(Fischer, 1806 )

(Eng) Demidoff's dwarf bushbaby

(Fre) Galago de Demidoff

alago. demidoff (often listed as G. demidovii) does not include G. thomasi, which is acknowledge as a fully distinct species (Oates, 1996). Several forms of dwarf galago have recently been described in Tanzania and Malawi through vocalization studies; these so-called "Roller callers" have been provisionally grouped within G. demidoff, but further clarification is needed, since some of these appear to merit species status (Oates, 1996). As reported by Kingdon (1997) they might be classified as:

• Galagoides sp. nov. (named rondoensis by P. Honess, 1996), known to be present only on the Rondo plateau;
• Galagoides sp. nov. (named udzungwensis by P. Honess, 1996), which occurs below the Uzingwa Mts.;
• Galagoides sp. nov. (orinus, ?) from the Usambara Mts.

Not listed in the IUCN Red List Categories as a species, but Data Deficient (DD) in Tanzania for the three new discovered forms: G. orinus (Amani dwarf galago), G. rondoensis (Rondo dwarf galago), G. udzungwensis (Matundu galago).

The main aspects of the ecology of this species were investigated in Makoku (Gabon) by Charles-Dominique (1971, 1977, 1979). In Cameroon, Gartlan & Struhsaker (1979) focused on the niche separation with coexisting primates and interspecific relationships. A study on coexistence and interaction among primates was also carried out by Mitani (1991) in the Campo Animal Reserve (Cameroon). Effects of forest exploitation on the species’ density were investigated in the Kibale Forest (Uganda) by Weisenseel et al. (1993). Data on the species’ occurrence are available for Angola (Feiler, 1990), Bioko Island (Butynski & Koster, 1994), Gabon (Blom et al., 1992), Ghana (Booth, 1979), and Malawi (Courtenay & Bearder, 1989); most of the authors mentioned also give some information on the species’ ecology. Its presence on Mount Nimba (Liberia) is analysed by Coe (1975); the author includes a very detailed description of the area surveyed, supplying information on the habitat in which the species occurs there. General information on its ecology and distribution are reported by several authors (Bourlière, 1985; Eisenberg et al., 1979; Estes, 1991; Kingdon, 1971-77, 1997; Nash et al., 1989; Stuart & Stuart, 1997). Status and threats are discussed in Oates (1996) and Southwick et al. (1986).

Known extent of occurrence

Distributed along western and central equatorial Africa, the Demidoff’s galago occurs from Senegal to Uganda (north-west of Lake Victoria), southwards to former Zaire and north Angola; it also inhabits Bioko Island (in Eq. Guinea). Fig. 2.2.8.a was obtained from Nash et al. (1989). The separate range in Tanzania roughly approximates the extent of occurrence of the different forms of dwarf galago recently proposed as separate species (Kingdon, 1997).

This species lives mainly in primary and secondary forest, it also occurs in gallery forests, around human settlements and in plantations (Kingdon, 1971-77; Haltenorth & Diller, 1980; Macdonald, 1984).

Based on these environmental preferences, the following scores were assigned (Fig. 2.2.8.b) (Tab. 2.2.8.a):

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.2.8.c.

The elongated EO in western Africa expands into the forest block of central former Zaire. 53% of the EO is classified as suitable and 29% as moderately suitable. As the species is closely associated to gallery and riverine forests, the network of suitable areas runs almost continuously throughout the EO, but its shape is obviously far from compact and homogeneous (high AWMSI). The relatively low Index of Accordance of 48.41% probably reflects this association to gallery and riverine forests which can only be mapped approximately at the resolution of this databank. Moderately suitable areas provide an essential contribution to the continuity of the AO (see the variation of NP and LPI between the AO total and its components). In south-eastern former Zaire and Rwanda, both models identify less suitable areas. The isolated part of the EO in Tanzania is a network of forests associated to the local rivers, and the suitability is restricted to these areas: this section of the EO is small and isolated and the classification of these populations in a higher threat category is justified.