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)
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)
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)
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)
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.
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)
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)
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)
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)
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)
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)
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.
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)
There are no known adverse affects of M. dryas on humans.
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)
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.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
uses sound to communicate
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.
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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
active at dawn and dusk
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.
parental care is carried out by females
union of egg and spermatozoan
An animal that eats mainly insects or spiders.
animals that live only on an island or set of islands.
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).
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
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.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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.