Zanzibar archipelago is part of the ecoregion dominated by the Nothern Zanzibar-Inhambane forest mosaic covering part of the coastal areas of East Africa. It is a region of rich biodiversity with species ranging from the purely mountainous type to those thriving well under coastal aquatic or marine habitats. However, the list of Zanzibar faunae is not broad compared to that of the adjacent areas of the mainland of East Africa. This is particularly true for higher animals such as birds, reptiles, amphibians and mammals but for lower animals differences may not be substantial. Unguja seems to have much wider faunal list compared to Pemba but there are some families only available in Pemba and not found elsewhere in this region. Therefore, there is a very high level of endemism particularly on the island of Pemba.
Notwithstanding the disappointing comparison of Zanzibar fauna to that of the mainland, visitors will be surprised by the diversity of species found in the islands of Unguja and Pemba. Ironic, however, many visitors are interested in the list of animals endemic to Zanzibar and no wonder we witness an enormous interest on the Red Colobus Monkey or Kima Punju in Swahili (Procolobus kirkii) and the Pemba Flying Fox, Pteropus voeltzkowi (Swahili: Popo wa Pemba). For natives of Zanzibar, who have seen colourful lizards, exciting frogs and toads, variety of birds, and other animals freely roaming in the wilderness, the attention given to few endemic species tends to understate the reality.
On this section, a brief description of Zanzibar faunae is given. However, only terrestrial or aquatic species are covered and for general account of marine species, please visit the marine and fisheries resouces on this website.
In general, Zanzibar has a huge collection of arthropods. Insects form the largest group among the arthropods and its not easy to present a complete list of all the species found in Zanzibar. However, giant butterflies, grasshopers, leafhopers, moths, dragonflies, wasps, honeybees, mantids, beetles, ants, and many more are abundant. Insects are often accused of either being nuisance or a threat to human life by directly damaging agricultural crops and products or acting as vectors working to spread some deadly diseases. Nevertheless, insects are ecologically very useful organisms working to either degrade organic matter, cross-pollinate flowering plants or even produce useful products, the case of honeybees. They are part of the ecosystem and plays a significant role in maintaining the ecological balance of the existing species.
Common insect vectors and pests in Zanzibar include mosquitoes and houseflies. Mosquitoes, types - anopheles and culex, carry parasites that cause malaria and elephantiasis in humans. These are the two diseases affecting a large section of the population. Despite rigorous eradication campaigns it has not been possible to slow down the growth of mosquito populations in Zanzibar.
There are also a number of agriculturally important pests such as, the coconut bug (Pseudotheraptus wayi), coconut beetles, weevils (banana and sweet potato), moths (Lepidoptera) and many kinds of sucking bugs (Hemiptera) including Cassava mealy bugs (Phenacoccus manihoti). Tsetse flies (ndorobo in Swahili) of the species Glossina austeni, which are vectors of tyrpanosomiasis in livestock and sleeping sickness in man have been eradicated in Zanzibar by a project that applied the Sterile Insect Technique (SIT).
Other arthropods in Zanzibar inlude the arachnids (spiders, scorpions and ticks). A number of spider and scorpion species are found but local knowledge on the characteristic features of these species is very limited. Ticks are mainly of agricultural significance due to their role in spreading livestock diseases. Common types include some species of hard ticks such as the Brown ear tick or Kupe wekundu in Swahili (Rhipicephalus appendiculutus), the blue tick or Kupe vitumbo in Swahili (Boophilus spp), and Amblyomma ticks, notably A. variegatum or Kupe vijiwe in Swahili.
Several kinds of centipedes, some mildly poisonous, are found in Zanzibar but for many, interest is focused on the giant millipedes. Thought to have been introduced, sometimes during the Omanis rule, the 200 plus legged creatures originally confined to few localities are now observed in many corners of the archipelago.
Crustaceans are abundant but mainly of marine origin. There are however a number of species inhabiting the wet as well as the dry areas of the islands. An example would be the famous giant coconut crab found on Chumbe island. In fact, this crab is found in many other places and very abundant in the southern coast of Pemba. In southern Pemba, it is locally known as "tuu", the name seems to have been derived from the sound this crab make when cracking a coconut (my guess!). In Pemba, some semi-terrestrial crabs, locall known as "Kaa-dondo" can be found close to streams and lakes and under rocks in the drier coral rag areas.
Annelids and Molluscs
Annelids (e.g. earthworms and leeches) and Molluscs (e.g. snails and slugs) are abundant in Zanzibar. Earthworms are everywhere but more numerous in the deep soil areas on the western side of Unguja and Pemba islands. Leeches (Swahili: mwata or ruba) are common in some parts of Unguja and nothern Pemba.
In Zanzibar, land snails include one species of the giant land snail (Achatina reticulata) that can reach a length of more than 15 cm and the smaller ( Achatina iredalei). There are also aquatic snails belonging to the Bulinus africanus group (e.g. B. globosus and B. nasutus) that are known to act as intermediate hosts for the parasite that cause Urinary Schistosomiasis. Slugs, which are closely related to snails but have no external shells, are found in Zanzibar in wet or moist areas.
Zanzibar's mammal population is very small with only 54 terrestrial species, out of which 23 species are bats. Most of the mammals are found in Unguja island with very few of them found in the sister island of Pemba. Major mammal species include:
- Red Colobus monkey (Procolobus kirkii) - are the common inhabitants of Jozani forest and occupy a remarkable array of habitats including the ground water forest, coral rag forest, fruit tree gardens and mangrove forest. Their population numbers to about 1500 moving in groups of 10 - 30 individuals. It is absent in Pemba island
- Bush Tailed Mongoose (Bdeogale crassicauda tenuis) - the nocturnal and shy mongoose inhabits the coral rag forest of the south-eastern area of Unguja island but in Pemba it is found in the deep soil areas on the western side of the island. The local name in Pemba is "Chonjwe" and hobby hunters usually encounter this mongoose when hunting for the Small Indian civet.
- Zanzibar Tree Hyrax (Dendrohyrax validus nuemanni) - also nocturnal, this tree hyrax is common in Jozani and its habitat comprises trees and caves in coral rag forest. It is believed to be the earliest hyrax species adapted to forest life and possesses the characteristic of having four digits on its front feet and three on its hind feet. It is absent in Pemba island.
- Zanzibar Slender Mongoose (Herpestes sanguineus rufescens) - is a common resident of coral rag forest. Acute sight, hearing and smell allow the animal to elude larger carnivores and birds that prey on it. It is absent in Pemba island.
- Zanzibar Sunni or Dwarf antelope (Neotragus moschatus moschatus) - also a coral rag animal and commonly found in Jozani forest especially among Psiadia arabica and Todalia spp trees. Although not a water dependant species, it is usually found near water sources. Lifelong pairs protect a territory of 3 ha in which they raise one fawn per year under favourable conditions.
- Zanzibar Leopard (Panthera pardus adersi) - Its existence is debatable but believed to inhabit some ares of Unguja island. The population size is totally not known, however, it is associated with witchcraft and is believed to be employed by evil-doers who keep the animal to scare others off their homes.
- Zanzibar Giant Rat (Cricetomys gambianus cosensi) - is a species inhabiting the coral rag forest, common in Jozani forest but rare in other areas of Zanzibar. It reaches up to a meter in length, including the tail. The burrow sites are changed in two weeks to reduce the risk of predation.
- Four-Toed Elephant Shrew (Petrodromus tetradactyla zanzibaricus) - is a species that inhabits primarily coral rag areas of Unguja island in low canopy forests; under dry leaves, and non-flooding areas. It is rarely seen and survives because of its nocturnal lifestyle.
- House Shrew or Indian Musk Shrew (Suncus murinus) - is abundant in Unguja island. Its habitats are coral rag forest and non flooding areas. It is an important food source for omnivores and carnivores. It is an exotic species from south Asia with a body length of 19 - 20 m.
- Black and Rufous Elephant Shrew (Rhynchocyon petersi adersi) - is a stable species in Unguja island. It is listed under IUCN's threatened species and only found in East Africa. Its habitats range from low-lying coral rag forest to non-flooding areas.
- Lesser Bushbaby (Galago senegalensis zanzibaricus) - is a common species of Zanzibar and Africa as a whole. Its habitats are ground water forest, coral rag forest possibly mangrove forest. The lesser bushbaby is distinguished from greater bushbaby by its noticeable white patch stretching from forehead to nose. It is nocturnal.
- Greater bushbaby (Otolemur garnetti garnetti) - is common in Zanzibar and Africa as a whole. In Zanzibar, its habitat include the ground water forest, coral rag forest and possibly mangrove forest. It possesses a muscular body for its arboreal lifestyle. It is nocturnal.
- Syke's monkey (Cercopithecus mitis albogularies) - It is a common species in Zanzibar as well as in Africa. Its habitats are ground water forest, coral rag forest and mangrove forest. The species is seen daily foraging with Red colobus monkeys in plantation and ground water forests of Jozani forest.
- African civet (Viverra civetta schwarzi) - known in Zanzibar as Fungo, was imported by the Arabs because of its musk gland secretions. In Unguja island, its habitat is in coral rag forest and the grassland. It is active at night, often near water sources. It is absent in Pemba
- Small Indian civet (Viverricula indica rasse) - is an exotic species and its secretions were used in perfume. Locally known as "ngawa", it is common throughout Zanzibar (i.e. Unguja and Pemba). Its habitat ranges from Ground water forest during the drought, coral rag forest and grassland. It is solitary except during breeding.
- Bushpig (Potamochocrus porcuss spp) - It is common in Zanzibar and Africa and inhabits all vegetations of Jozani forest, also found in other parts of Zanzibar. It is vermin to agricultural crops. It requires water daily and is a good swimmer.
- Zanzibar Duiker or Ader's Duiker (Cephalophus adersi) - is near endemic species and rare in Unguja island. It weighs an average of 8 - 9 Kgs. Zanzibar Duiker is also found in pockets of mainland and inhabits dense undergrowth in coral rag thicket. It possesses acute hearing for protection.
- Sundevall's Blue Duiker (Cephalophus monticola sundevalli) - is a common species of Jozani and Unguja island. It lives in dense undergrowth of coral rag thicket. This diurnal species marks its territory by horning the trees and depositing scent from preorbital glands on vegetations. It is absent in Pemba island
- Red-Legged Sun Squirrel (Heliosciurus rufobrachium dolosus) - Its habitats range from coral rag forest to plantation forest. It differs from Red Bush Squirrel by possessing a black, ringed tail. It is absent in Pemba island
- Red Bush Squirrel (Paraxesus palliatus frerei) - It is a common species of Zanzibar and Africa at large, which in Zanzibar resides in coral rag forest and ground water forest. Its ecology is not well known. It is absent in Pemba island