The mouse lemurs are nocturnal lemurs of the genus Microcebus. Like all lemurs, mouse lemurs are native to Madagascar.

Mouse lemurs have a combined head, body and tail length of less than 27 centimetres (11 in), making them the smallest primates (the smallest species being Madame Berthe's mouse lemur); however, their weight fluctuates in response to daylight duration. Lemurs and mouse lemurs were announced by the IUCN as the most endangered of all vertebrates. There were two known mouse lemur species in 1992; by 2016, there were 24. It was estimated that the 24 mouse lemur species evolved from a common ancestor 10 million years ago. Evolution of mouse lemurs is an example for adaptive radiation.

Mouse lemurs are omnivorous; their diets are diverse and include insect secretions, arthropods, small vertebrates, gum, fruit, flowers, nectar, and also leaves and buds depending on the season.

Mouse lemurs are considered cryptic species—with very little morphological differences between the various species, but with high genetic diversity. Recent evidence points to differences in their mating calls, which is very diverse. Since mouse lemurs are nocturnal, they might not have evolved to look differently, but had evolved various auditory and vocal systems.

Mouse lemurs have the smallest known brain of any primate, at just 0.004 pound (2 grams).

As written in Genetics, mouse lemurs help to provide a more extensive understanding of the biology, behavior, and health of primates. Mouse lemurs are categorized as prosimian primates. They are among the smallest and most rapidly developing primates and are becoming more abundant in Madagascar and around the world. These tiny creatures are helping to prove valuable information about the biology and evolution of primates through the analysis of their phenotypes and mutations, especially as a model organism for human medical research.

In this page:

• Tavaratra Mouse Lemur (Microcebus tavaratra)

• Brown Mouse Lemur (Microcebus rufus)

• Grey Mouse Lemur (Microcebus murinus)

• Gray-brown Mouse Lemur (Microcebus griseorufus)

• Madame Berthe’s Mouse Lemur (Microcebus berthae)

Madame Berthe's mouse lemur (Microcebus berthae) or Berthe's mouse lemur is the smallest of the mouse lemurs and the smallest primate in the world; the average body length is 9.2 cm (3.6 in) and seasonal weight is around 30 g (1.1 oz).[4] Microcebus berthae is one of many species of Malagasy lemurs that came about through extensive speciation, caused by unknown environmental mechanisms and conditions.

This primate is found chiefly in the Kirindy Forest in western Madagascar. After its discovery in 1992 in the dry deciduous forest of western Madagascar, it was initially thought to represent a rediscovery of M. myoxinus, but comparative morphometric and genetic studies revealed its status as a new species, M. berthae.

This lemur is named after the conservationist and primatologist Berthe Rakotosamimanana of Madagascar, who was the Secretary General of the Groupe d'Etudes et de Recherche des Primates (GERP) from its founding until her death in 2005.

Microcebus berthae has short, dense dorsal pelage that is bicolored cinnamon and yellow ochre. The middorsal stripe is tawny in color. The midventral area of this species is chamois in color while the flanks are a mixture of pale chamois and light pale neutral gray. The dorsal and ventral underfur is neutral blackish neutral gray in color. The tail has short hair that is tawny. The crown and ears are also tawny in color. The orbits are surrounded by a narrow dark band. The area between the eyes is cinnamon in color. The hands and feet are dull beige.

Madame Berthe's mouse lemur is known to live in Kirindy Forest in Madagascar. It is now likely extirpated from the Andranomena Special Reserve and the Analabe private reserve. Madame Berthe's mouse lemurs use the tangles of tree vines to sleep in. Because of its limited spread, it is thought that they are specialist creatures that will live only in that one specific environment. Another idea suggests that they most likely compete with the gray mouse lemur (M. murinus), chiefly for resources.

Because of the high rate of deforestation in the surrounding Menabe forests (52%) between 1985 and 2000, less than 22,000 hectares (54,000 acres) of inhabitable forests remained between Kirindy Park, the Tsiribihina River, and the Reserve. Given that this lemur occurs at 0.36 lemurs per ha, it is estimated that about 7,920 mouse lemurs were left in the area in the year 2000. With deforestation continuing to occur on the island nation, the species is listed as critically endangered, at best.

Madame Berthe’s Mouse Lemur (Microcebus berthae) - Kirindy National Park

The Reddish-gray mouse lemur (Microcebus griseorufus) also known as the gray-brown mouse lemur or rufous-gray mouse lemur, is found in Western Madagascar in the region around Beza Mahafaly Reserve, north to Lamboharana.

Microcebus griseorufus has a pelage color that is alternating light neutral gray, pale neutral gray, and light pale neutral gray dorsally and ventrally light grayish-white on the anterior two-thirds and bicolored light grayish-white and pale neutral gray on the posterior one-third. There is a cinnamon colored dorsal stripe running from the crown of the head or the shoulders to the end of the tail. The head of this species has a pale neutral gray spot above the nose, cinnamon around the eyes, a clay colored crown, and eras that are light neutral gray. The dorsal side of the tail is cinnamon colored while the ventral side is grayish-beige on the most distal two-thirds and cinnamon with faint brownish black streaks on the proximal one-third. The hands and feet are colored grayish-white and the vibrissae are dark in color. This species has a relatively robust sku

Gray-brown Mouse Lemur (Microcebus griseorufus) - Andohahela National Park

The gray mouse lemur (Microcebus murinus), grey mouse lemur or lesser mouse lemur, is a small lemur, a type of strepsirrhine primate, found only on the island of Madagascar. Weighing 58 to 67 grams (2.0 to 2.4 oz), it is the largest of the mouse lemurs (genus Microcebus), a group that includes the smallest primates in the world. The species is named for its mouse-like size and coloration and is known locally (in Malagasy) as tsidy, koitsiky, titilivaha, pondiky, and vakiandry. The gray mouse lemur and all other mouse lemurs are considered cryptic species, as they are nearly indistinguishable from each other by appearance. For this reason, the gray mouse lemur was considered the only mouse lemur species for decades until more recent studies began to distinguish between the species.

Like all mouse lemurs, this species is nocturnal and arboreal. It is very active, and though it forages alone, groups of males and females form sleeping groups and share tree holes during the day. It exhibits a form of dormancy called torpor during the cool, dry winter months, and in some cases undergoes seasonal torpor (or hibernation), which is unusual for primates. The gray mouse lemur can be found in several types of forest throughout western and southern Madagascar. Its diet consists primarily of fruit, insects, flowers, and nectar. In the wild, its natural predators include owls, snakes, and endemic mammalian predators. Predation pressure is higher for this species than among any other primate species, with one out of four individuals taken by a predator each year. This is counterbalanced by its high reproductive rate. Breeding is seasonal, and distinct vocalizations are used to prevent hybridization with species that overlap its range. Gestation lasts approximately 60 days, and typically two young are born. The offspring are usually independent in two months, and can reproduce after one year. The gray mouse lemur has a reproductive lifespan of five years, although captive individuals have been reported to live up to 15 years.

Although threatened by deforestation, habitat degradation, and live capture for the pet trade, it is considered one of Madagascar's most abundant small native mammals. It can tolerate moderate food shortages by experiencing daily torpor to conserve energy, but extended food shortages due to climate change may pose a significant risk to the species.

Grey Mouse Lemur (Microcebus murinus) - Kirindy National Park

The brown mouse lemur (Microcebus rufus) is a small primate, and like the other mouse lemurs can only be found on the island of Madagascar. They are known also as the rufous mouse lemur, eastern rufous mouse lemur, red mouse lemur, or russet mouse lemur. Its dorsal side is brown or reddish-brown, while ventrally it is a whitish-grey.

It was originally considered a subspecies of the gray mouse lemur (Microcebus murinus) until 1977, when it was reclassified as a separate species.

The mouse lemurs are among the shortest-lived of primates. The brown mouse lemur has a lifespan of 6–8 years in the wild, although it averages 12 years under human care.

It can be found in rainforests in Eastern Madagascar, and is widely distributed. It is a solitary and nocturnal creature. Brown mouse lemurs are mammals.

Brown Mouse Lemur (Microcebus rufus) - Mantadia National Park

The northern rufous mouse lemur (Microcebus tavaratra), northern brown mouse lemur, or Tavaratra mouse lemur is found in northern Madagascar from the Ankarana Special Reserve in the west to the Manambato River in the northeast, and up to the Irodo River in the north of the Analamerana Special Reserve. The complete distribution range of M. tavaratra is still to be defined as some areas surrounding the described distribution have not been visited yet. For example, M. tavaratra has been reported to possibly occur from the Irodo up to the Montagne des Français. Its known distribution cover four protected areas – the Ankarana Special Reserve, and the Analamerana Special Reserve both managed by Madagascar National Parks, the Loky-Manambato protected area (Daraina), and the Andavakoeira-Andrafiamena protected area, both Managed by the NGO Fanamby

Microcebus tavaratra has long, dense pelage that is bicolored to tricolored, raw umber, clay color, and yellow ochre, dorsally and a whitish-beige color ventrally. The middorsal stripe varies in color from raw umber to verona brown. The crown and ears of this species are a reddish shade and the area between the eyes is grayish-white. The orbital area is raw umber and cinnamon and around the anterior portion of the eyes there are black markings. The proximal part of the tail is bicolored raw umber and cinnamon, and the distal portion of the tail is cinnamon brown and raw umber. The pelage of the hands and feet of the northern rufous mouse lemur is whitish-gray in color. This species has vibrissae that are dark in color.

Tavaratra Mouse Lemur (Microcebus tavaratra) - Ankarana National Park