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Species Name: Zanzibar Elephant Shrew (Rhynchocyon udzungwensis)
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The Zanzibar elephant shrew is a very small insectivorous mammal, with a distinctive long, flexible snout which it utilizes for picking up little invertebrates, for example ants and termites. In addition to that, it has long and slim legs and a lengthy tail. Despite the amusing name, it is not really closely associated with the true shrew. Elephant shrews have different habits and form their own family called the Macroscelididae, in the order Macroscodentia. Elephant shrews are very shy and although certain species are pretty common, they can be hard to see. Elephant shrews are diurnal and are more active in the morning and late afternoon. They have a regular route round their territory, making use of their well-worn paths to escape predators. They usually freeze and are incredibly hard to see whenever they sense danger.
The elephant shrew is a tiny, terrestrial mammal, very agile in its habits and has only recently been widely accepted as a member of the superordinal group Afrotheria, although some still consider its relationships with other mammals to be uncertain. It is placed in the order Macroscelidea and the family Macroscelididae. Elephant shrews are widely distributed over southern Africa, with the greatest diversity to be found in the southern and eastern parts of the continent. The largest of all its species, the Zanzibar elephant shrew, lives in the ancient coral rag forests of the island. The Zanzibar elephant shrew is a terricolous species and can often be observed in the forest searching for insects. In a study conducted by Dr. Galen Rathbun in 1996, Ruvu forest was explained as being too heavily disturbed for elephant shrews to flourish and found no sign of this species. Rubio et al. (1996-1997) suggested that the disappearance of this species from Ruvu was recent and in the past, it was an area where elephant shrews habituated. Sessions and others explain that around the 1960s, Uzi island off the coast of Zanzibar was heavily planted with clove trees which were sold to the Japanese and now takes the appearance of a clove plantation. They go on to explain that the only remains of past forest in Zanzibar is located within Zanzibar National Park and the Ngezi forest private area. It is suggested that Zanzibar elephant shrews inhabit these areas of forest and do not live in any other types of habitat.
This is the largest of the elephant shrews and when in thick bush or forests, it can be confused with a very large rat. However, it likes dry, open places and is found in a variety of habitats from lowlands to the timberline. The Zanzibar elephant shrew has adapted to its primarily carnivorous diet by developing a long, mobile, flexible snout and small mouth. Periods of activity are divided by long intervals of rest during which the animal sleeps, or rather dozes, in a crudely constructed grass nest. Elephant shrews are extremely vulnerable to rapid desiccation and have a high standard of maintenance water loss, which restricts them to areas where foliage humidity is high. The heat increment of feeding and the energy cost of water loss are both reduced by the consumption of arthropods and even the smallest insects may act as alternative dietary water sources. Elephant shrews lose heat very rapidly and use torpor to conserve energy. A drop in air or body temperature usually terminates their lengthy high energy cost periods of activity. All the above features are taken to an extreme in correlation with a highly specialised insectivorous and terrestrial mode of life, by the Rufous Sengi of the East Usambara elephant shrew, a newly discovered and still undescribed species only known from the Amani Nature Reserve. Elephant shrews belong to the Afrotherian clade of placental mammals and are one of a number of taxa endemic to the African continent that have no close relatives and whose distantly related nearest kin are other African endemics. They are particularly similar to tenrecs and golden moles in their insectivorous nature.
Call it orangutan, it is probably the most well-known and most commonly seen of the island’s ten species of primate, but there the true significance of Zanzibar’s small and elusive scaly-tailed ‘little elephant’ (meaning of sengi in Swahili) becomes apparent. The fact that elephant shrews still persist in Zanzibar is a remarkable survival story given the evolutionary changes in the Indian Ocean islands over the past 20 million years. The sengi family (Macroscelididae) is confined to Africa, but the species living on the remote oceanic islands, namely the fossil form and the two Macroscinculus species on Madagascar, Mauritius and the Comoros, have all become extinct. On Zanzibar the sengi is represented by the monotypic Elephantulus rozeti. Over the last quarter of the 20th century the forest-dwelling Zanzibar elephant shrew had been listed variously as ‘rare’ and even uncertain of survival, but the past twenty years of habitat surveys have now found this insectivore to be quite widespread in dry coral rag and sand-forest habitats. From a conservation viewpoint it is one of the great success stories, achieved without the species ever becoming a specific conservation target. Thanks to a later ecological survey programme, by 2008 the IUCN had assessed E. rozeti to not be currently threatened with the population trend stable and the species still very widely distributed on Zanzibar. In spring 2004 we captured and radio-collared four Zanzibar elephant shrews for a small study of forest utilisation which was carried out simultaneously with a dung beetle population study. These sengis were located via spool-and-line tracking on selected nights then the signal traced to their nest site. No active trapping was involved. The radio-tracked sengis soon accustomed to our presence under cover of darkness and our closest observations were of a pair in the forest to the west of the Zanzibar Butterfly Centre.