Tenrec ecaudatustailless tenrec

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Geographic Range

The common tenrec occurs on Madagascar and on the Comoro Islands, between Madagascar and Africa. It has been introduced on Reunion, Mauritius, and the Seychelle Islands.

Habitat

Tenrec ecaudatus is generally found near water sources in areas with ample brush and undergrowth for cover. It seems to be equally common in inland plateaus and coastal humid forests throughout Madagascar, but it is absent in the arid southwestern districts. Generally, the common tenrec is found in the eastern rainforests and in the gallery forests that border the river systems of the west. These animals are very common near paddy fields.

Physical Description

Tenrec ecaudatus is one of the largest living insectivores. Head and body length ranges from 265 to 390 mm. The coloration of the common tenrec varies geographically from grey-brown to red-brown. Pelage is not dense and is a combination of hairs and blunt spines. The young have rows of white spines in longitudinal rows along their backs; these are replaced in the adult by a mane of stiff long hairs. The forelimbs are longer than the hindlimbs. The skull is cylindrical and the snout elongated. Females generally have 12 nipples, but up to 29 have been recorded.

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    1.6 to 2.4 kg
    3.52 to 5.29 lb
  • Range length
    265 to 390 mm
    10.43 to 15.35 in
  • Average basal metabolic rate
    0.729 W
    AnAge

Reproduction

Common tenrecs are usually solitary, but during the austral breeding season (October to November) male-female encounters often lead to brief physical contact (i.e. nose-to-rump, nose-to-nose, nose-to-side, nose-to-cloaca, nose-to-ear) and then mating. The male often licks the female and grasps her with his forelimbs to copulate.

Gestation lasts 56 to 64 days. Young are born in the wet months of December and January, when the number of invertebrates is at a maximum. It is thought that only one litter per year is usual, but the presence of small young in March suggests that a second litter is possible if the first litter dies after birth. Litter size ranges from 1 to 32, the extreme for mammals. The average litter size varies with habitat type; average size is 10 in the Seychelles rainforests near the equator, 15 in most rainforest areas examined, and 20 in seasonal woodland and savanna regions.

  • Breeding interval
    It is thought that only one litter per year is usual, but the presence of small young in March suggests that a second litter is possible if the first litter dies after birth.
  • Breeding season
    Breeding occurs in October and November.
  • Range number of offspring
    1 to 32
  • Average number of offspring
    18
    AnAge
  • Range gestation period
    56 to 64 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    182 days
    AnAge

At birth the young are fairly undeveloped, but are less altricial than the newly born young of most insectivores. Their eyes open between 9 and 14 days. At three weeks the young begin to forage with their mother, following her in a more-or-less straight line. Like their mother, they gather and carry nest materials in their mouths. They begin to nurse less and to take solid food at approximately four weeks. The young molt their characteristic stripes at 36 days, and leave the nest shortly after. They often forage together for a period after dispersing from the nest.

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

A captive common tenrec lived for 59 months.

Behavior

The common tenrec is a solitary animal and attempts to avoid conspecifics; with the exception of mother and young. Tenrec ecaudatus forages and hibernates alone. Males that meet during the breeding season will fight one another. Common tenrecs have two major daily activity periods, the first from 1800 to 2100 hours and the second from 0100 to 0500 hours. It is not unusual to see tenrecs swimming in rice paddies during their forays. They will climb steep rock faces when seeking food, but it is uncommon to see them in trees.

The burrows of the common tenrec are usually near streams and are of two distict types. A hibernating burrow is between one and two meters long. The single entrance is plugged with soil during the period of torpor. The burrows of active common tenrecs are quite different; a Y-shaped opening provides two open exit routes. The burrows serve the animals as buffers to extreme temperatures. Tenrecs hibernate during the dry autumn months of May through September, when resources are limited. During this period of torpor, their bodies are cold to the touch.

Home Range

These animals cover 0.5 to 2 hectares per night in search of food. Receptive females, however, range over only around 200 square meters; it has been hypothesized that decreasing the foraging range may increase the likelihood of being found by a male.

Communication and Perception

When threatened or angered the common tenrec erects the ridge of long hairs on its back and vocalizes with hisses, squeaks, squeals, and "piff" sounds. If an animal is surprised in its nest it will display its truly enormous gape. If startled in the open it can run quickly to cover. Disturbed young tenrecs produce an audible alarm signal through a process called stridulation, in which bristles on the midback are rubbed together. Hearing this sound may cause littermates to scatter and run. Stridulation may also help the young to locate one another or the mother to locate her young.

One of the most important of the common tenrec's senses may be the long whiskers and the sensitive hairs on the back; these are used to detect vibrations. The common tenrec's eyesight is better than that of most tenrecids and may also be an important sense. In addition, observations of captive T. ecaudatus scent-marking by dragging its cloaca on the ground indicate that scent is an important form of communication in these animals.

Food Habits

Tenrec ecaudatus is omnivorous and eats some vegetation, fruit, reptiles, amphibians, and small mammals in addition to its main diet of invertebrates. These tenrecs probe fissures in rocks and logs with the snout and detect prey with long, sensitive whiskers. They capture and kill with the mouth.

  • Animal Foods
  • mammals
  • amphibians
  • reptiles
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • fruit

Predation

Increased energy requirements during lactation necessitate feeding during daylight hours. It is thought that the stripes of the young and the dark coloration of the female function in camouflaging them during daytime foraging.

  • Anti-predator Adaptations
  • cryptic

Economic Importance for Humans: Positive

The common tenrec has been an important food source for the human inhabitants of Madagascar for thousands of years. In addition, as an insectivore it undoubtedly reduces the numbers of insect pests.

Conservation Status

This species is reported to be common on Madagascar, and is not generally believed to be in need of special conservation efforts. Introduced rats (genus Rattus) may compete with the common tenrec in some circumstances. The IUCN rates the species as being of "Least Concern," it's lowest category, and the species is not listed in the CITES treaty.

Contributors

Antonia Gorog (author), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Eisenberg, J.F. and Gould, Edwin. (1970). The Tenrecs: A Study in Mammalian Behavior and Evolution, Smithsonian Institution Press, Washington, D.C.

Macdonald, David. (1984). The Encyclopedia of Mammals, Facts on File Publicatons, New York.

Nowak, Ronald M. and Paradiso, John L. (1983). Walker's Mammals of the World, The Johns Hopkins University Press, Baltimore and London.