Elephant shrew
Elephant shrew | |
---|---|
Black and rufous elephant shrew, Rhynchocyon petersi, Philadelphia Zoo | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Infraclass: | Placentalia |
Superorder: | Afrotheria |
Grandorder: | Afroinsectiphilia |
Mirorder: | Afroinsectivora |
Order: | Macroscelidea Butler, 1956 |
Family: | Macroscelididae Bonaparte , 1838
|
Type genus | |
Macroscelides A. Smith, 1829
| |
Genera | |
Elephantulus | |
Range map of elephant shrew by genus |
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
Characteristics
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] They are solitary animals which means that they rely on a combination of vocalizations and scent markings for communication with their vocalizations, which serves the purposes such as territory defense and mate attraction.[10]
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
Although mostly diurnal[13] 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,and live in seldom. They share and defend their home territory if another organism were to trespass into their territory they would be violently kicked out, which involves screaming, sparring, snapping and kicking (Simmons, 1991). Marked using scent glands.[12] Rhynchocyon species also dig small conical holes in the soil, bandicoot-style, but others may make use of natural crevices, or make leaf nests. and keep track of each other through scent marking.
Short-eared elephant shrews inhabit the dry steppes and stone deserts of southwestern Africa. They can even be found in the
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.[15] Elephant shrews were used in the 1940s to study the human menstruation cycle.[16] 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.[12]
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.[17][18]
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).[19]
Feeding habits
Elephant shrews mainly eat
Evolution
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.[20] 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.[21]
In terms of timing, the divergence between macroscelids and afrosoricidans is thought to have occurred roughly 57.5 million years (
Phylogeny
| |||||||||||||||||||||
A cladogram of Afrotheria based on molecular evidence[21] |
Cladogram of living elephant shrews[23][22] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Classification
The 20 species of elephant shrew are placed in six
- ORDER MACROSCELIDEA[3]
- Family Macroscelididae
- Genus Elephantulus
- Short-snouted elephant shrew, E. brachyrhynchus
- Cape elephant shrew, E. edwardii
- Dusky-footed elephant shrew, E. fuscipes
- Dusky elephant shrew, E. fuscus
- Bushveld elephant shrew, E. intufi
- Eastern rock elephant shrew, E. myurus
- Karoo rock elephant shrew, E. pilicaudus[24]
- Western rock elephant shrew, E. rupestris
- Genus Galegeeska
- Somali elephant shrew, G. revoilii[22]
- Rufous elephant shrew, G. rufescens[25]
- Genus Macroscelides
- Namib round-eared sengi, M. flavicaudatus
- Etendeka round-eared sengi, M. micus
- Round-eared elephant shrew, M. proboscideus
- Genus Petrodromus
- Four-toed elephant shrew, P. tetradactylus
- Genus Petrosaltator
- North African elephant shrew, P. rozeti
- Genus Rhynchocyon
- Golden-rumped elephant shrew, R. chrysopygus
- Checkered elephant shrew, R. cirnei
- Rhynchocyon cirnei cirnei
- Rhynchocyon cirnei shirensis
- Rhynchocyon cirnei reichardi
- Rhynchocyon cirnei hendersoni
- Rhynchocyon cirnei macrurus
- Black and rufous elephant shrew, R. petersi
- Rhynchocyon petersi petersi
- Rhynchocyon petersi adersi
- Stuhlmann's elephant shrew, R. stuhlmanni[26]
- Grey-faced sengi, R. udzungwensis
- Genus Elephantulus
- Family Macroscelididae
References
- S2CID 128423895.
- ^ Martin Pickford (2015). "Chrysochloridae (Mammalia) from the Lutetian (Middle Eocene) of Black Crow, Namibia" (PDF). Communications of the Geological Survey of Namibia. 16: 105–113.
- ^ OCLC 62265494.
- PMID 15930154.
- ISBN 978-0-691-11692-1.
- PMID 9707584.
- ^ Briggs, Helen (18 August 2020). "Elephant shrew rediscovered in Africa after 50 years". BBC News. Retrieved 19 August 2020.
- ^ Davies, Ella (16 January 2014). "Secrets of the sengi: the world's fastest small mammal". BBC Nature. Archived from the original on 2014-01-16.
- PMID 23516530.
- ISSN 0305-1838.
- ^ Encyclopedia of Animals. Online database: EBSCO Publishing.
- ^ ISBN 978-0-87196-871-5.
- ^ Conniff, Richard. Shrewd Configuration, Smithsonian, June 2005. pp. 26-28.
- ^ "Short-eared elephant-shrew (Macroscelides proboscideus) - A "living fossil" from the Namib-desert". Natur Spot. Archived from the original on 19 July 2011. Retrieved 1 February 2010.
- ^ van der Horst, Cornelius; Gillman, Joseph (1941). "The menstrual cycle in Elephantulus". The South African Journal of Medical Sciences. 6: 27–47.
- S2CID 49414099.
- ^ a b Rathbun, Galen B. (September 1992). "The Fairly True Elephant-Shrew". Natural History. 101. New York.
- ^ Unger, Regina. "Short-eared Elephant-Shrews". Retrieved 1 February 2010.
- .
- ISBN 978-0-8160-1194-0.
- ^ S2CID 46133294. Archived from the original(PDF) on 2021-02-24. Retrieved 2020-08-15.
- ^ PMID 32879790.
- PMID 31800571.
- .
- S2CID 233667864.
- PMID 28552433.
- Murata, Y.; Nikaido, M.; Sasaki, T.; Cao, Y.; Fukumoto, Y.; Hasegawa, M.; Okada, N. (2003). "Afrotherian phylogeny as inferred from complete mitochondrial genomes". Molecular Phylogenetics and Evolution. 28 (2): 253–260. PMID 12878462.
- Murphy, W.J.; Eizirik, E.; Johnson, W.E.; Zhang, Y.P.; Ryder, O.A.; O'Brien, S.J. (2001). "Molecular phylogenetics and the origins of placental mammals". Nature. 409 (6820): 614–618. S2CID 4373847.
- Tabuce, R.; Marivaux, L.; Adaci, M.; Bensalah, M.; Hartenberger, J.-L.; Mahboubi, M.; Mebrouk, F.; Tafforeau, P.; Jaeger, J.-J. (2007). "Early Tertiary mammals from North Africa reinforce the molecular Afrotheria clade". Proceedings of the Royal Society B: Biological Sciences. 274 (1614): 1159–1166. PMID 17329227.
External links
- "Elephant Shrew". African Wildlife Foundation. Retrieved 1 February 2010.
- "Sengis (Elephant-Shrews)". California Academy of Sciences. Archived from the original on 10 May 2013. Retrieved 1 October 2012.
- "New Species Of Giant Elephant-shrew Discovered". Science Daily. February 2008. Retrieved 1 February 2010.
- "New sengi species is related to an elephant, but small as a mouse". Los Angeles Times. June 2014. Retrieved 1 June 2014.