The distinctive-looking little mammals in the African family Macroscelididae are known as elephant shrews or (from the Swahili) sengis. Despite the name, elephant shrews are not closely related to shrews--in fact, they are members of the Afrotheria and therefore more closely related to elephants (Seiffert 2007 and references therein)!
Elephant shrews are the size of mice or rats, ranging in length from 100 to 300 mm and in weight from 25 to 700 g. They have large eyes and ears, slender limbs, and a long, bare tail. A long tubular snout protruding from a strongly tapered skull accounts for the name "elephant shrew". All living elephant shrew species are specialized invertebrate-feeders, often feeding on ants especially. The fine-boned "soft-furred elephant shrew" lineage (subfamily Macroscelidinae) and the more robust "giant elephant shrew" lineage (subfamily Rhynchocyoninae) apparently diverged at least 25 to 35 million years ago. The macroscelidines are superficial surface-gleaners of small invertebrates (and occasionally fruits and seeds) in shaded but dry environments; the rhynchocyanines (represented only by Rhynchocyon) are found in moister habitats. where they forage for invertebrates by actively turning over leaf litter. Elephant-shrew species that have been studied are all socially monogamous, an unusual trait among mammals. (Kingdon 1997; Smit et al. 2011 and references therein)
The long, powerful hindlegs of elephant shrews ("Macroscelididae" means "big thigh") allow them to make vertical leaps from a standing position and to sustain their rapid, bounding escape from potential predators. Elephant shrews are almost exclusively diurnal. Reliance on shelters or burrows varies among species, but the giant elephant shrews use dry leaf litter to construct multiple 1 m-wide leaf mound shelters which they pile over shallow body-sized scoops in the soil. These mounds, which are constructed in the early morning, are used mainly as night shelters and as nurseries for their offspring. (Kingdon 1997; Smit et al. 2011 and references therein)
The family Macroscelididae as typically treated includes four genera and 17 species. The genera Macroscelides and Petrodromus are monotypic (i.e., each includes just a single species, the former a southwestern African gravel plain specialist and the latter having a southern, eastern, and central African distribution characterized by a wide habitat tolerance). Rhynchocyon includes four forest species found in eastern and central Africa (including one, R. udzungwensis, discovered only in 2005 and formally described by Rovero et al. in 2008) and Elephantulus includes 11 species with a range of habitat associations (including one, E. pilicaudus, that was formally recognized as distinct from E. edwardii, by Smit et al., only in 2008). Of all the elephant shrews, only E. rozeti occurs north of the Sahara (Smit et al. 2011). Recent investigations have supported the earlier suggestion that Elephantulus, as currently described, is not monophyletic (i.e., this group does not include all the descendants of the shared ancestor) and that there are grounds for subsuming Petrodromus and Macroscelides in Elephantulus (Douady et al. 2003; Smit et al. 2011).
Believe it or not, according to most biologists the sengi(familyMacroscelididae), or elephant shrew, is related to the elephant, and not the shrew, as previously believed because of their superficial resemblance. Sengis are grouped together in the superorder Afrotheria with elephants and other African mammals like the sea cows, hyraxes, tenrecs, golden moles and aardvarks.
17 recognised species of sengis are spread out over 6 African countries exclusively, and can be found in almost any type of habitat, from thick forests and woodlands to savannahs and deserts, depending on the species.
Even though body proportions are quite similar and size can vary from 22 to 30 cm, the sengi’s weight can range from 25 grams forMacroscelidesspecies to 700 grams forRhynchocyonspecies, which includes the largest as well as the most colourful sengis – like the one pictured above. They are called elephant shrews because of their long, trunk-like noses, which they use to smell out those tasty creepy crawlies. The sengi has long, slim limb bones adapted for running, a hunchbacked posture and a long tail. The diet of a sengi is made up almost entirely out of insects like grubs, spiders, beetles, termites and ants, and unlike many other small mammals, most species are diurnal and spend their waking hours during dusk and dawn, out and about munching yummy bugs. Elephant shrews are monogamous and mate for life! They don’t actually spend that much time together, but have scented trails to check up on each other’s whereabouts. These trails are also used to easily escape their predators, which may include birds of prey, big lizards and snakes (watch the videohere!). Sengis are not very friendly towards strangers, and will perform all kinds of dramatic acts including screaming, snapping and kicking to drive away the unwanted neighbours. Females give birth four or five times a year to fully haired, well developed new-borns, after a gestation period of about 2 months.According to the IUCN Red List of mammals, most of the sengi species are considered as ‘Least Concern’. Three of theElephantulusspecies are listed as ‘Data Deficient’ while all four species of giant sengis are at risk (one ‘Endangered’, two ‘Vulnerable’ and another ‘Near Threatened’). Forest fragmentation is the main threat in all cases, while subsistence hunting for food may also play a role in some areas.
Interesting fact:
Sometimes called the jumping shrew, some sengi species, like the checkered elephant shrew, can leap almost one metre into the air!
For more information on MammalMAP, visit the MammalMAPvirtual museumorblog.
Elephant shrews, also called jumping shrews or sengis, are small insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order Macroscelidea. Their traditional common English name "elephant shrew" comes from a perceived resemblance between their long noses and the trunk of an elephant, and their superficial similarity with shrews (family Soricidae) in the order Eulipotyphla. However, phylogenetic analysis has revealed that elephant shrews are not properly classified with true shrews, but are in fact more closely related to elephants than to shrews.[4] In 1997, the biologist Jonathan Kingdon proposed that they instead be called "sengis" (singular sengi),[5] a term derived from the Bantu languages of Africa, and in 1998, they were classified into the new clade Afrotheria.[6]
They are widely distributed across the southern part of Africa, and although common nowhere, can be found in almost any type of habitat, from the Namib Desert to boulder-strewn outcrops in South Africa to thick forest. One species, the North African elephant shrew, remains in the semi-arid, mountainous country in the far northwest of Africa. The Somali elephant shrew went unobserved from 1968 to 2020 but was rediscovered by a group of scientists in Djibouti.[7]
The creature is one of the fastest small mammals, having been recorded to reach speeds of 28.8 kilometres per hour (17.9 mph).[8] Compared to other mammalian insectivores, sengis have relatively large brains.[9]
Elephant shrews are small, quadrupedal, insectivorous mammals resembling rodents or opossums, with scaly tails, long snouts, and legs quite long for their size, which are used to move from one place to another like rabbits. They vary in size from about 10 to 30 centimetres (3.9 to 11.8 in), from 50 to 500 grams (1.8 to 17.6 oz).The body weight of the new species is about 700 g, which is 25–50% greater than any other giant sengi. The new Rhynchocyon is only known from two populations that cover about 300 km2 of montane forest. It has an estimated density of 50–80 individuals km−2 The short-eared elephant shrew has an average size of 150 mm (5.9 in). Although the size of the trunk varies among species, all are able to twist it about in search of food. Their lifespans are about two and a half to four years in the wild.[10] They have large canine teeth, and also high-crowned cheek teeth similar to those of ungulates.[11] Their dental formula is 1-3.1.4.23.1.4.2-3G
Although mostly diurnal[12] and very active, they are difficult to trap and very seldom seen; elephant shrews are wary, well camouflaged, and adept at dashing away from threats. Several species make a series of cleared pathways through the undergrowth and spend their day patrolling them for insect life. If the animal is disturbed, the pathway provides an obstacle-free escape route.
Elephant shrews are not highly social animals, but many live in monogamous pairs, which share and defend their home territory, marked using scent glands.[11] Rhynchocyon species also dig small conical holes in the soil, bandicoot-style, but others may make use of natural crevices, or make leaf nests.
Short-eared elephant shrews inhabit the dry steppes and stone deserts of southwestern Africa. They can even be found in the Namib Desert, one of the driest regions of the earth. Females drive away other females, while males try to ward off other males. Although they live in pairs, the partners do not care much for each other and their sole purpose of even associating with the opposite sex is for reproduction. Social behaviors are not very common and they even have separate nests. The one or two young are well developed at birth; they are able to run within a few hours.[13]
Female elephant shrews undergo a menstrual cycle similar to that of human females and the species is one of the few nonprimate mammals to do so.[14] Elephant shrews were used in the 1940s to study the human menstruation cycle.[15] The elephant shrew mating period lasts for several days. After mating, the pair will return to their solitary habits. After a gestation period varying from 45 to 60 days, the female will bear litters of one to three young several times a year. The young are born relatively well developed, but remain in the nest for several days before venturing outside.[11]
After five days, the young's milk diet is supplemented with mashed insects, which are collected and transported in the cheek pouches of the female. The young then slowly start to explore their environment and hunt for insects. After about 15 days, the young will begin the migratory phase of their lives, which lessens their dependency on their mother. The young will then establish their own home ranges (about 1 km2 (0.39 sq mi)) and will become sexually active within 41–46 days.[16][17]
The thermal characteristics of elephant shrews with similar body size, habitat and distribution are very close in most of the classifications. They can maintain homeothermy in different ambient temperatures where most of the species regulate their body temperature at 35°C and neither become hyperthermic but they balance the heat offload by increasing the EWL (evaporative water loss).[18]
Elephant shrews mainly eat insects, spiders, centipedes, millipedes, and earthworms. An elephant shrew uses its nose to find prey and uses its tongue to flick small food into its mouth, much like an anteater. Eating large prey can pose a challenge; an elephant shrew struggling with an earthworm must first pin its prey to the ground with a forefoot. Then, turning its head to one side, it chews pieces off with its cheek teeth, much like a dog chewing a bone. This is a sloppy process, and many small pieces of worm drop to the ground; these are simply flicked up with the tongue. Some elephant shrews also feed on small amounts of plant matter, especially new leaves, seeds, and small fruits.[16]
A number of fossil species are known, all from Africa. They were separate from the similar-appearing order Leptictida. A considerable diversification of macroscelids occurred in the Paleogene period. Some, such as Myohyrax, were so similar to hyraxes that they were initially included with that group, while others, such as Mylomygale, were relatively rodent-like. These unusual forms all died out by the Pleistocene.[19] Although macroscelids were classified in the past with many groups, often on the basis of superficial characteristics, considerable morphological and molecular evidence places them within Afrotheria, at the base of Afroinsectivora.[20]
In terms of timing, the divergence between macroscelids and afrosoricidans is thought to have occurred roughly 57.5 million years (Ma) ago, in the late Paleocene, while the diversification of extant macroscelids apparently began when the Rhynchocyon lineage split off about 33 Ma ago, in the early Oligocene.[21] Elephantulus is considered to have separated from Macroscelidini later in the Oligocene, about 28.5 Ma ago.[21]
Macroscelididae
The 20 species of elephant shrew are placed in six genera, three of which are monotypic:
Elephant shrews, also called jumping shrews or sengis, are small insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order Macroscelidea. Their traditional common English name "elephant shrew" comes from a perceived resemblance between their long noses and the trunk of an elephant, and their superficial similarity with shrews (family Soricidae) in the order Eulipotyphla. However, phylogenetic analysis has revealed that elephant shrews are not properly classified with true shrews, but are in fact more closely related to elephants than to shrews. In 1997, the biologist Jonathan Kingdon proposed that they instead be called "sengis" (singular sengi), a term derived from the Bantu languages of Africa, and in 1998, they were classified into the new clade Afrotheria.
R. petersi skeleton, Museum of Osteology Eastern rock elephant shrew, Elephantulus myurus, South Africa Bushveld elephant shrew, E. intufi, Namibia They are widely distributed across the southern part of Africa, and although common nowhere, can be found in almost any type of habitat, from the Namib Desert to boulder-strewn outcrops in South Africa to thick forest. One species, the North African elephant shrew, remains in the semi-arid, mountainous country in the far northwest of Africa. The Somali elephant shrew went unobserved from 1968 to 2020 but was rediscovered by a group of scientists in Djibouti.
_colourised.png){kind=small}
_(Chrysochloris_asiatica).jpg){kind=small}
_(Tenrec_ecaudatus).jpg){kind=small}
.jpg){kind=small}
