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Primates
Id code: amd060Galagonidae
Otolemur crassicaudatus
(É. Geoffroy, 1812)
(Eng) Large-eared greater bushbaby
(Fre) Galago à queue épaisse
Taxonomic notes
Placed in a separate genus by Groves (1974), the greater galago includes several subspecies (Meester & Setzer, 1971). According to Kingdon (1997) O. c. argentatus in Kenya might be a distinct species, while a newly described form (still without a scientific name) may have been distinguished from the greater galago in coastal valleys close to Lindi (Mozambique). Further investigation is clearly required.
IUCN threat category
Not listed.
Available information
This species has been quite intensely studied, and information is available on the main aspects of its ecology. A description of the habitat in which it occurs is found in several authors (Doyle & Bearder, 1977; Estes, 1991; Kingdon, 1971-77, 1997; Nash et al., 1989), but no specific studies on habitat use and requirements have been carried out. Authors focused mainly on behavioural aspects of the species' ecology. The species' social organisation was investigated at Gedi (Kenya) by Nash (1986). In the Northern Transvaal (South Africa), Clark focused on its intraspecific relationships (Clark, 1978a, 1985). A captive study on the species' reproduction was carried out by Izard & Simons (1986). Population structure was investigated in the northern Transvaal by Clark (1978b). The species' density in the Jubba Valley (Somalia) is analysed in Varty (1988). Data on the species' occurrence and notes on its ecology are available for most of South Africa (Bruton, 1978; Pringle, 1974), while its overall distribution is discussed in Masters (1985, 1988), and Nash et al. (1989). A sound account of the ecology of the species in Southern Africa is found in Mills & Hes (1997) and Skinner & Smithers (1990). General information on its ecology is reported by several authors (Estes, 1991; Kingdon, 1971-77, 1997; Stuart & Stuart, 1997). Status and threats are discussed in Oates (1996).
Known extent of occurrence
This species ranges widely from Kenya, Tanzania and Rwanda, southwards to Natal (South Africa) and westwards to Angola (Wilson & Reeder, 1993). A first rough map was obtained from Skinner & Smithers (1990) then updated using the more recent information in Kingdon (1997). The revision was also based on the river network. (Fig. 2.2.11.a)
Categorical-discrete (CD) distribution model
This species occurs in inland and coastal forests and riparian vegetation; in the north-eastern portion of the range it is primarily associated to woodland savanna (Nash et al., 1989; Doyle & Bearder, 1977; Kingdon, 1997).
Based on these environmental preferences, the following scores were assigned (Fig. 2.2.11.b) (Tab. 2.2.11.a):
|
Score(*) |
|
|
1 |
Forests; woodlands and woodland mosaics. |
|
2 |
Forest mosaics; bushlands, thickets and croplands. |
|
3 |
Grasslands, arid shrublands and their mosaics. |
|
(*) Scores increased for vegetation types occurring inside a 1-km buffer around permanent water |
|
|
suitable |
moderately suitable |
unsuitable |
Total |
||||
|
km2 |
% |
km2 |
% |
km2 |
% |
km2 |
% |
|
3 422 703 |
72 |
1 047 083 |
22 |
284 146 |
6 |
4 753 932 |
100 |
Tab 2.2.11.a: Cumulative size (km2) of areas pertaining to each environmental suitability class within the Extent of Occurrence.
|
Number Patches (NP) |
Mean Patch Size (MPS) km2 |
Patch Size SD (PSSD) km2 |
Largest Patch Index (LPI) % |
Mean Shape Index (MSI) |
Area-Weighted Mean Shape Index (AWMSI) |
|
|
suitable |
735 |
4 656 |
121 083 |
73.5 |
1.37 |
44.77 |
|
moderately suitable |
5 356 |
195 |
1 913 |
1.93 |
1.31 |
7.52 |
|
Total AO |
147 |
30 404 |
366 528 |
99.77 |
1.25 |
14.27 |
Tab 2.2.11.b: Area of Occupancy fragmentation indexes.
Probabilistic-continuous (PC) distribution model
The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.2.11.c.
Validation
Less then 1% of the EO is included in the four sample areas.
Comments and conservation issues
This species has a more flexible preference for vegetation types and the suitability of its EO is definitely higher than that of most similar species associated to riverine and gallery forests. The whole EO has a high suitability and the combination of suitable and moderately suitable areas provides an almost continuous AO with little fragmentation. The very irregular shape of the suitable areas (AWMSI) is also significantly mitigated by the less suitable areas and the total AO is much more compact. About 10% of the total AO is included in protected areas.
|
SUITABILITY CLASS |
inside |
outside |
Total |
|
suitable |
6.67 |
65.33 |
72 |
|
moderately suitable |
2.78 |
19.24 |
22.03 |
|
unsuitable |
1.53 |
4.45 |
5.98 |
|
Total |
10.97 |
89.03 |
100 |
Tab 2.2.11.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.
References
Bruton M.N. (1978). Recent mammal records from eastern Tongaland in Kwazulu, with notes on Hippopotamus in lake Sibaka. Lammergeyer: 24, 19-27.
Clark A.B. (1978a). Olfactory communication, Galago crassicaudatus, and the social life of prosimians. In: Chivers O.J., Lane-Petter, W. (Eds). Recent Advances in Primatology. Academic Press, London and New York:109-117.
Clark A.B. (1978b). Sex ratio and local resource competition in a prosimian primate. Science: 201, 163-165.
Clark A.B. (1985). Sociality in a nocturnal "solitary" prosimian: Galago crassicaudatus. Int J. Primatol.: 6, 581-600.
Doyle G.A., Bearder S.K. (1977). The Galagines of South Africa. In: Bourne G.H. (Ed.). Primate Conservation. Academic Press, London and New York; chap. 1: 2-37.
Estes R.D. (1991). The Behavior Guide to African Mammals. Including Hoofed Mammals, Carnivores, Primates. The University of California Press.
Groves C.P. (1974). Taxonomy and phylogeny of prosimians. In: Martin R.D., Doyle G.A., Walker A.C. (Eds). Prosimian Biology. University of Pittsburgh Press, Pittsburgh.
Izard M.K., Simons E.L. (1986). Management of reproduction in a breeding colony of bushbabies. In: Else J.G., Lee P.C. (Eds). Primate ecology and conservation. Selected Proceedings of the 10th Congress Int. Primatological Society, Nairobi, Kenya (July 1984). Cambridge University Press, Cambridge, U.K: chap. VI.6, 315-324.
Kingdon J. (1971-77). East African Mammals. VOL I: primates, hyraces, pangolins, protoungulates, sirenians. VOL IIA: Insectivores and bats. VOL IIB: hares and rodents. VOL IIIA: carnivores. VOL IIIB: large mammals. VOL IIIC: bovids. VOL IIID: bovids. Academic Press, London and New York.
Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World.
Masters J.C. (1985). Geographic distributions of karyotypes and morphotypes within the Greater Galagines. Folia Primatol.: 46, 127-141.
Masters J.C. (1988). Speciation in the greater galagos (Prosimii: Galagidae): review and synthesis. Biol. J. Linn. Soc.: 34, 149-174.
Meester J., Setzer H.W. (Eds) (1971). The Mammals of Africa, an Identification Manual. Smithsonian Institution Press, Washington D.C.
Mills G., Hes L. (1997). The complete book of Southern African mammals. Struik Publishers.
Nash L.T. (1986). Social organization of two sympatric galagos at Gedi, Kenya. In: Else J.G., Lee P.C. (Eds). Primate ecology and conservation. Selected Proceedings of the 10th Congress Int. Primatological Society, Nairobi, Kenya (July 1984). Cambridge University Press, Cambridge, U.K: chap. III.4, 125-132.
Nash L.T., Bearder S.K., Olson T.R. (1989). Synopsis of Galago species characteristics. Int J. Primatol.: 10, 57-80.
Oates J.F. (1996). African Primates Status Survey and Conservation Action plan. IUCN/SSC Primate Specialist Group.
Pringle J.A. (1974). The distribution of mammals in Natal. Part I. Primates, Hyracoidea, Lagomorpha (except Lepus), Pholidota and Tubulidentata. Ann. Natal Mus.: 22(1), 173-186.
Skinner J.D., Smithers R.H.N. (1990). The mammals of the Southern African subregion. University of Pretoria, Pretoria.
Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers.
Varty N. (1988). Mammals and problems of their conservation in the riverine forests of the Jubba Valley, southern Somalia. Tropical Zoology: 1, 179-192.
Wilson D.E., Reeder D.M. (Eds) (1993). Mammal Species of the World: A Taxonomic and Geographic Reference. Second edition. Smithsonian Institution Press, Washington D.C.