Microcebus murinus

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. The gray or lesser mouse lemur is named for its brownish-gray fur and mouse-like size and appearance. The genus name, Microcebus, derives from the Greek words mikros, meaning 'small', and kebos, meaning 'monkey'. The Latin version of kebos, cebus, is a common suffix used for primate names, despite the fact that the gray mouse lemur is a lemur, and not a monkey. The species name, murinus, means 'mouse-like' and derives from the Latin word mus, or 'mouse', and the Latin suffix -inus, which means 'like'. The lemur is known locally by several names in Malagasy, depending upon the region. Around Tôlanaro (Fort Dauphin), it is called pondiky . In the northern end of its range, it is known as tsidy . Around Morondava, it is referred to as koitsiky , titilivaha , and vakiandry . In many cases, these Malagasy names are also used for other visually indistinguishable mouse lemur species that live within its range. As its name implies, the gray mouse lemur is a lemur, a type of primate, and belongs to the suborder Strepsirrhini and infraorder Lemuriformes. Within Lemuriformes, it belongs to the family Cheirogaleidae, which contains the mouse lemurs, dwarf lemurs, giant mouse lemurs, fork-marked lemurs, and hairy-eared dwarf lemur. The mouse lemur genus Microcebus includes the smallest primates in the world. Phylogenetic analyses of D-loop DNA sequences of various lemur species suggest that the gray mouse lemur may be most closely related to the reddish-gray mouse lemur (M. griseorufus). First described in 1777 by English illustrator John Frederick Miller, M. murinus remained the only species of its genus, as well as the name used for all mouse lemurs on Madagascar, between the first major taxonomic revision in 1931 and an extensive field study conducted in 1972. The field study distinguished the brown mouse lemur, M. rufus—then considered a subspecies—as a distinct, sympatric species in the southeastern part of the island. Upon this revision, the gray mouse lemur was thought to account for all mouse lemurs that lived in the drier parts of the north, west, and south, while the brown mouse lemur represented the eastern rainforest mouse lemurs. More recently, scientific understanding of the distribution and diversity of the mouse lemurs has become much more complex. Additional field studies, genetic testing, and resulting taxonomic revisions throughout the 1990s and 2000s identified numerous new mouse lemur species, demonstrating that the genus includes at least 17 cryptic species. The gray mouse lemur shares many traits with other mouse lemurs, including soft fur, a long tail, long hind limbs, a dorsal stripe down the back (not always distinct), a short snout, rounded skull, prominent eyes, and large, membranous, protruding ears. It has large eyes and a tapetum lucidum to enhance its vision at night. The dorsal coat is brownish-gray with various reddish tones, the flanks are light gray to beige, and the ventral fur has discrete dull beige or whitish-beige patches along portions of the belly. On the rounded face, there is a pale white patch above the nose and between the eyes; some individuals have dark orbital markings. The furred portions of the hands and feet are off-white.