PRIMATES

Primates Id code: amd301

Galagonidae
Galagoides zanzibaricus

(Matschie, 1893)

(Eng) Zanzibar galago

(Fre) Galago du Zanzibar

Taxonomic notes

Separated from G. senegalensis by Kingdon (1971-77), it is assigned to the genus Galago by some authors (Oates, 1996). According to Wilson & Reeder (1993) and Oates (1996), it includes G. z. granti (Grants’ dwarf galago) which occurs in Malawi, Mozambique, Tanzania and Zimbabwe and is sometimes treated as a distinct species (Kingdon, 1997).

IUCN threat category

Lower Risk, near threatened (LR: nt) as G. zanzibaricus. The Grants’ dwarf galago, here considered as a subspecies of G. zanzibaricus (G. z. granti) but listed by Baillie & Groombridge (1996) as a distinct species (G. granti), is classified as Data Deficient (DD).

Available information

The species has mainly been studied in the Kenyan coastal forest. The main aspects of its ecology were investigated by Harcourt & Bearder (1989); the authors researched the species at Diani Beach Forest (Kenya) and focused mainly on its habitat and behaviour. Information on the species' social behaviour is also found in Harcourt & Nash (1986) and Nash (1986). Its reproductive behaviour is analysed in Harcourt (1986), which also includes notes on the species' habitat. The species' occurrence in Malawi is described in Courtenay & Bearder (1989). A detailed account of the species' ecology in Southern Africa is found in Mills & Hes (1997) and Skinner & Smithers (1990). General information on the ecology of the species is reported in Estes (1991), Kingdon (1971-77, 1997), and Stuart & Stuart (1997). Status, threats, and conservation issues are discussed in Lee et al. (1988) and Oates (1996).

Known extent of occurrence

The Zanzibar galago is present along the east African coast from Somalia to Mozambique and on Zanzibar Island (but not on Pemba and Mafia). The distribution map (Fig. 2.2.10.a) was obtained from the maps in Skinner & Smithers (1990) and Nash et al. (1989). The northern boundary needs clarification as some authors place it at the Tana River in Kenya (Lee et al., 1988; Kingdon, 1997).

Categorical-discrete (CD) distribution model

Found in montane and lowland coastal forests, the species also occurs in riverine forests and cultivation mosaics (Nash et al., 1989; Lee et al., 1988; Kingdon, 1971-77).

Based on these environmental preferences, the following scores were assigned (Fig. 2.2.10.b) (2.2.10.a):

Scores
1	Forests.
2	Forest mosaics.
3(*)	Savannas and croplands.
(*) Scores increased for vegetation types occurring inside a 1-km buffer around permanent water

suitable		moderately suitable		unsuitable		Total
km²	%	km²	%	km²	%	km²	%
8 614	1	437 044	33	887 651	67	1 333 309	100

Tab 2.2.10.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	186	46	56	0.13	1.12	1.38
moderately suitable	916	476	7 945	53.61	1.58	31.8
Total AO	883	504	8 293	54.94	1.59	32.01

Tab 2.2.10.b: Area of Occupancy fragmentation indexes.

Probabilistic-continuous (PC) distribution model

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.2.10.c.

Validation

No occurrence of the species within the four sample countries.

Comments and conservation issues

The EO is very large as it includes a wide portion of south-eastern Africa, but the species' AO is much smaller, restricted to the small forest remnants and the gallery and riverine forests associated to the network of rivers. Suitable areas are only 1% of the total EO and the moderately suitable areas account for a further 33%; most of the EO (67%) is found to be unsuitable. The AO is therefore highly fragmented and of a very discontinuous shape, as shown by the NP and AWMSI. The internal areas of Somalia and Kenya appear to be the most unsuitable areas, while the forest network is often continuous in the rest of the EO (LPI = 54.94%). However, the species is poorly known and its elusive behaviour does not make it easy to find and study it. Its overall conservation status is Lower Risk, and about 12% of the total AO is included in existing protected areas. Local populations and subspecies may be highly endangered.

SUITABILITY CLASS	inside	outside	Total
suitable	0.05	0.60	0.65
moderately suitable	3.01	29.77	32.78
unsuitable	5.94	60.64	66.58
Total	9	91	100

Tab 2.2.10.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.

References

Baillie J., Groombridge B. (Eds) (1996). 1996 IUCN Red List of Threatened Animals. IUCN Species Survival Commission.

Courtenay D.O., Bearder S.K. (1989). The taxonomic status and distribution of bushbabies in Malawi with enphasis on the significance of vocalizations. Int J. Primatol.: 10, 17-34.

Estes R.D. (1991). The Behavior Guide to African Mammals. Including Hoofed Mammals, Carnivores, Primates. The University of California Press.

Harcourt A., Nash L.T. (1986). Social organization of galagos in Kenyan coastal forests: I Galago zanzibaricus. Amer. J. Primatol.: 10, 339-355.

Harcourt C.S. (1986). Galago zanzibaricus: birth seasonality, litter size and perinatal behavior of females. J. Zool., Lond.: A 210, 451-457.

Harcourt C.S., Bearder S.K. (1989). A comparison of Galago moholi in South Africa with Galago zanzibaricus in Kenya. Int J. Primatol.: 10, 35-45.

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.

Lee P.C., Thornback J., Bennet E.L. (1988). Threatened Primates of Africa. IUCN, Gland - Switzerland and Cambridge, UK.

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.

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.

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.