Tavaratra Mouse Lemur, Microcebus tavaratra
TAVARATRA MOUSE LEMUR
Microcebus tavaratra
Geographic Distribution and Habitat
The Tavaratra mouse lemur, also called the northern rufous mouse lemur, is found only in northern Madagascar. They make their home in dry deciduous forests that lose their leaves seasonally), in the limited vegetation of savannah and scrubland, and in the gallery forests connecting these open landscapes to rivers and wetlands. The Tavaratra mouse lemur has even been found in the canyons of the limestone needles formed within Ankarana National Park. They have also been found in human-modified habitats, such as fragmented forests that have been separated by human development or in vanilla plantations. The total range the Tavaratra mouse lemur is believed to occur in is estimated to be 2,942 sq miles (7,620 sq km).
Size, Weight, and Lifespan
The only reference for the size of the Tavaratra mouse lemur we currently have comes from a single female, with a head-body length of 5.12 inches (130 mm), a tail length of 6.02 inches (153 mm), and a weight of 0.17 pounds (78 g). While having only a single individual to refer to makes it difficult to know how well these represent the species as a whole, it still gives us some idea of how the Tavaratra mouse lemur compares to other mouse lemurs. The measurements from this individual indicate that the Tavaratra mouse lemur may be on the relatively larger side for mouse lemurs.
Currently, the lifespan of the Tavaratra mouse lemur is unknown.
Appearance
As suggested by their name, the Tavaratra mouse lemur has a very mouse-like appearance with their small size and large ears. Their eyes are also very large and take up most of their face. Their fur is dark brown and characterized by a middorsal line down the middle of the back extending to the base of the tail. The middorsal line may vary in starting point, whether it starts at the top of the head or the shoulders.
Diet
The specific diet of the Tavaratra mouse lemur is unknown, but likely similar to other mouse lemurs. They are likely omnivorous and mostly sustain themselves on fruits and insects. Their diet may also expand to flowers and nectar, leaves, and sap from trees which has proven to be an important food source for many mouse lemurs.
Behavior and Lifestyle
Because many species of mouse lemur we know today, including the Tavaratra mouse lemur, are relatively newly recognized as their own species, not much is known about their specific behaviors that may differ from other species. However, we can still draw on what is known about other mouse lemur species to gain some insight into the Tavaratra mouse lemur’s lifestyle.
Tavaratra mouse lemurs are nocturnal, meaning they are active throughout the night and asleep during the day. Their large eyes allow them to pick up as much of the minimal light in the nighttime as possible. They are arboreal quadrupeds, moving through the trees on all fours. Living in dry habitats, resources can sometimes be scarce. Similar to many mouse lemurs, Tavaratra mouse lemurs may store fat in their tails as an energy reserve for when they enter torpor when their metabolism drops to the bare minimum. This adaptation allows mouse lemurs to survive through periods where resources may not be abundantly available, by entering what is essentially an “energy-saver” mode. Some species of mouse lemur will enter daily torpor, while others do so seasonally. Currently, it’s not clear which strategy the Tavaratra mouse lemur may follow.
The name “Tavaratra” is derived from the Malagasy language meaning “from the north”.
Due to a lack of research, the daily (or nightly) life of the Tavaratra mouse lemur is largely unknown. We can, however, look to other mouse lemurs for a general idea of what their group dynamics look like. Mouse lemurs are typically known to live in multi-male multi-female dispersed social groups. This means that, while the individuals in the group may share or overlap in a home range, they are often not found together within their shared range. Typically, females will sleep together in a group with other related females and socialize together, while males typically sleep alone. Males will have larger home ranges than females and may overlap in range with multiple groups of females. Females tend to be more dominant than males and will have greater access to food, which benefits their health for pregnancy, milk production, and childcare.
As with much of their behavior, communication in the Tavaratra mouse lemur is largely unknown. However, we can use when we know about their appearance, as well as the communication of other mouse lemurs, to get an idea of how they “speak” with each other. Because individuals are often largely spaced apart, their big ears allow them to pick up each others’ calls from far away. Mostly, these calls alert other mouse lemurs of a potential danger, or to advertise their potential as a mate. Scent marking also serves as an advertisement to the opposite sex, and is done by rubbing urine on branches (also called urine washing). Scent marking also allows males to mark their territory and warn other nearby males to stay away.
Like other prosimian primates like lemurs, galagos, and lorises, mouse lemurs do not engage in reproductive behavior year-round. Their reproductive behaviors are restricted to seasonal estrus. Based on what is known for closely related mouse lemur species, many studies consider female Tavaratra mouse lemurs to be of reproductive age as of their first year, and gestation (pregnancy) is likely around two months. They may give birth to one to three infants at a time. While mom forages for food, she’ll often leave her babies in a nearby tree hole or nook.
The specific ecological role of the Tavaratra mouse lemur has not been described, but this does not mean they should be assumed unimportant. Because they do consume fruit, we can assume that they likely act as seed dispersers and play an important role in maintaining the biodiversity of the forests they live in.
The Tavaratra mouse lemur is classified as Vulnerable by the International Union for Conservation of Nature (IUCN, 2018), appearing on the IUCN Red List of Threatened Species. Their environment is at threat of degradation by slash-and-burn methods of clearing farmland for cattle pastures and crop production. Scientists also predict that the dry forests of Madagascar, such as those the Tavaratra mouse lemur inhabits, will be negatively impacted by the continued threat of climate change. With these threats, the population of the Tavaratra mouse lemur is predicted to decrease.
Tavaratra mouse lemurs are listed in Appendix II 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.
Researchers have noticed several species of mouse lemur, including the Tavaratra mouse lemur, living in vanilla plantations, which may serve as a means of maintaining connections between fragmented forests. Vanilla is one of Madagascar’s top exports (although the plant itself is native to Mexico), and is farmed in either large industrial plantations or in small-scale plantations that utilize existing forests to support the growth of vanilla orchids. Although not as ideal as natural forests, scientists believe these small-scale plantations may play an important role in lemur conservation. Not only do they provide suitable habitat, but due to the high value of vanilla, these forest plantations are less likely to be converted into more traditional farmland, and ultimately reduce the risk of habitat loss.
- https://www.iucnredlist.org/species/41571/115579176
- https://cites.org/eng/app/appendices.php
- Rasolooarison, R. M., Goodman, S. M., & Ganzhorn, J. U. (2000). Taxonomic revision of mouse lemurs (Microcebus) in the western portions of Madagascar. International Journal of Primatology, 21, 963-1019.
- Sgarlata, G. M., Salmona, J., Aleixo-Pais, I., Rakotonanahary, A., Sousa, A. P., Kun-Rodrigues, C., … & Chikhi, L. (2018). Genetic differentiation and demographic history of the northern rufous mouse lemur (Microcebus tavaratra) across a fragmented landscape in northern Madagascar. International Journal of Primatology, 39, 65-89.
- Hending, D., Andrianiaina, A., Rakotomalala, Z., & Cotton, S. (2018). The use of vanilla plantations by lemurs: encouraging findings for both lemur conservation and sustainable agroforestry in the Sava Region, Northeast Madagascar. International Journal of Primatology, 39, 141-153.
- Gould, L., Sauther, M., and Cameron, A. (2011). Lemuriformes. In Primates in Perspective (second, pp. 76–77). Oxford University.
- Hending, D., Holderied, M., McCabe, G., & Cotton, S. (2022). Effects of future climate change on the forests of Madagascar. Ecosphere, 13(4), e4017.
Written by Lina Rademacher, November 2024