Hemicentetes semispinosusstreaked tenrec

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. (Marshall and Eisenberg, 1996)

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. (Goodman, et al., 2000; Marshall and Eisenberg, 1996; Stephenson, 2007)

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). (Marshall and Eisenberg, 1996; Stephenson, 2007; Symonds, 2005)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    125 to 280 g
    4.41 to 9.87 oz
  • Average length
    140 mm
    5.51 in
  • Average basal metabolic rate
    0.38 W
    AnAge

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. (Gould and Eisenberg, 1966; Marshall and Eisenberg, 1996; Stephenson, 2007; Symonds, 2005)

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. (Marshall and Eisenberg, 1996; Stephenson, 2003; Stephenson, 2007)

  • Breeding interval
    Lowland streaked tenrecs usually breed once a year, but can sometimes breed twice within the same season.
  • Breeding season
    Breeding occurs between November and May.
  • Range number of offspring
    1 to 11
  • Average number of offspring
    6.3
  • Average number of offspring
    4
    AnAge
  • Range gestation period
    55 to 58 days
  • Average weaning age
    25 days
  • Average time to independence
    40 days
  • Average age at sexual or reproductive maturity (female)
    25 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    35 days
    AnAge

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. (Gould and Eisenberg, 1966; Marshall and Eisenberg, 1996)

  • Parental Investment
  • 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. (Stephenson, 2007)

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. (Marshall and Eisenberg, 1996; Stephenson and Racey, 1994; Stephenson, 2007; Symonds, 2005)

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. (Marshall and Eisenberg, 1996; Stephenson, 2003; Stephenson, 2007; Symonds, 2005)

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. (Marshall and Eisenberg, 1996; Symonds, 2005)

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. (Marshall and Eisenberg, 1996; Stephenson, 2003; Symonds, 2005)

  • 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. (Marshall and Eisenberg, 1996; Stephenson, 2007)

  • Anti-predator Adaptations
  • 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. (Vavra, et al., 2006)

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. (Harduin, 1995)

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. (Riley and Chomel, 2005)

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 (Gould and Eisenberg, 1966; Marshall and Eisenberg, 1996; Stephenson, 2003; Stephenson, 2007; Symonds, 2005)

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. (Buffenstein and Salton, 2003; Endo, et al., 2006; Marshall and Eisenberg, 1996; Stephenson, 2003)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

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

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.

carnivore

an animal that mainly eats meat

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.

diurnal
  1. active during the day, 2. lasting for one day.
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.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

induced ovulation

ovulation is stimulated by the act of copulation (does not occur spontaneously)

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.

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.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

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

social

associates with others of its species; forms social groups.

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.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

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.

year-round breeding

breeding takes place throughout the year

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. 2003. Hemicentetes, Streaked Tenrecs. Pp. 1281-1283 in S Goodman, J Benstead, eds. 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.

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.

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.