Elephant shrew (order Macroscelidea), also called sengi, any of approximately 20 species of rat-sized African mammals named for their long, tapered, and flexible snout (proboscis). All have slim bodies, slender limbs, and very long hind legs and feet. Although they resemble shrews, they are not insectivores but constitute the mammalian order Macroscelidea.
Elephant shrews are terrestrial and are active during the day. Their ears and eyes are large, and, when alarmed, they run on their toes swiftly along paths they construct and maintain, sometimes leaping over obstacles. When foraging, they move along the pathways, using their paws and the constantly moving proboscis to turn over leaf litter and soil in search of prey, which consists of small insects (especially ants and termites), other arthropods, and earthworms. Gestation lasts two months, and litters contain one or two well-developed young.
Checkered elephant shrews (Rhynchocyon cirnei) weigh about half a kilogram (1.1 pounds), with a body 23 to 31 cm (9 to 12 inches) long and a slightly shorter tail (18 to 25 cm). The fur is short, stiff, and glossy. Upperparts may be patterned with chestnut and buff; they may be orange on the forequarters, changing to dark red and then black on the rump, or uniformly dark amber with a shiny golden rump. The bicoloured tail is finely haired and appears bare. These elegant long-legged animals are similar in body form to small forest antelopes (see dik-dik; duiker). They live only in East Africa, where they inhabit tropical forests (including deciduous lowland and montane forests) with well-drained soils and carpets of leaf litter. Nests are made of dry leaves on the open forest floor.
The largest species, the giant elephant shrew (R. udzungwensis), weighs about 0.7 kg (1.5 pounds) and inhabits two forested areas within the Udzungwa Mountains of Tanzania.
The smaller species weigh 30 to 280 grams, with bodies 9 to 22 cm long and shorter tails of 8 to 18 cm. The soft, dense fur ranges from grayish brown to dark brown, in tones usually matching the soil where they live. They are found in the uplands of southern, eastern, and extreme northwestern Africa, inhabiting dry forests and scrub, savannas, open country covered by sparse shrubs or grass, semiarid and rocky habitats, and sandy, sparsely vegetated plains. They rest and den in burrows, rock crevices, depressions in the ground, and termite mounds, beneath fallen tree trunks, among tree roots, or in dense underbrush.
In addition to the checkered elephant shrews, the family Macroscelididae also includes the long-eared elephant shrews (genus Elephantulus), the round-eared sengis (Macroscelides proboscideus, M. flavicaudatus, and M. micus), and the four-toed elephant shrew (Petrodromus tetradactylus); those three genera are classified together in a subfamily separate from Rhynchocyon. Macroscelididae is the only family in the order Macroscelidea. There are eight extinct genera, some of which had teeth similar to antelopes’ and were probably herbivores. The evolutionary history of elephant shrews is confined to Africa and dates to the Late Eocene (41.3 to 33.9 million years ago). Their closest relatives were thought to be tree shrews and insectivores, but since the 1950s elephant shrews have been recognized as a distinct order. They are possibly related to rabbits and rodents, although molecular data suggest that they may be more closely related to an ancient group that gave rise to the aardvarks, elephants, hyraxes, and sirenians.