Elephant shrews, also known as sengis or jumping shrews, are small, slim-bodied mammals with a distinct, flexible snout that resembles a tiny elephant trunk. Their appearance is a mix between shrews and elephants, which describes their name. However, phylogenetic analysis revealed that they are more closely related to elephants than shrews.
These mammals are primarily insectivorous and are native to Africa, except for regions in western Africa and the Sahara. Despite their name, elephant shrews are not true shrews (family Soricidae). Instead, they belong to their own family, Macroscelididae, under the superorder Afrotheria, which also includes elephants, sea cows, and aardvarks.
Known for their incredible agility, elephant shrews are among the fastest small mammals, capable of reaching speeds of up to 17.9 mph (28.8 km/h). Currently, 20 living species of elephant shrews are recognized, classified into six genera.
They vary greatly in size depending on the species. Most measure between 3.9 to 11.8 in (10 to 30 cm) in length and weigh between 1.8 to 17.6 oz (50 to 500 gm).
The largest species, the gray-faced sengi (Rhynchocyon udzungwensis), is 11.4–12.6 in (29 to 32 cm) long, with an additional tail length of 9 to 10 in (23 to 26 cm). It weighs approximately 1.5 lb (700 gm), making it the heaviest of all elephant shrews.
In contrast, the short-eared elephant shrew (Macroscelides micus) is the smallest species. A mature adult measures just 7.3 in (18.5 cm) in length and weighs less than 1 oz (around 28 gm).
Elephant shrews have long, pointed heads with flexible, trunk-like snouts, complemented by long, scaly tails and thin, elongated legs that are proportionally large compared to their body. Their large eyes and ears enhance their sharp senses.
The body coloration varies significantly among species. For example, the checkered elephant shrew (Rhynchocyon cirnei) has short, glossy, and stiff fur that ranges from chestnut to buff, transitioning to dark red and black on the rump. In contrast, giant sengis (genus Rhynchocyon) display a striking mix of light yellow, red, and black. Smaller species of elephant shrews typically have soft, dense fur in shades of gray to dark brown.
Their skulls are distinguished by complete auditory bullae and zygomatic arches, large jugals, and fenestrated palates. Like ungulates, they have high-crowned cheek teeth, with large canines having two roots and quadrate molars. The dental formula for this group is 1-3.1.4.2/3.1.4.2-3 = 36-42.
Although elephant shrews have relatively larger brains than other mammalian insectivores, their olfactory lobes are particularly small.
In 1997, the zoologist Jonathan Kingdon suggested that these mammals be named sengis (derived from the Bantu languages of Africa), besides elephant shrews. A year later, this group was classified as members of the other group, Afrotheria.
Currently, the 20 species of elephant shrews are grouped under 6 genera.
They are endemic to Africa, except in western Africa and the Sahara. Smaller species are restricted to the uplands of eastern, southern, and northwestern Africa, particularly in scrubs, dry forests, savannas, semi-arid and rocky regions, and sparsely vegetated plains.
Elephant shrews are primarily insectivorous, relying on a diet of insects such as beetles, ants, and termites. They also consume a variety of other invertebrates, including earthworms, centipedes, millipedes, and spiders, which they often find in leaf litter. In addition to their insect-based diet, elephant shrews occasionally supplement their meals with plant matter, including fresh leaves, seeds, and small fruits.
These animals are terrestrial and diurnal, spending the majority of their day (about 80% of their time) foraging actively. They create a network of cleared pathways through the undergrowth, which not only aid in efficient foraging but also serve as escape routes, allowing them to flee from predators.
They are difficult to trap and are well-camouflaged, thus evading the grip of the enemies.
They usually sense prey with their long nose and use their tongues to flick food into their mouths. They also turn over leaf litter using their paws and snouts to search for insects.
Invertebrates, such as earthworms, are first pinned to the ground with their forefoot and then chewed in bits using the cheek teeth. During eating, tiny pieces of the worm’s body drop to the ground, which are later flicked up using the tongue.
Though primarily solitary, many species, like the black and rufous elephant shrew, live in monogamous pairs. These couples share common home territories of several acres, which they defend actively. They mark the territories with secretions from specialized scent glands found on the underside of their tails. If neighbors try to intrude on a territory, they are aggressively attacked with snaps and kicks, accompanied by screaming.
Despite living in pairs, elephant shrews do not usually care for each other. In fact, their sole purpose of associating with the other sex is for reproduction.
They have an average lifespan of 2.5 to 4 years in the wild, though they are often found to survive up to 11 years in captivity.
The breeding season of elephant shrews varies by species. For example, round-eared elephant shrews breed from June to January, while North African elephant shrews breed between January and August. In contrast, the golden-rumped sengi breeds year-round, showing no specific seasonal preference.
During courtship, male elephant shrews release scents to attract females and aggressively guard their mates to maintain their pair bonds. After mating for several days, the female undergoes a gestation period of about 45 to 60 days, depending on the species. She gives birth to litters of one to three precocial (well-developed) young several times a year.
Approximately five days after birth, the mother begins feeding the young mashed insects alongside milk. Nursing sessions are brief, lasting less than a minute daily. Although males do not participate in direct parental care, they vigilantly guard the female and her offspring from rival males.
By around 15 days post-birth, the young start exploring their environment, gradually reducing their reliance on their mother. They become fully independent by 25 days and begin establishing their home ranges, which can span approximately 0.39 sq. mi (1 sq. km). At about 40 days, the parents show aggression toward their young, compelling them to leave and live independently.
Elephant shrews reach sexual maturity within 41 to 46 days, ensuring that they reproduce quickly to sustain their populations.
They are usually preyed upon by birds of prey, lizards, snakes, and large mammals like foxes and mustelids.
Currently, the golden-rumped sengi is listed as Endangered (EN) under the IUCN Red List, while the grey-faced sengi is considered Vulnerable (VU).
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