A tenrec () is a

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

belonging to any species within the

afrotheria Afrotheria ( from Latin ''Afro-'' "of Africa" + ''theria'' "wild beast") is a superorder of placental mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephan ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Tenrecidae, which is endemic to

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. Tenrecs are a very diverse group, as a result of adaptive radiation, and exhibit

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

, some resemble

hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are 17 species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. The ...

shrew Shrews ( family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to dif ...

opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North A ...

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

s, and

mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

. They occupy aquatic,

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

, and

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

environments. Some of these species, including the greater hedgehog tenrec, can be found in the

Madagascar dry deciduous forests The Madagascar dry deciduous forests represent a tropical and subtropical dry broadleaf forests, tropical dry forest ecoregion situated in the western and northern part of Madagascar. The area has high numbers of Endemism, endemic plant and anima ...

. However, the speciation rate in this group has been higher in humid forests. All tenrecs are believed to descend from a common ancestor that lived 29–37 million years ago after

rafting Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...

over from

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. The split from their closest relatives, African

otter shrew Potamogalidae is the family of "otter shrews", a group of semiaquatic riverine afrotherian mammals indigenous to sub-Saharan Africa. They are most closely related to the tenrecs of Madagascar, from which they are thought to have split about 47� ...

s, is estimated to have occurred about 47–53 million years ago.

Etymology

The word "tenrec" is borrowed, via French, from the Malagasy word (variant of ), which refers to the tailless tenrec (''Tenrec ecaudatus''); the Malagasy word may be related to .

Evolution

Tenrecs are believed to have evolved from a single species that colonized Madagascar between 42 and 25 million years ago. The question of how this family reached Madagascar is still unresolved, but the leading hypothesis suggests a small number of individuals may have found themselves on floating vegetation and crossed the

Mozambique Channel The Mozambique Channel (, , ) is an arm of the Indian Ocean located between the Southeast African countries of Madagascar and Mozambique. The channel is about long and across at its narrowest point, and reaches a depth of about off the coa ...

, which separates Madagascar from southeastern Africa. The Tenrecidae family is one of only four extant terrestrial mammal lineages to have colonized and diversified on Madagascar. Once established on Madagascar, tenrecs diversified to occupy various niches on the island. Many evolved resemblances to familiar but unrelated mammals that are not found on Madagascar. For instance, the two species of hedgehog tenrec possess coats of hardened spines and the ability to roll into a ball when threatened, characteristics similar to those of true

s. This example, along with others, demonstrates convergent evolution; it has provided evolutionary biologists with opportunities to study adaptation over evolutionary timescales.

Characteristics

Tenrecs are small mammals of variable body form. The smallest species are the size of shrews, with a body length of around , and weighing just , while the largest, the common or tailless tenrec, is in length, and can weigh over . Although they may resemble shrews, hedgehogs, or opossums, they are not closely related to any of these groups, their closest relatives being the

s, and after that other African insectivorous mammals including

golden mole Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family Chrysochloridae (the only family in the suborder Chrysochloridea) and as such they are taxonomically distinct from the true moles, f ...

s and

elephant shrew Elephant shrews, also called jumping shrews or sengis, are small insectivore, insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order (biology), order Macroscelidea. Their traditional common English name "ele ...

s. The common ancestry of these animals, which are classified together in the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

Afrotheria Afrotheria ( from Latin ''Afro-'' "of Africa" + ''theria'' "wild beast") is a superorder of placental mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephan ...

, was not recognized until the late 1990s. Continuing work on the molecular and morphological diversity of afrotherian mammals has provided ever increasing support for their common ancestry. Tenrecs are among the few terrestrial mammals that echolocate. Unusual among

placental mammal Placental mammals ( infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguish ...

s, the

rectum The rectum (: rectums or recta) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. Before expulsion through the anus or cloaca, the rectum stores the feces temporarily. The adult ...

and

urogenital tract The genitourinary system, or urogenital system, are the sex organs of the reproductive system and the organ (biology), organs of the urinary system. These are grouped together because of their proximity to each other, Development of the urinary a ...

s of tenrecs share a common opening, or

cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...

which is a feature more commonly seen in

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

s, and

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s. They have a low

body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

, sufficiently low that they do not require a

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

to cool their

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

as do most other mammals. All species appear to be at least somewhat

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

, with

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s forming the largest part of their diets. One species, ''Microgale mergulus'', is

semiaquatic In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water (in ...

(similar to the lifestyle of their closest relatives, the otter shrews). All of the species, semiaquatic or not, appear to have evolved from a single, common ancestor with the otter shrews comprising the next, most-closely related mammalian species. While the fossil record of tenrecs is scarce, at least some specimens from the early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

of Kenya show close affinities to living species from Madagascar, such as ''Geogale aurita''. Most species are

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

and have poor eyesight. Their other senses are well developed, however and they have especially sensitive

whiskers Whiskers, also known as vibrissae (; vibrissa; ) are a type of stiff, functional hair used by most therian mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser as ta ...

. As with many of their other features, the

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

of tenrecs varies greatly between species; they can have from 32 to 42 teeth in total. Unusual for mammals, the permanent dentition in tenrecs tends not to completely erupt until well after adult body size has been reached. This is one of several anatomical features shared by elephants,

hyrax Hyraxes (), also called dassies, are small, stout, thickset, herbivorous mammals in the family Procaviidae within the order Hyracoidea. Hyraxes are well-furred, rotund animals with short tails. Modern hyraxes are typically between in length a ...

es, sengis, and

s (but apparently not

aardvark Aardvarks ( ; ''Orycteropus afer'') are medium-sized, burrowing, nocturnal mammals native to Africa. Aardvarks are the only living species of the family Orycteropodidae and the order Tubulidentata. They have a long proboscis, similar to a pi ...

s), consistent with their descent from a common ancestor. Tenrecs have a

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...

period of 50 to 64 days, and give birth to a number of relatively undeveloped young. While the

s have just two young per litter, the tailless tenrec can have as many as 32, and females possess up to 29

teat A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young. In many mammals, the teat projects from the udder. The number of teats varies by mammalian species and often corr ...

s, more than any other mammal. Some tenrec species are social, living in multigenerational family groups with over a dozen individuals.

Interaction with humans

In the island nation of

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

, and also on the Comoran island of

Mayotte Mayotte ( ; , ; , ; , ), officially the Department of Mayotte (), is an Overseas France, overseas Overseas departments and regions of France, department and region and single territorial collectivity of France. It is one of the Overseas departm ...

, some of the inhabitants eat tenrec meat, although it is difficult to obtain (as it is not sold in shops or markets) and difficult to prepare correctly. The lesser hedgehog tenrec (''Echinops telfairi'') is one of 16 mammalian species that will have its genome sequenced as part of the Mammalian Genome Project. It is increasingly popular in the pet trade, and in the future may serve as an important model organism in biomedicine, as it is only distantly related to the mice, rats, guinea pigs, and rhesus macaques which comprise the most common research animals.

Threats

Of the 31 species assessed, 24 (77%) are categorized by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

as least concern, one species as data deficient, four species as vulnerable, and two species as endangered. The conservation status of many tenrec species is of concern due to an increase of threats within the last 50 years. The main threats facing them include habitat loss due to

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

, fragmentation, and degradation; hunting; incidental capture; and

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

Slash-and-burn Slash-and-burn agriculture is a form of shifting cultivation that involves the cutting and burning of plants in a forest or woodland to create a Field (agriculture), field called a swidden. The method begins by cutting down the trees and woody p ...

agriculture, commercial logging, and mining of metals are negatively affecting tenrec species that inhabit forests. Five of the six threatened tenrec species are dependent on forest habitats.

Conservation

As of 2022, conservation of the tenrec population is not being prioritized. Because most tenrecs are dependent on forest habitats, conservation efforts would need to include a focus on reduction in deforestation on Madagascar, as well as habitat restoration. Current conservation efforts include that of the Madagascar Ankizy Fund, started by a paleontological team from

Stony Brook University Stony Brook University (SBU), officially the State University of New York at Stony Brook, is a public university, public research university in Stony Brook, New York, United States, on Long Island. Along with the University at Buffalo, it is on ...

, to improve access to health care and education facilities for villagers in remote areas of Madagascar. A healthy and educated local human population, in the long term, will benefit the Malagasy fauna, such as tenrecs.

Species

The three subfamilies, eight genera, and 31 extant species of tenrecs are: FAMILY TENRECIDAE * Subfamily Geogalinae ** Genus '' Geogale'' *** Large-eared tenrec (''Geogale aurita'') * Subfamily Oryzorictinae ** Genus '' Microgale'' *** Short-tailed shrew tenrec (''Microgale brevicaudata'') *** Cowan's shrew tenrec (''Microgale cowani'') *** Drouhard's shrew tenrec (''Microgale drouhardi'') *** Dryad shrew tenrec (''Microgale dryas'') *** Pale shrew tenrec (''Microgale fotsifotsy'') *** Gracile shrew tenrec (''Microgale gracilis'') *** Grandidier's shrew tenrec ''(Microgale grandidieri)'' ***

Naked-nosed shrew tenrec The naked-nosed shrew tenrec (''Microgale gymnorhyncha'') is a species of mammal in the family Tenrecidae. It is endemic to Madagascar. Its natural habitats are subtropical and tropical subtropical or tropical moist lowland forest, moist lowland ...

(''Microgale gymnorhyncha'') *** Jenkins's shrew tenrec (''Microgale jenkinsae'') *** Northern shrew tenrec (''Microgale jobihely'') *** Lesser long-tailed shrew tenrec (''Microgale longicaudata'') *** '' Microgale macpheei'' (extinct) *** Major's long-tailed tenrec (''Microgale majori'') *** Web-footed tenrec (''Microgale mergulus'') *** Montane shrew tenrec (''Microgale monticola'') *** Nasolo's shrew tenrec (''Microgale nasoloi'') *** Pygmy shrew tenrec (''Microgale parvula'') *** Greater long-tailed shrew tenrec (''Microgale principula'') *** Least shrew tenrec (''Microgale pusilla'') *** Shrew-toothed shrew tenrec (''Microgale soricoides'') *** Taiva shrew tenrec (''Microgale taiva'') *** Thomas's shrew tenrec (''Microgale thomasi'') ** Genus '' Nesogale'' *** Dobson's shrew tenrec (''Nesogale dobsoni'') *** Talazac's shrew tenrec (''Nesogale talazaci'') ** Genus '' Oryzorictes'' *** Mole-like rice tenrec (''Oryzorictes hova'') *** Four-toed rice tenrec (''Oryzorictes tetradactylus'') * Subfamily

Tenrecinae Tenrecinae is a Tenrecidae, tenrec subfamily endemic to the island of Madagascar. It contains the largest species in the family, ''Tenrec ecaudatus''. All members of the genus possess Spine (zoology), spines, analogous to those of hedgehogs, for ...

** Tribe Setiferini *** Genus '' Echinops'' **** Lesser hedgehog tenrec (''Echinops telfairi'') *** Genus '' Setifer'' **** Greater hedgehog tenrec (''Setifer setosus'') ** Tribe Tenrecini *** Genus '' Hemicentetes'' **** Highland streaked tenrec (''Hemicentetes nigriceps'') **** Lowland streaked tenrec (''Hemicentetes semispinosus'') *** Genus ''

Tenrec A tenrec () is a mammal belonging to any species within the afrotherian family Tenrecidae, which is endemic to Madagascar. Tenrecs are a very diverse group, as a result of adaptive radiation, and exhibit convergent evolution, some resemble hed ...

'' **** Common tenrec (''Tenrec ecaudatus'')

References

External links

Bizarre mammals filmed calling using their quills
at BBC Online, video with commentary by Sir

David Attenborough Sir David Frederick Attenborough (; born 8 May 1926) is an English broadcaster, biologist, natural historian and writer. He is best known for writing and presenting, in conjunction with the BBC Studios Natural History Unit, the nine nature d ...

*
Podcast about hibernation which focusses on tenrecs in the last third.
{{Authority control Afrosoricida Endemic fauna of Madagascar Mammals of Madagascar Extant Eocene first appearances Animals that use echolocation Taxa named by John Edward Gray