lemurs were not only large (and thus ideal prey species), but also slow-moving (and thus more vulnerable to human predation), their presumably slow-reproducing and low-density populations were least likely to survive the introduction of humans. Gradual changes in climate have also been blamed, and may have played a minor role; however since the largest lemurs also survived the climatic changes from previous ice ages and only disappeared following the arrival of humans, it is unlikely that climatic change was largely responsible. There is strong evidence of extensive declines in extant populations since the introductions of humans, particularly among the larger and more specialized lemurs. As long as habitats continue to shrink, degrade and fragment, extinctions are likely to continue. Taxonomic classification Lemurs are classified under eight families, three of which are extinct: Family: †Archaeolemuridae : monkey lemurs Genus: †Archaeolemur (2 extinct species) Genus: †Hadropithecus (1 extinct species) Family: Cheirogaleidae Genus: Allocebus: hairy-eared dwarf lemur (1 extant species) Genus: Cheirogaleus: dwarf lemurs (9 extant species) Genus: Microcebus: mouse lemurs (24 extant species) Genus: Mirza: giant mouse lemurs (2 extant species) Genus: Phaner: fork-marked lemurs (4 extant species) Family: Daubentoniidae: aye-aye Genus: Daubentonia (1 extant species, 1 extinct species) Family: Indriidae Genus: Avahi: woolly lemurs (9 extant species) Genus: Indri: indri (1 extant species) Genus: Propithecus: sifakas (9 extant species) Family: Lemuridae Genus: Eulemur: true lemurs (12 extant species) Genus: Hapalemur: bamboo lemurs (6 extant species, 3 extant subspecies) Genus: Lemur: ring-tailed lemur (1 extant species) Genus: †Pachylemur (2 extinct species) Genus: Varecia: ruffed lemurs (2 extant species, 3 extant subspecies) Family: Lepilemuridae: sportive lemurs Genus: Lepilemur (26 extant species) Family: †Megaladapidae: koala lemurs Genus: †Megaladapis (3 extinct species) Family: †Palaeopropithecidae: sloth lemurs Genus: †Archaeoindris (1 extinct species) Genus: †Babakotia (1 extinct species) Genus: †Mesopropithecus (3 extinct species) Genus: †Palaeopropithecus (3 extinct species) The placement of lemurs within the order Strepsirrhini is currently under debate, although both sides agree upon the same phylogenetic tree. Order Primates Suborder Strepsirrhini: lemurs, galagos, and lorisids Infraorder Lemuriformes Superfamily Lemuroidea Family †Archaeolemuridae Family Cheirogaleidae Family Daubentoniidae Family Indriidae Family Lemuridae Family Lepilemuridae Family †Megaladapidae Family †Palaeopropithecidae Superfamily Lorisoidea Suborder Haplorrhini: tarsiers, monkeys and apes Key Extant species All lemurs belong to the suborder Strepsirrhini within the order Primates. The 101 extant species and subspecies are divided among 5 families and 15 genera. They range in weight from (Madame Berthe's mouse lemur) to as much as (indri).