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.
Known Predators:
Anti-predator Adaptations: cryptic
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).
Range mass: 125 to 280 g.
Average length: 140 mm.
Sexual Dimorphism: sexes alike
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.38 W.
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.
Range lifespan
Status: captivity: 30 (high) months.
Average lifespan
Status: captivity: 2.6 years.
Average lifespan
Status: wild: 2.7 years.
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 ; terrestrial
Terrestrial Biomes: rainforest
Other Habitat Features: agricultural
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 (Native )
Other Geographic Terms: island endemic
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.
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 ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; ultrasound ; chemical
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.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
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.
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.
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.
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.
Animal Foods: insects; terrestrial non-insect arthropods; terrestrial worms
Primary Diet: carnivore (Vermivore)
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.
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.
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.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; viviparous
Average birth mass: 11.5 g.
Average number of offspring: 4.
Average age at sexual or reproductive maturity (female)
Sex: female: 35 days.
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 ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female)
The lowland streaked tenrec (Hemicentetes semispinosus) is a small tenrec found in Madagascar. It belongs to the family Tenrecidae in the order Afrosoricida, and more specifically to the subfamily of the spiny tenrecs Tenrecinae.[3] Its natural habitats are in tropical lowland rain forests in northern and eastern parts of Madagascar.
It is very closely related to the Highland streaked tenrec.
It can be found on land, splashing in shallow waters or digging underground.
The average body size for H. semispinosus is a length of 140 mm (5.5 in) however adults have been recorded to grow up to a maximum of 172 mm (6.8 in). Body weight for adults of this species can range from 125 to 280 g (4.4 to 9.9 oz).[4] This species has a black spiny pelage with yellow or chestnut-brown stripes that run the length of the body.[4][3] There is a median yellow stripe that runs down the rostrum along with one dorsal and two lateral stripes that mark the length of the body and may serve as a warning to predators. Quills are present in this species being longer and more numerous on the head and nuchal area. However, the ventral region contains few to no quills but have the ability to detach in predation defense.[4]
H. semispinosus possesses sensory hairs that are scattered on the dorsum that are similar to vibrissae.[4] It has an evolutionary adaptation for its semifossorial habits with a well developed lateral and long heads of M. triceps brachii and enlarged M. teres major that function as an extensor of the elbow joint and as an adductor of the upper arm for digging. This species also has elongated hands and second, third, and fourth digit adaptation that acts as the main fossorial adaptation.[3] The middle of the skull of this species is long and low, the alveolar processes of the maxilla, premaxilla and mandible are reduced and the palate narrow. The teeth are small, spaced, and placed farther forward on the skull. The temporal muscles, sagittal, and nuchal crests are weaker compared to other tenrec species.[5]
In addition, the lowland streaked tenrec has been found to have thermolability, which depends on factors such as habitat and temperature.[6]
These tenrecs are threatened primarily by the loss of their natural habitat due to continuous deforestation, as it is with many other animals in the Madagascar region. This species is also being hunted for food.[7]
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. The Streaked tenrec will flaunt its quails to scare away any possible predators. When forced to engage another species it will use a rough headbutt in an attempt to immobilize its target.
The lowland streaked tenrec is active both during the day and at night. Its diet is made up primarily of earthworms, but it will sometimes prey on other invertebrates as well. It may be seen stamping its feet on the ground with its fore-paws, an adaptation which is believed to increase earthworm activity for easier foraging.[8] Most tenrecs possess a long snout for poking around in the ground to find their food. They are also capable of eating fruit. While the streaked tenrec does eat earthworms, the dirt may corrode their teeth with scratches and pits.[9]
Breeding takes place during October to December and possibly at other times, depending upon local food supply and temperature. The gestation period lasts 58 days, and the female gives birth to usually between 5 and 8 young. The young are weaned at 18 to 25 days. These tenrecs on average retain the ability to conceive at about 35 days.[10] They have the ability to reproduce during the same season they were produced.[10]
The streaked tenrec lives in long, shallow burrows which are usually occupied by family groups.
H. semispinosus has hard keratinous quills located in the mid-dorsal region that act as a sounding device and are thought to be used for communication between mother and young and/or a warning signal to predators.[4][11] Movement of these quills causes the tips to rub together and create a high frequency sound.[4] These quills are located in a small area of the mid-dorsal region in a group of seven to sixteen arranged in three rows.[4][11] Five quills run laterally on each side and is flanked by five to six quills being light brown in color. The arrangement and number of quills does not alter during growth and neither does the length. The circumference of the quills however, does change from juvenile to adult.[11]
When an individual is aggravated a defense response is produced by erecting its quills laterally and forward which produces sound when the quills vibrate.[4][3] H. semispinosus has a highly developed sense of smell and this response along with foot stamping is also produced when the odor of a predator is detected.[4][12] This display additionally occurs when males fight for females and when unfamiliar males come across one another. Female encounters however, have tactile contact and then increase the distance between each other.[4] It uses its quills to communicate in two different ways, by raising them in agitation or by rubbing them together in a method known as stridulation – best known as the type noise produced by crickets and cicadas. The sound produced is too high to be perceived by human ears.[12]
The streaked tenrec is the only mammal known to use stridulation for generating sound, a method more commonly associated with insects and snakes.[13][14] Due to its rarity, there is not sufficient information regarding the functional-morphological mechanism of the streaked tenrec. The sounding quills are different from the spines and hair and are found in the mid-dorsal region of the streaked tenrec. The arrangement and length are similar throughout the streaked tenrec's life span, making up three rows in its midline area and adjacent areas bilaterally.[11] Cutaneous muscles underneath the quills were confirmed and are known as quill vibrator disc; they are around 16.8 mm long and 8.55 mm in width for an adult. These cutaneous muscles were the apparatus that contribute the vibration of the quills and production of sound for communication.[11][15]
The streaked tenrec has an ability to enter torpor seasonally. However, it is dependent on altitude, age, fat stores, and temperature. Torpor for this species generally occurs during June and July and during winter. However, H. semispinosus is a facultative hibernator and will come out of torpor during winter and forage. When foraging the soil and leaf litter is prodded with the tip of the nose until prey is detected.[4] Elongated hands and digit adaptation (digits 2, 3, and 4) are the tenrec's main digging apparatus allowing it to unearth and pull its prey form the earth.[3]
The skull has an elongated rostrum with a slender jaw with small spaced dentition placed more forward in the mouth.[4][5] This species has zalambdodont molars with a dental formula of I 3/3, C 1/1, P 3/3, M 3/3 having a total of 40 teeth.[4] The sagittal crest and nuchal are less prominent in this species and the zygomatic processes are long and slender resulting in less projection from the sides of the skull.[4][5] The occipital region in this species along with the visceral skeleton are commonly very conservative.[12]
The lowland streaked tenrec (Hemicentetes semispinosus) is a small tenrec found in Madagascar. It belongs to the family Tenrecidae in the order Afrosoricida, and more specifically to the subfamily of the spiny tenrecs Tenrecinae. Its natural habitats are in tropical lowland rain forests in northern and eastern parts of Madagascar.
It is very closely related to the Highland streaked tenrec.
