Hemicentetes semispinosus

Geographic Range

There are two species in the genus Hemicentetes , H. semispinosus and H. nigriceps ; both are found only on Madagascar. Lowland streaked tenrecs ( H. semispinosus ) are found in the rainforests on the east side of the island and highland streaked tenrecs ( H. nigriceps ) are found in humid forest and plateau savanna boundary habitat in the central upland portion of Madagascar.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Lowland streaked tenrecs ( H. semispinosus ) are found in tropical rainforest habitats while highland streaked tenrecs ( H. nigriceps ) are found in both tropical rainforest and savanna habitats. Their ranges were not thought to overlap, but they were found coexisting in the widely varied habitat of Mahatsinjo Forest in 2000, which led researchers to believe that they were separate species rather than subspecies.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

• Other Habitat Features
• agricultural agricultural

Physical Description

Lowland streaked tenrecs ( H. semispinosus ) have black and yellow quills covering their bodies and have four primary longitudinal yellow stripes. One of these yellow stripes is found down the median of the rostrum and the other three are found on the body. Of the stripes found on the body, two are found down the middle of the sides and the third is found down the middle of the dorsum. Highland streaked tenrecs ( H. nigriceps ) have black and white quills and have a similar striped pattern, but there is no stripe on the rostrum. The function of the black and white pattern may be to mimic juvenile Tenrec ecaudatus since the parents of this species are known to be aggressively protective. The striping patterns of both species may have developed as a type of camouflage while foraging. Both species have barbed detachable quills to use as a defense mechanism; these quills cover a woolly underfur. A stridulation organ consisting of several of these quills is also present, and when the quills are rubbed together they emit a high-pitched sound which is hypothesized to be a source of communication among individuals. A tail is absent in both species, and body lengths average 140 mm. Body weights range from 80 to 150 g in highland streaked tenrecs ( H. nigriceps ), making them slightly smaller than lowland streaked tenrecs, whose body weight ranges from 125 to 280 g. A cloaca is present for reproduction, urination, and defecation, and both species have zalambdodont molars. The spinal columns include an unusually large number of lumbar vertebrae (20 to 21 vertebrae).

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Females will also erect their quills toward a male if they are not reproductively receptive and will stick spines in the male’s genitals; males have been known to fight among one another if females are present. During courtship the male approaches the female hissing with his snout in the air. If accepted, the male will then nose the female around the neck area followed by nosing her in the cloaca while the female then grabs his snout with her jaws.

Copulation occurs during Madagascar’s rainy season between November and May for both Hemicentetes species and ovulation only occurs after copulation. If winter conditions are absent, breeding can potentially occur year-round. However, females are only fertile up to a year after they are born. Average gestation takes 55 to 58 days. The average litter size is 6.3 for lowland streaked tenrecs ( H. semispinosus ) and 1.3 for highland streaked tenrecs ( H. nigriceps ). Litter size increases in captivity for both species. Lowland streaked tenrecs have as many as 11 offspring in captivity and highland streaked tenrecs have given birth to a maximum of 4. Young streaked tenrecs weigh about 11 g and are 55 to 67 mm in length. By day 25, both species are weaned; adulthood is reached by day 40 (maturity in other spiny tenrec species [ Setifer setsosus and Echinops telfairi ] doesn’t occur for 6 months). Females can be reproductively active by day 25 in lowland streaked tenrecs; they may be the only tenrec that can breed in the same season in which they were born. They have an elevated resting metabolic rate during reproduction.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• induced ovulation induced ovulation
• viviparous viviparous

Most information on parental care in streaked tenrecs is based on captive animals. In preparation for birth, a pregnant female will use her snout as a spade to clear away a depression in the ground within the burrow. When the young are born, the female will help clear away tissue from the snout area so that they are able to breathe. The male will help protect the young by allowing them to huddle around him. The female takes care of both cleaning and replacing the lining in the nest. If the offspring wander too far from the nest, females will carry them back to the nest. Mothers maintain contact with their offspring while foraging by using both smell and the stridulation organ after the stridulation organ starts working in the young. Offspring are born without spines, but begin to develop them within the first 24 hours of life.

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

Lifespan/Longevity

Lowland streaked tenrecs ( Hemicentetes semispinosus ) live as long as 30 months in captivity and highland streaked tenrecs ( H. nigriceps ) up to 3 years. How long either species lives in the wild is unknown.

Behavior

Both Hemicentetes species go into torpor, with a higher likelihood of entering the torpor phase in captivity than in the wild. Lowland streaked tenrecs ( H. semispinosus ) are more likely to come out of torpor during the winter season for foraging than are highland streaked tenrecs ( H. nigriceps ). Interrupting torpor may actually increase the productivity of lowland streaked tenrecs. Highland streaked tenrecs focus on nocturnal activity while lowland streaked tenrecs are mainly active throughout the day. Burrows of lowland streaked tenrecs occur in primary or secondary forests and may be occupied by either one individual or as many as 23 during the breeding season. Highland streaked tenrecs make shallower burrows than lowland streaked tenrecs on forest fringes and near cultivated fields. A leaf plug seals the hole of both species’ burrows. Burrows are likely used to help thermoregulate and to avoid predators.

• Key Behaviors
• terricolous
• fossorial fossorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• social social

Home Range

Home range sizes of streaked tenrecs are not reported in the literature.

Communication and Perception

These tenrecs erect spines on the head while moving the head up and down repetitively if the animal is disturbed. This is how an animal can impale a potential enemy or predator with quills. If a disturbance continues, stamping of the forefeet may occur as well as rushing at the disturbance; even bright light has been known to bring on these reactions. Males may fight over females by biting each other, head-butting, or grappling, but they are generally docile. Head-butting is extremely useful during scuffles over mates due to an enlarged frontalis muscle on the forehead that increases mobility of the facial spines. Females also are non-aggressive and usually just try to avoid each other. Nose-touching is a common mode of interaction between individuals. When introduced to a new location, streaked tenrecs repeatedly use an explicit area as a latrine and will sometimes mark new burrows with feces.

A stridulation organ consisting of 7 to 16 specialized spines is found in both species ( H. semispinosus and H. nigriceps ). When the tips of these spines are rubbed together rapidly they produce high-frequency sounds that are thought to allow communication between members of foraging groups. These sounds might also be used as a predator warning device. Tongue clicks are used as well and may be a possible means of echolocation, but further studies should be conducted to see whether or not true echolocation is used. Chattering and/or squeaking sounds are emitted when the animal is disturbed which sometimes occurs with a low buzzing which happens when quills begin to rise as a reaction to being upset. Scent-marking has also been observed to mark territories in some individuals.

• Communication Channels
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• ultrasound ultrasound
• chemical chemical

Food Habits

Streaked tenrecs ( H. semispinosus and H. nigriceps ) are almost exclusively vermivorous (worm-eating), but other available invertebrates may also be eaten. They sometimes stamp on the ground with the forepaws, which may increase earthworm activity. Foraging in highland streaked tenrecs ( H. nigriceps ) seems to occur especially in or around rice paddies and manioc fields.

• Primary Diet
• carnivore carnivore
  • vermivore

• Animal Foods
• insects
• terrestrial non-insect arthropods
• terrestrial worms

Predation

Both species ( H. semispinosus and H. nigriceps ) are the natural prey of Dumeril's boas ( Acrantophis dumerilli ), Malagasy ring-tailed mongooses ( Galidia elegans ), Malagasy fossas ( Cryptoprocta ferox ) and Malagasy civets ( Fossa fossana ). Humans have also been known to capture and kill streaked tenrecs, both by hand and with dogs (pers. obs.). Streaked tenrecs are cryptically colored and vigilant to avoid being noticed by predators. Their spines and use of burrows also helps to protect them from predation.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Streaked tenrecs are important as predators of worms in their native Malagasy habitats. A lesion on a lowland streaked tenrec individual led to the discovery of a new species of microsporidian fungi.

Economic Importance for Humans: Positive

Other tenrecs such as Setifer setosus and Tenrec ecaudatus have been proposed to be raised as ‘mini-livestock’ for human consumption, so it is possible that both highland ( H. semispinosus ) and lowland streaked tenrecs ( H. nigriceps ) could be looked upon as an exotic game meat.

Economic Importance for Humans: Negative

Highland streaked tenrecs ( H. nigriceps ) are known to harbor antibodies for bubonic plague, so it seems likely that lowland streaked tenrecs ( H. semispinosus ) might also have these antibodies and could be a potential carrier.

Conservation Status

Hemicentetes semispinosus is listed as a species of least concern by IUCN due to their widespread distribution, high abundance, and high tolerance to areas with a high abundance of humans. Hemicentetes semispinosus also occurs in numerous protected reserves and national parks.

Other Comments

Hemicentetes nigriceps was once considered a subspecies of Hemicentetes semispinosus . While many authors now recognize that they are separate species, some authors still believe H. nigriceps to be a subspecies

Both highland ( H. nigriceps ) and lowland ( H. semspinosus ) streaked tenrecs have 38 chromosomes. Pit fall traps are commonly used to catch both species. Lowland streaked tenrecs are also missing the 3rd trochanter on the hindlimbs and have a larger teres major muscle on the upper back than other tenrecs. Both streaked tenrec species also have extremely low resting metabolic rates compared to similar sized eutherians.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Katie Kokx (author), University of Alaska Fairbanks, Link E. Olson (editor, instructor), University of Alaska Fairbanks.

References

Buffenstein, R., J. Salton. 2003. Field thermoregulatory profiles in tenrecs from the rainforest and dry forest of Madagascar. Integrative and Comparative Biology , 43: 1041.

Endo, H., T. Yonezawa, F. Rakotondraparany, M. Sasaki, M. Hasegawa. 2006. The adaptational strategies of the hindlimb muscles in the Tenrecidae species including the aquatic web-footed tenrec (Limnogale mergulus). Annals of Anatomy , 188: 383-390.

Goodman, S., J. Duchemin, J. Duplantier, D. Rakotondravony, V. Soarimalala. 2000. Syntopic occurrence of Hemicentetes semispinosus and H. nigriceps (Lipotyphla: Tenrecidae) on the Central Highlands of Madagascar. Mammalia , 64: 113-116.

Gould, E., J. Eisenberg. 1966. Notes on the biology of the Tenrecidae. Journal of Mammalogy , 47: 660-686.

Harduin, J. 1995. Minilivestock: from gathering to controlled production. Biodiversity and Conservation , 4: 220-232.

Marshall, C., J. Eisenberg. 1996. Hemicentetes semispinosus. The American Society of Mammalogists, 541: 1-4.

Riley, P., B. Chomel. 2005. Hedgehog zoonoses. Emerging Infectious Diseases , 11: 1-5.

Stephenson, P., P. Racey. 1994. Seasonal variation in resting metabolic rate and body temperature of streaked tenrecs, Hemicentetes nigriceps and H. semispinosus (Insectivora: Tenrecidae). Journal of Zoology , 232: 285-294.

Stephenson, P. 2003. Hemicentetes, Streaked Tenrecs. Pp. 1281-1283 in The Natural History of Madagascar . Chicago and London: University of Chicago Press.

Stephenson, P. 2007. Species profile: streaked tenrecs, Hemicentetes. Afrotherian Conservation Newsletter , 5: 1-3.

Symonds, M. 2005. Phylogeny and life histories of the ‘Insectivora’: controversies and consequences. Biological Reviews , 80: 93-128.

Vavra, J., A. Horak, D. Modry, J. Lukes, E. Koudela. 2006. Trachipleistophora extenrec n. sp. a new microsporidian (Fungi : Microsporidia) infecting mammals. Journal of Eukaryotic Microbiology , 53: 464-476.