The mouse lemurs are

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

lemur Lemurs ( ; from Latin ) are Strepsirrhini, wet-nosed primates of the Superfamily (biology), superfamily Lemuroidea ( ), divided into 8 Family (biology), families and consisting of 15 genera and around 100 existing species. They are Endemism, ...

s of the genus ''Microcebus''. Like all lemurs, mouse lemurs are native to

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. Mouse lemurs have a combined head, body and tail length of and weigh , 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 18–11 million years ago. Mouse lemurs are

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

; their diets are diverse and include

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

secretions,

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s, small

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s, gum,

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

, and also leaves and

bud In botany, a bud is an undeveloped or Plant embryogenesis, embryonic Shoot (botany), shoot and normally occurs in the axil of a leaf or at the tip of a Plant stem, stem. Once formed, a bud may remain for some time in a dormancy, dormant conditi ...

s depending on the season. Mouse lemurs are considered

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

—with very little morphological differences between the various species, but with high genetic diversity. Recent evidence points to differences in their mating calls, which are very diverse. Since mouse lemurs are nocturnal, they might not have evolved to look different, but have evolved various auditory and vocal systems. Mouse lemur brains can weigh less than while their

testes A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The ...

can weigh . 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 A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...

for human medical research.

Reproduction and evolution

Mouse lemurs are also known for their

sperm competition Sperm competition is the competitive process between Spermatozoon, spermatozoa of two or more different males to fertility, fertilize the same Egg cell, egg during sexual reproduction. Competition can occur when females have multiple potential m ...

. During breeding seasons, the testicles of male mouse lemurs increase in size to about 130% of their normal size. This was speculated to increase the sperm production thereby conferring an advantage for the individual to bear more offspring. There are various hypotheses relating the rapid evolution of mouse lemur species to this sperm competition. In sexually inactive females the vulva is sealed, during the reproductive cycle the vulva is open. The vaginal morphology is also based on the time of day. Analysis of the genomes of five different mouse lemur species revealed that Madagascar's biogeography had been undergoing change before the arrival of humans.

Species

* Genus ''Microcebus'': mouse lemurs ** Arnhold's mouse lemur, ''M. arnholdi'' ** Madame Berthe's mouse lemur, ''M. berthae'' ** Bongolava mouse lemur ''M. bongolavensis'' ** Boraha mouse lemur ''M. boraha'' ** Danfoss' mouse lemur ''M. danfossi'' ** Ganzhorn's mouse lemur. ''M. ganzhorni'' ** Gerp's mouse lemur. ''M. gerpi'' ** Reddish-gray mouse lemur, ''M. griseorufus'' ** Jolly's mouse lemur, ''M. jollyae'' ** Jonah's mouse lemur, ''M. jonahi'' ** Goodman's mouse lemur, ''M. lehilahytsara'' ** MacArthur's mouse lemur, ''M. macarthurii'' ** Claire's mouse lemur, ''M. mamiratra'', synonymous to ''M. lokobensis'' ** Bemanasy mouse lemur, ''M. manitatra'' ** Margot Marsh's mouse lemur, ''M. margotmarshae'' ** Marohita mouse lemur, ''M. marohita'' ** Mittermeier's mouse lemur, ''M. mittermeieri'' ** Gray mouse lemur, ''M. murinus'' ** Pygmy mouse lemur, ''M. myoxinus'' ** Golden-brown mouse lemur, ''M. ravelobensis'' ** Brown mouse lemur, ''M. rufus'' ** Sambirano mouse lemur, ''M. sambiranensis'' ** Simmons' mouse lemur, ''M. simmonsi'' ** Anosy mouse lemur. ''M. tanosi'' ** Northern rufous mouse lemur, ''M. tavaratra''

References

External links

*
Mouse lemur skeleton
– Skeleton from the University of Texas at Austin
BBC video clips and news articles
{{Taxonbar, from=Q4377 Taxa named by Étienne Geoffroy Saint-Hilaire