Is Madame Berthe's Mouse lemur extinct?

In search for Mme. Berthe's mouse lemur, a species on the brink of extinction in the Central Menabe region, Western Madagascar

Available data from the Aire Protégée Menabe Antimena (APMA) in the Central Menabe region of western Madagascar suggest that the already critically endangered Madame Berthe's mouse lemur (Microcebus berthae) may be on the verge of extinction. We have classified M. berthae as critically endangered (CR) on the IUCN Red List, and the species continues to be listed by the SSC Primate Specialist Group as one of the 25 most endangered primates.

The range of the world's smallest primate is limited to the deciduous dry forests of the Menabe Central region. Despite formal protection by the Aire Protégée Menabe Antimena (APMA) since 2015, its remaining potential habitat continues to shrink. Formerly stable populations in the Kirindy Forest have not been detected since 2020, and there are no captive populations.

In the first phase of the project (2022-2023), we systematically surveyed all remaining forests within the Mme. Berthes mouse lemur's range and were able to rediscover at least one remnant population. During our nightly transect surveys and trapping activities, we also collected information on the occurrence of sympatric, nocturnal lemur species, the gray mouse lemur (Microcebus murinus), the fat-tailed dwarf lemur (Cheirogaleus medius), the giant mouse lemur (Mirza coquereli), the fork-marked lemur (Phaner pallescens), and the red-tailed sportive lemur (Lepilemur ruficaudatus). Some of those species have been shown in our earlier studies to determine the distribution of M. berthae. In order to better understand the observed and sometimes unexpected distribution patterns, we initiated a follow-up project in 2023 (see “What is causing the disappearance of Mme. Berthe's mouse lemur from the dry deciduous forests of western Madagascar?”).