males and females may also sleep together, especially during the mating season. There is a subtle social order within most species of mouse lemurs, with females often having dominance over males. This social organization becomes more evident in captive populations.
Within the northern reaches of their range, Goodman’s mouse lemurs have been observed cohabitating alongside the Jonah’s mouse lemur (M. jonahi) and the MacArthur’s mouse lemur (M. macarthurii).
Once again, data is lacking specifically on the Goodman’s mouse lemur and must be inferred from closely related species.
From what we know of mouse lemurs as a whole, they are capable of making several different vocalizations, mostly consisting of trills and whistles. These calls include mating calls, predator warnings, trills for their morning reunion at their sleeping sites, and calls potentially meant to signal territorial dominance. Babies have their own repertoire of calls which enable them to stay in contact with their mothers. Some species of mouse lemurs also make ultrasonic calls that cannot be heard by humans without special equipment.
Mouse lemurs use their urine for scent-marking, not only to mark their territory and alert others to their presence but to advertise their reproductive receptivity.
Breeding occurs for the Goodman’s mouse lemur in spring, almost immediately after the conclusion of winter torpor. Females may reproduce from two to four times per year and the gestation period lasts between two and three months. There is no other data available regarding the reproduction specifically of Goodman’s mouse lemurs, but much can be inferred from other mouse lemur species.
If we look at the Gray mouse lemur (M. murinus), after their gestation (pregnancy) period, females typically give birth to one to three offspring, known as pups. Born undeveloped, with closed eyes and weighing only a few grams, and highly dependent on Mom for food and protection, they cling to her fur, camouflaging themselves with their surroundings to avoid predation. For the first few weeks in the big wide world, the pups will remain in their mother’s nest, receiving a constant supply of milk and grooming sessions. As they grow older, the pups become more active and curious about their surroundings, exploring under the watchful eyes of Mom.
Around the age of two to three months, pups begin to gain more independence, venturing out on their own, but still relying on their mother for guidance and protection. She’ll continue to nurse and care for her young until four to five months of age when the pups are fully weaned. As the months go by, Mom teaches vital survival skills to her young, such as establishing territory, foraging for food, and identifying potential threats.
Sexual maturity, and thus, full-fledged independence, is reached at one year of age. However, it may take a bit longer for males to fully develop. From that point on, the newly crowned adults disperse to establish territories of their own.
As insectivores, Goodman’s mouse lemurs serve as pest controllers through their consumption of insects. As part of their diet also consists of fruit, they aid in the regeneration of their forest habitat by dispersing seeds through their feces during their nightly travels. They additionally play a role in pollination. Like bees and butterflies, they collect pollen from flowers while drinking nectar. They then deposit the pollen on each flower they visit, thereby pollinating the plants. Finally, as a prey species, they also play a role in feeding local predators within their habitat.
The International Union for Conservation of Nature lists the Goodman’s mouse lemur as Near Threatened (IUCN, 2022), appearing on the IUCN Red List of Threatened Species.
Like nearly all lemurs of Madagascar, the Goodman’s mouse lemur is threatened by very high rates of habitat loss and degradation. The eastern lowland rainforests in which the mouse lemur lives are threatened in particular by unsustainable farming practices and logging. Charcoal production and mining are additional threats, with the country’s largest mine being located within the species’ range. Repeated vegetation burning has greatly contributed to forest loss in Madagascar’s Central Highlands. The main threats to remaining rainforests further east mainly stem from slash-and-burn agriculture. The Goodman’s mouse lemur is also hunted by humans for bushmeat and the pet trade.
The Goodman’s mouse lemur is listed in Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
They occur in several protected areas within Madagascar, including two National Parks (Mantadia, Marojejy), four Special Reserves (Analamazaotra, Ambohitantely, Marotandrano, Anjanaharibe-Sud), and Makira Natural Park. Some sites where they occur have recently been announced as newly protected areas (e.g., Ankeniheny-Zahamena, Anjozorobe-Angavo, Mangabe-Ranomena-Sahasarotra, Tsinjoarivo, Maromizaha), while others are in the process of becoming protected areas (e.g., Ankafobe, Torotorofotsy), or are managed by local communities for conservation. They are kept in only a few zoological institutions, with a significant breeding colony of several dozen individuals in Zoo Zurich in Switzerland.
Conservation actions needed include proper enforcement of land, water, and site/area management, harvest management practices to curtail hunting, and formal education. In addition, effective communication is necessary in order to facilitate local awareness regarding the plight of the Goodman’s mouse lemur and their role in the local ecosystem. Additional research is also needed on the Goodman’s mouse lemur’s population size, distribution, and trends, life history and ecology, and threats. Further monitoring of their population trends is also needed in order to enable these pint-sized prosimians to avoid moving closer along the path towards endangerment and extinction.
- https://www.alltheworldsprimates.org/Members/Home/MasterPrimate.aspx?tid=748
- https://animalia.bio/goodmans-mouse-lemur
- https://www.bioexplorer.net/animals/mammals/prosimians/goodmans-mouse-lemur/
- https://en.wikipedia.org/wiki/Fallow
- https://en.wikipedia.org/wiki/Goodman%27s_mouse_lemur
- https://en.wikipedia.org/wiki/Madame_Berthe%27s_mouse_lemur
- https://www.iucnredlist.org/species/210364856/210364962
- https://www.lemurfaction.com/goodmans-mouse-lemur/
- https://primate.wisc.edu/primate-info-net/pin-factsheets/pin-factsheet-mouse-lemur/
Written by Sienna Weinstein, September 2024