Lemur in the context of Algeripithecus

A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (/məˈmeɪli.ə/). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy.

The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, bovids and whales), and the Carnivora (including cats, dogs, and seals).

Strepsirrhini or Strepsirhini (/ˌstrɛpsəˈraɪni/ ; STREP-sə-RY-nee) is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and Southeast Asia. Collectively they are referred to as strepsirrhines.

Also belonging to the suborder are the extinct adapiform primates, which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.

A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints extremely similar to human fingerprints) are often described as having "hands" instead of paws on their front limbs. The raccoon is usually described as having "hands" though opposable thumbs are lacking.

Some evolutionary anatomists use the term hand to refer to the appendage of digits on the forelimb more generally—for example, in the context of whether the three digits of the bird hand involved the same homologous loss of two digits as in the dinosaur hand.

The composition of Madagascar's wildlife reflects the fact that the island has been isolated for about 88 million years. The prehistoric breakup of the supercontinent Gondwana separated the Madagascar-Antarctica-India landmass from the Africa-South America landmass around 135 million years ago. Madagascar later split from India about 88 million years ago, allowing plants and animals on the island to evolve in relative isolation.

As a result of the island's long isolation from neighboring continents, Madagascar is home to an abundance of plants and animals found nowhere else on Earth. Approximately 90 percent of all plant and animal species found in Madagascar are endemic, including the lemurs (a type of strepsirrhine primate), the carnivorous fossa and many birds. This distinctive ecology has led some ecologists to refer to Madagascar as the "eighth continent", and the island has been classified by Conservation International as a biodiversity hotspot. As recent as 2021, the "smallest reptile on earth" was also found in Madagascar, Brookesia nana, also known as the nano-chameleon.

A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains.

Insects are the major pollinators of most plants, and insect pollinators include all families of bees and most families of aculeate wasps; ants; many families of flies; many lepidopterans (both butterflies and moths); and many families of beetles. Vertebrates, mainly bats and birds, but also some non-bat mammals (monkeys, lemurs, possums, rodents) and some lizards pollinate certain plants. Among the pollinating birds are hummingbirds, honeyeaters and sunbirds with long beaks; they pollinate a number of deep-throated flowers. Humans may also carry out artificial pollination.

Lemuriformes is the sole extant infraorder of primate that falls under the suborder Strepsirrhini. It includes the lemurs of Madagascar, as well as the galagos and lorisids of Africa and Asia, although a popular alternative taxonomy places the lorisoids in their own infraorder, Lorisiformes.

Lemuriform primates are characterized by a toothcomb, a specialized set of teeth in the front, lower part of the mouth mostly used for combing fur during grooming.

Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass (now Europe, Asia and North America), reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the Miocene epoch. Some adapiforms resembled living lemurs.

Adapiforms are known from the fossil record only, and it is unclear whether they form a monophyletic or paraphyletic group. When assumed to be a clade, they are usually grouped under the "wet-nosed" taxon Strepsirrhini, which would make them more closely related to the lemurs and less so to the "dry-nosed" Haplorhini taxon that includes monkeys and apes.

Lemurs, primates belonging to the suborder Strepsirrhini which branched off from other primates less than 63 million years ago, evolved on the island of Madagascar, for at least 40 million years. They share some traits with the most basal primates, and thus are often confused as being ancestral to modern monkeys, apes, and humans. Instead, they merely resemble ancestral primates.

Lemurs are thought to have evolved during the Eocene or earlier, sharing a closest common ancestor with lorises, pottos, and galagos (lorisoids). Fossils from Africa and some tests of nuclear DNA suggest that lemurs made their way to Madagascar between 40 and 52 mya. Other mitochondrial and nuclear DNA sequence comparisons offer an alternative date range of 62 to 65 mya. An ancestral lemur population is thought to have inadvertently rafted to the island on a floating mat of vegetation, although hypotheses for land bridges and island hopping have also been proposed. The timing and number of hypothesized colonizations has traditionally hinged on the phylogenetic affinities of the aye-aye, the most basal member of the lemur clade.

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 20–30 centimetres (7.9–11.8 in) and weigh 30–65 grams (1.1–2.3 oz), 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. They can live for about 18 years in captivity. Gestation is about 2 months. The total population for mouse lemurs isn't yet known.

The evolutionary history of the primates can be traced back 57-90 million years. One of the oldest known primate-like mammal species, Plesiadapis, came from North America; another, Archicebus, came from China. Other such early primates include Altiatlasius and Algeripithecus, which were found in Northern Africa. Other similar basal primates were widespread in Eurasia and Africa during the tropical conditions of the Paleocene and Eocene.Purgatorius is the genus of the four extinct species believed to be among the earliest example of a primate or a proto-primate, a primatomorph precursor to the Plesiadapiformes, dating to as old as 66 million years ago.

The surviving tropical population of primates, which is seen most completely in the upper Eocene and lowermost Oligocene fossil beds of the Faiyum depression southwest of Cairo, gave rise to all living species—lemurs of Madagascar, lorises of Southeast Asia, galagos or "bush babies" of Africa, and the anthropoids: platyrrhine or New World monkeys, catarrhines or Old World monkeys, and the apes, including Homo sapiens.

Prosimians are a group of primates that includes all living and extinct strepsirrhines (lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the simians. They are considered to have characteristics that are more "primitive" (ancestral or plesiomorphic) than those of simians (monkeys, apes, and humans).

Simians emerged within the Prosimians as sister group of the haplorhine tarsiers, and therefore cladistically belong to this group. Simians are thus distinctly closer related to tarsiers than lemurs are. Strepsirrhines bifurcated some 20 million years earlier than the tarsier–simian bifurcation. However, simians are traditionally excluded, rendering prosimians paraphyletic. Consequently, the term "prosimian" is no longer widely used in a taxonomic sense, but is still used to illustrate the behavioral ecology of tarsiers relative to the other primates.

Cathemerality, sometimes called metaturnality, is an organismal activity pattern of irregular intervals during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood are undertaken. This activity differs from the generally monophasic pattern (sleeping once per day) of nocturnal and diurnal species as it is polyphasic (sleeping 4-6 times per day) and is approximately evenly distributed throughout the 24-hour cycle.

Many animals do not fit the traditional definitions of being strictly nocturnal, diurnal, or crepuscular, often driven by factors that include the availability of food, predation pressure, and variable ambient temperature. Although cathemerality is not as widely observed in individual species as diurnality or nocturnality, this activity pattern is seen across the mammal taxa, such as in lions, coyotes, and lemurs.

The ring-tailed lemur (Lemur catta) is a medium- to larger-sized strepsirrhine (wet-nosed) primate and the most internationally recognized lemur species, owing to its long, black-and-white, ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the Lemur genus. Like all lemurs, it is endemic to the island of Madagascar, where it is endangered. Known locally in Malagasy as maky ([makʲ] , spelled maki in French) or hira, it ranges from gallery forests to spiny scrub in the southern regions of the island. It is omnivorous, as well as the most adapted to living terrestrially of the extant lemurs.

The ring-tailed lemur is highly social, living in groups—known as "troops"—of up to 30 individuals. It is also a female-dominant species, a commonality among lemurs. To keep warm and reaffirm social bonds, groups will huddle together. Mutual grooming is another vital aspect of lemur socialization (as with all primates), reaffirming social and familial connections, while also helping rid each other of any potential insects. Ring-tailed lemurs are strictly diurnal, being active exclusively during daylight hours. Due to this lifestyle, they also sunbathe; the lemurs can be observed sitting upright on their tails, exposing their soft, white belly fur towards the sun. They will often also have their palms open and eyes gently closed. Like other lemurs, this species relies strongly on their sense of smell, and territorial marking, with scent glands, provides communication signals throughout a group's home range. The glands are located near the eyes, as well as near the anus. The males perform a unique scent-marking behavior called spur-marking and will participate in stink fights by dousing their tails with their pheromones and "wafting" them at opponents. Additionally, lemurs of both sexes will scent-mark trees, logs, rocks or other objects by simply rubbing their faces and bodies onto it, not unlike a domestic cat.

Palaeopropithecus is a recently extinct genus of large sloth lemurs from Madagascar related to living lemur species found there today. Three species are known, Palaeopropithecus ingens, P. maximus, and P. kelyus. Radiocarbon dates indicate that they may have survived until around 1300–1620 CE. Malagasy legends of the tretretretre or tratratratra are thought to refer to P. ingens.

Evidence suggests a solely arboreal lifestyle with frequent upside down suspension, hence the name sloth lemur.