Animal Diversity Web

Ge­o­graphic Range

Tree shrew ten­recs, Mi­cro­gale dryas, have only been found at the Am­bat­o­vaky Spe­cial Re­serve in north-east­ern Mada­gas­car. Am­bat­o­vaky is a na­ture re­serve lo­cated 50km west of the town Soanier­ana-Ivongo on the east­ern coast of Mada­gas­car. ("In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources", 2003; Crow­ley, 2001; Gar­butt, 1999)

• Biogeographic Regions
• ethiopian
  • native

• Other Geographic Terms
• island endemic

Habi­tat

M. dryas lives only in the trop­i­cal rain­for­est of north-east­ern Mada­gas­car. This re­gion in­cludes dense veg­e­ta­tion (mainly ever­green forests). The area is char­ac­ter­ized hav­ing sharp-peaked moun­tains and some aquatic el­e­ments be­cause of the pres­ence of two rel­a­tively large rivers. M. dryas is solely ter­res­trial and oc­cu­pies this dense habi­tat. (Crow­ley, 2001; Gar­butt, 1999; Good­man and Ben­stead, 2004)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• rainforest
• mountains

• Range elevation

  0 to 2300 m

  0.00 to 7545.93 ft

Phys­i­cal De­scrip­tion

Like other mem­bers of the genus Mi­cro­gale, M. dryas is shrew-like in ap­pear­ance. Its pelage is soft, short, and dense. It ranges in length from 170 to 180 mm, and weighs an av­er­age of 40 g. It is some­what smaller than closely re­lated species like M. dob­soni and M. gra­cilis. Mi­cro­gale dryas can be dis­tin­guished from these species by its rel­a­tively short, grey tail and its dis­tinc­tive pelage. The ven­tral pat­tern is gen­er­ally red­dish- or grey-brown. The dor­sal pat­tern is unique be­cause the guard hairs are long, with the mid-re­gion of each hair flat and broad. (Gar­butt, 1999; Good­man and Ben­stead, 2004)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Average mass

  40 g

  1.41 oz

• Range length

  170 to 180 mm

  6.69 to 7.09 in

Re­pro­duc­tion

Re­pro­duc­tive and mat­ing be­hav­ior of M. dryas is not well known. In other mem­bers of the genus, males and fe­males may have sta­ble re­la­tion­ships. Mi­cro­gale dob­soni males and fe­males as­so­ci­ate with one an­other throught the year, and may be monog­a­mous. (Nowak, 1999)

Al­though spe­cific in­for­ma­tion about gen­eral re­pro­duc­tive be­hav­ior of M. dryas is un­known, the re­pro­duc­tive be­hav­iors of other mem­bers of the genus Mi­cro­gale are de­scribed below.

Re­pro­duc­tion gen­er­ally be­gins with the onset of the rainy sea­son in north-east­ern Mada­gas­car in Sep­tem­ber. Preg­nancy lasts 2 to 3 months, and lit­ters are gen­er­ally born in No­vem­ber. There are gen­er­ally be­tween 1 and 4 off­spring per lit­ter. Fe­males re­pro­duce no more than twice in one year.

In M. ta­lazaci, neonates weigh an av­er­age of 3.6 g. These young are weaned at about one month of age. Sex­ual ma­tu­rity oc­curs at 21 months of age.

It is likely that M. dryas is like other mem­bers of the genus in these pa­ra­me­ters. (Grz­imek, 2003)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding interval

  Tree shrew tenrecs probably reproduce 1 to 2 times per year.

• Breeding season

  Matingin the genus Microgale usually occurs in September or October

• Range number of offspring

  1 to 4

• Range gestation period

  2 to 4 months

• Average weaning age

  1 months

The spe­cific parental in­vest­ment and care pat­terns for M. dryas are not known. In­for­ma­tion from re­lated species in the same genus in­di­cates that parental in­vest­ment is sim­i­lar to that of true shrews, So­ri­ci­dae. Off­spring are rel­a­tively help­less and re­main in a nest guarded by the mother for about a month. Fe­males of this genus care for the off­spring, pro­vid­ing milk, groom­ing, and pro­tec­tion. The role of males in parental care has not been doc­u­mented. (Grz­imek, 2003; Grz­imek, 2003; Grz­imek, 2003)

• Parental Investment
• no parental involvement
• altricial
• female parental care
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female

Lifes­pan/Longevity

The lifes­pan of M. dryas is not known. Mem­bers of the fam­ily Ten­re­ci­dae gen­er­ally live up to 6 years in the wild. (Grz­imek, 2003)

Be­hav­ior

Lit­tle is known about the be­hav­ior of M. dryas be­cause it is rarely seen and is crit­i­cally en­dan­gered. How­ever, some be­hav­ioral traits have been ob­served of more com­mon mem­bers of the genus Mi­cro­gale, and these may be sim­i­lar to those of M. dryas. These species tend to be ter­res­trial and in­sec­tiv­o­rous. They ap­pear to be ac­tive at ir­reg­u­lar in­ter­vals with for­ag­ing oc­cur­ring dur­ing the day or at night. Some build nests for their young. They are gen­er­ally soli­tary in the wild, and are ag­gres­sive to­ward un­fam­liar mem­bers of their species, but in­stances of pair-bond­ing have been doc­u­mented in cap­tive pop­u­la­tions. (Gar­butt, 1999; Grz­imek, 2003; Nowak, 1999)

• Key Behaviors
• terricolous
• diurnal
• nocturnal
• crepuscular
• motile
• solitary

Home Range

The size of the home range of these an­i­mals is not known. How­ever, other mem­bers of the genus are ag­gres­sive to­ward strangers, so it is likely that these an­i­mals are ter­ri­to­r­ial. (Nowak, 1999)

Com­mu­ni­ca­tion and Per­cep­tion

Lit­tle is known about com­mu­ni­ca­tion and per­cep­tion of M. dryas, how­ever other species of the genus Mi­cro­gale have shown the fol­low­ing traits. They tend to have a well-de­vel­oped sense of smell as well as tac­tile sense, es­pe­cially through their whiskers (vib­ris­sae). Some mem­bers of the genus pro­duce a sound that may be used for com­mu­ni­ca­tion, but sense of smell is likely the most im­por­tant chan­nel for com­mu­ni­ca­tion. Ag­o­nism be­tween un­fa­mil­iar in­di­vid­u­als is a form of tac­tile com­mu­ni­ca­tion. It is not known whether these an­i­mals use vi­sual sig­nals for com­mu­ni­ca­tion. (Grz­imek, 2003; Nowak, 1999; Wil­son and Reeder, 1993)

• Communication Channels
• tactile
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

M. dryas, like most other ten­recs, is pri­mar­ily an in­sec­ti­vore. These an­i­mals con­sume a va­ri­ety of in­ver­te­brates, in­clud­ing in­sects and arach­nids. It is un­known whether M. dryas con­sumes plant ma­te­ri­als or small ver­te­brates like its rel­a­tives in the fam­ily Ten­re­ci­dae. (Gar­butt, 1999; Grz­imek, 2003; Wil­son and Reeder, 1993)

• Primary Diet
• carnivore
  • insectivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

Pre­da­tion

Preda­tors of M. dryas are likely larger sized mam­mals, rep­tiles, and birds. Ev­i­dence of M. dryas was found in pel­lets from a Mada­gas­car red owl. It is pos­si­ble that the noc­tur­nal be­hav­ior of M. dryas is an anti-preda­tor adap­ta­tion. No other adap­ta­tions to avoid pre­da­tion are known in this species. (Good­man and Ben­stead, 2004; Nowak, 1999; Wil­son and Reeder, 1993)

• Known Predators

  • Madagascar red owls (Tyto soumagnei)

Ecosys­tem Roles

The role that M. dryas has in its ecosys­tem is un­known. It is not a com­mon species, and has a very re­stricted range. Al­though it acts as preda­tor for a va­ri­ety of in­sects, it is not known how it im­pacts their pop­u­la­tions. Sim­i­larly, al­though it may serve as prey to a num­ber of other an­i­mals, it is not known whether it is an im­por­tant prey item for these species, or how the avail­abil­ity of M. dryas as a food source af­fects these other an­i­mals.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are no known ben­e­fits that M. dryas has on hu­mans. Be­cause it is so rare, it is likely that it does not af­fect the ecosys­tem or hu­mans greatly. ("In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources", 2003)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse af­fects of M. dryas on hu­mans.

Con­ser­va­tion Sta­tus

The IUCN lists M. dryas as the only crit­i­cally en­dan­gered mem­ber of the Ten­re­ci­dae. It has only been found in the Am­bat­o­vaky Spe­cial Re­serve and is ex­tremely rare. The on­go­ing major threat to this pop­u­la­tion is habi­tat loss due to slash and burn agri­cul­ture and de­struc­tion of the rain­forests. It is listed as crit­i­cally en­dan­gered be­cause it is only found at a sin­gle lo­ca­tion and the num­ber of these an­i­mals is thought to be de­clin­ing. ("In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources", 2003; Crow­ley, 2001; Gar­butt, 1999; Nowak, 1999)

• IUCN Red List

  Vulnerable
  More information

• IUCN Red List

  Vulnerable
  More information

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Nancy Shef­ferly (ed­i­tor), An­i­mal Di­ver­sity Web.

Heather Gille­spie (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor, in­struc­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2003. "In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources" (On-line). Ac­cessed April 15, 2004 at http://​www.​redlist.​org/​search/​details.​php?​species=13356.

Crow­ley, H. 2001. "Mada­gas­car low­land forests (AT0117)" (On-line). World Wildlife Fed­er­a­tion. Ac­cessed April 16, 2004 at http://​www.​worldwildlife.​org/​wildworld/​profiles/​terrestrial/​at/​at0117_​full.​html.

Gar­butt, N. 1999. Mam­mals of Mada­gas­car. New Haven and Lon­don: Yale Uni­ver­sity Press.

Good­man, S., J. Ben­stead. 2004. The Nat­ural His­tory of Mada­gas­car. Chicago and Lon­don: Uni­ver­sity of Chicago Press.

Grz­imek, B. 2003. Ten­recs. Pp. 225-230 in Grz­imek's An­i­mal Life En­cy­clo­pe­dia: Mam­mals, Vol. 13, 2nd Edi­tion. Farm­ing­ton Hills: Gale Group.

Nowak, R. 1999. Walker's Mam­mals of the World, Sixth Edi­tion. Bal­ti­more and Lon­don: The John Hop­kins Uni­ver­sity Press.

Wil­son, D., D. Reeder. 1993. Mam­mal Species of the World: A Tax­o­nomic and Ge­o­graphic Ref­er­ence. Wash­ing­ton and Lon­don: Smith­son­ian In­sti­tu­tion Press.