Some species are generally found in monogamous family groups (Cheirogaleus, Phaner, Mirza). Microcebus species occur in multi-male, multi-female social groups in which males pursue females when they are in estrous. Males use mating calls during the time of breeding. Females can have multiple male mates and give birth to litters with multiple paternity as a result. Females have distinct estrous cycles. In some species the vagina is sealed with a membrane when the female is not in estrous. A vaginal plug forms after copulation in some species. Estrous is signaled by swelling of the vulva.
Mating System: monogamous ; polygynandrous (promiscuous)
Dwarf and mouse lemurs breed seasonally, generally during the wet season from October to March. Smaller species can have multiple litters in a year, each with 2 to 3 young, larger species give birth to single offspring. Gestation is from 2 to 3 months and the young are cared for in a nest.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Females nurse their young regularly throughout the day, making it necessary for them to return to the nest throughout their nighttime foraging period.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
There are no Cheirogaleidae fossils, although they are known from subfossil deposits on Madagascar. An Eocene fossil genus from Pakistan, Bugtilemur, is considered part of Cheirogaleidae.
Individuals in social groups communicate with each other through scent marking and vocalizations. Scent marking involves leaving urine, feces, and gland secretions on trees and branches. Vocalizations include contact calls, alarm calls, and territorial defense calls, most are relatively high pitched sounds.
Communication Channels: acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Most dwarf and mouse lemur species are considered "data deficient" by the IUCN, primarily because many species are newly named and poorly understood. Of the 29 species recognized by the IUCN, 14 species are data deficient, 7 are least concern, 1 is near threatened, 2 are vulnerable, and 4 are endangered. Species considered least concern are still considered potentially vulnerable to habitat destruction and populations are thought to be in decline. Smaller species tend to be more common and widespread, larger species tend to have fragmentary distributions and are less common, therefore more threatened. Previously, all lemurs were considered endangered, so they are all listed on Appendix I of CITES.
Hairy-eared dwarf lemurs (Allocebus trichotis) were considered extinct until they were rediscovered in 1989.
There are 21 species in 5 genera in the family Cheirogaleidae. As with most Malagasy mammals, recent research has resulted in the naming of several new species in recent years. These are the smallest lemur species and are all arboreal, nocturnal, and social. They are all similar in ecology, with relatively restricted ranges and some variation in diets.
There are no adverse effects of dwarf and mouse lemurs on humans.
Dwarf and mouse lemurs are too small to be hunted for food to a great extent. They may help to disperse seeds in forests and control insect pests to some extent.
Positive Impacts: controls pest population
Through their frugivory, cheirogaleids may help to disperse seeds. They also impact insect populations through predation.
Ecosystem Impact: disperses seeds
Dwarf and mouse lemurs are generally omnivorous, eating fruits, insects, nectars, plant gums, and occasionally leaves and small vertebrates. Some species specialize on portions of that diet. For example, Cheirogaleus species eat mainly fruit and Phaner species specialize on plant gums and have a well-developed tooth comb in the lower jaw for this purpose. Most species forage mainly on the small branches of trees and shrubs below 10 m high, but they also forage on tree trunks, especially Phaner species, which have sharp claws on their digits to allow clinging to vertical surfaces. Phaner species also have an enlarged caecum to help them digest plant gums.
Primary Diet: omnivore
Dwarf and mouse lemurs are restricted to forested regions of Madagascar.
Biogeographic Regions: ethiopian (Native )
Other Geographic Terms: island endemic
Dwarf and mouse lemurs are found in forested habitats of different types, including evergreen, deciduous, and scrub forests. Mouse lemurs (Microcebus) are also found in suburban and agricultural areas. Dwarf and mouse lemurs rest during the day in tree hollows or rounded leaf nests in Microcebus and Mirza species.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest ; scrub forest
Other Habitat Features: suburban ; agricultural ; riparian
Dwarf lemurs (Cheirogaleus) have been recorded living up to 23.2 years old and fork-marked lemurs (Phaner furcifer) have been recorded living up to 25 years in captivity. Longevity in the wild has not been well documented and is likely to be shorter than captive lifespans.
Dwarf and mouse lemurs are the smallest lemurs, from 12 to 27 cm in length and 30 (Microcebus berthae) to 460 g (Phaner furcifer). Pygmy, or Berthe's, mouse lemurs (Microcebus berthae) are the smallest primates. Cheirogaleids have gray or brown dorsal pelage and lighter, creamy or yellowish pelage on their ventral surfaces. Some species have bold markings on their faces, such as eye rings or nose stripes. The fur is often thick and woolly. In general species in eastern Madagascar (more mesic forests) have reddish or brown fur and species in western Madagascar (more arid forests) have grayish fur. Dwarf and mouse lemurs are characterized by unusually long tails, ranging from about the length of the body to roughly half again as long; large, thin, and membranous ears; and well developed facial and carpal vibrissae. They have large, forward-facing eyes, reflecting their nocturnal lifestyle, compact bodies, and long, delicate fingers with rounded tips. In many species males are slightly larger than females.
Their hind feet have elongated calcaneus and navicular bones. As with other strepsirhines, they have a distinctive " toilet claw" on the second digit of their hind feet. Their thumb (pollex) is not as conspicuously separated from the other digits as in lemurs; and the third and fourth digits of both feet are similar in length.
Cranially, dwarf and mouse lemurs are defined by details of their cranial circulation and bullae. The frontal and palatal bones contact the orbit in most cheirogaleids. They have the typical strepsirhine tooth comb made up of lower incisors and canines, and their dental formula is 2/2, 1/1, 3/3, 3/3 = 36. In contrast to lemurs, their upper incisors are elongate. Hypocones are small are absent on the upper molars.
Other Physical Features: endothermic ; heterothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger
Predators of cheirogaleids are not reported in the literature, but are likely to include nocturnal predators, such as snakes (Serpentes), owls (Strigiformes), and fossas (Cryptoprocta ferox). They are nocturnal, cryptically colored, arboreal, and agile, all helping to decrease their vulnerability to predators.
Anti-predator Adaptations: cryptic
Cheirogaleidae is a primate family including five genera and at least 30 species to date (Mittermeier et al., 2008) including the mouse lemurs, the dwarf lemurs, the fork-marked lemurs. Species in this family are all nocturnal and move quadrupedally with elongated bodies and short legs. Some cheirogaleids undergo periods of seasonal torpor (hibernation). This family contains what is likely the world’s smallest primate, the Madame Berthe’s Mouse Lemur (Microcebus berthae) (Mittermeier et al., 2006).
Cheirogaleids are smaller than the other lemurs and, in fact, they are the smallest primates. They have soft, long fur, colored grey-brown to reddish on top, with a generally brighter underbelly. Typically, they have small ears, large, close-set eyes, and long hind legs. Like all strepsirrhines, they have fine claws at the second toe of the hind legs. They grow to a size of only 13 to 28 cm, with a tail that is very long, sometimes up to one and a half times as long as the body. They weigh no more than 500 grams, with some species weighing as little as 60 grams.
Dwarf and mouse lemurs are nocturnal and arboreal. They are excellent climbers and can also jump far, using their long tails for balance. When on the ground (a rare occurrence), they move by hopping on their hind legs. They spend the day in tree hollows or leaf nests. Cheirogaleids are typically solitary, but sometimes live together in pairs.
Their eyes possess a tapetum lucidum, a light-reflecting layer that improves their night vision. Some species, such as the lesser dwarf lemur, store fat at the hind legs and the base of the tail, and hibernate. Unlike lemurids, they have long upper incisors, although they do have the comb-like teeth typical of all strepsirhines. They have the dental formula: 188.8.131.52.1.3.3
The females usually have three pairs of nipples. After a meager 60-day gestation, they will bear two to four (usually two or three) young. After five to six weeks, the young are weaned and become fully mature near the end of their first year or sometime in their second year, depending on the species. In human care, they can live for up to 15 years, although their life expectancy in the wild is probably significantly shorter.