Hemicentetes semispinosus
streaked tenrec

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)

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)

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)

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)

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.

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)

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)

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)

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)

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)

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)

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.

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)