Lepilemur septentrionalis is listed as Critically Endangered (CR) on the IUCN Red List (2008). Its population is unknown, but likely to be extremely small. The principal threats are habitat destruction for Eucalyptus plantations, collection of firewood, and charcoal production, and perhaps also hunting for food. Most of its habitat is already gone, and it does not occur in any official protected areas. What is more, it is uncertain whether any of the forest patches in which it still survives would be of sufficient size to warrant creation of a protected area. It was listed as one of the world’s 25 Most endangered primates in 2008 (Ravaorimanana et al., 2009). Total numbers are unknown but, taking into account its limited distribution in the forests of Sahafary, Andrahona and Andranomadiro, probably only about 100-150 individuals remain. Surveys of five areas in 2007 provided the following population estimates: 1) Area of Andrahona (forest patches and gallery forests of Andrahona, Analajanana, and Analanjavavy)—20 individuals in the entire area; 2) Area of Ankarakataova (forests of Ankarakataova Be and Ankarakataova kely)—none found; and 3) Area of Sahafary (degraded forest patches in Western Sahafary, Sahafary East, Sahafary North, Andravina, Sahandrano, Andranomadiro, and Analalava)—about 100 individuals (Ravaorimanana et al., 2009). None of these areas are protected. The combination of a very small range containing little and rapidly decreasing suitable habitat with high pressure from hunting makes this species especially threatened. A consortium of the Association Européenne pour l’Etude et la Conservation des Lémuriens (AEECL), the University Louis Pasteur of Strasbourg and the Fondation Nature et Decouverte supported the field work and the genetic study. Socio-economic studies are under way to determine the anthropogenic effect on the remaining population (Lernould, 2006). The Andrahona Forest is considered a sacred forest, but it is tiny. Furthermore, during a recent visit (R. A. Mittermeier, pers. obs., August, 2005), it was found to be riddled with trails and in the process of being exploited for saplings for local construction. During a later visit, E. E. Louis Jr. and colleagues located eight animals, but again in very degraded habitat measuring only 400 m × 20 m in size. This is clearly a species on the verge of extinction, and in need of special attention. This could include a last-ditch effort to save a piece of remaining habitat, with the Andrahona Forest perhaps presenting the best opportunity. Another option may be to undertake a captive breeding program, although members of the genus Lepilemur have always proven difficult to keep in zoos. As indicated above, it is possible that the sportive lemur in Montagne des Français, a calcareous massif 12 km from Antsiranana (= Diego-Suarez), is L. septentrionalis (D’Cruze et al., 2007; Sabel et al., 2009). A survey and genetic study is urgently needed to determine if the species occurring there is in fact L. septentrionalis, and not the more wide-ranging L. ankaranensis. If it is, then the prospects for survival of L. septentrionalis in the wild would be considerably improved. As of 2010, this species was not being kept in captivity (I. J. Porton, pers. comm.).
