Microgale dobsoniDobson's shrew tenrec

Last updated:

Geographic Range

All members of the genus Microgale are confined to Madagascar. Microgale dobsoni occurs in eastern and east-central Madagascar on the central high plateau.

Habitat

Microgale dobsoni occurs generally in second growth deciduous forests subjected to seasonal rainfall and cool temperatures during the winter.

Physical Description

The mass of this small insectivore varies by season. Without fat reserves, an individual weighs between 34-45g. With fat reserves stored in the tail and body, a single individual in captivity reached 84g. All members of the genus Microgale possess a cloaca (a single opening for the digestive, urinary and reproductive tracts), a trait that is considered primitive for mammals. Microgale dobsoni is shrew-like in general appearance, has a grey-brown back, a grey belly, and a tail almost as long as its head and body. Measurements: Head-Body: 92-114mm; Tail: 102-108mm; Hind Foot: 19-24mm.

  • Average mass
    37.8 g
    1.33 oz
    AnAge
  • Average basal metabolic rate
    0.315 W
    AnAge

Reproduction

Very little is known about the reproduction of M. dobsoni in the wild. In captivity, copulation occurs from December to August and young are born from February to May. When M. dobsoni was trapped in the wild during the month of April, no lactating females were captured and none of the animals were fully adult. This suggests that the breeding season is considerably shorter in the wild than in captivity.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    2.67
    AnAge
  • Average gestation period
    61 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    669 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    669 days
    AnAge

Lifespan/Longevity

Behavior

Microgale dobsoni is solitary and live in populations with individuals well spaced in the wild. They are primarily nocturnal and communicate with sound and scent. Vocalizations range from a soft twittering squeak to a loud scream. Both males and females give a repeated soft squeak during initial contact with unknown conspecifics. It is thought that this vocalization serves to reduce aggression and facilitate contact, especially between males and females. If interactions between conspecifics become aggressive, one or both interactors will give a loud repeated squeal. Finally, if threatened by a hostile conspecific or a predator, the animal will emit a single piercing scream. Shrew tenrecs also communicate by scent. Both male and female shrew tenrecs will mark areas with secretions from their cloacal openings as they move through a new area or during male-female encounters. Shrew tenrecs groom themselves by spreading saliva over their face and paws. It is possible that this saliva may function in olfactory communication during conspecific contact. Microgale dobsoni does not usually enter torpor, but if the animal has sufficient fat reserves, it will become inactive, eat less and allow its body temperature to fluctuate to some degree with the ambient temperature.

Communication and Perception

Food Habits

Microgale dobsoni is insectivorous. In captivity, it readily eats insects, earthworms and raw ground meat. In the wild, it probably subsists on a diet of insects supplemented with ant eggs.

Economic Importance for Humans: Positive

None known.

Economic Importance for Humans: Negative

None known.

Conservation Status

This species of Microgale is not specifically threatened, but the island of Madagascar is rapidly losing much of its endemic fauna due to rapid deforestation of the tropical rainforest. Microgale dobsoni's ability to live in second growth forest may save it from extinction.

Contributors

Sharon Jansa (author), University of Minnesota.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

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.

chemical

uses smells or other chemicals to communicate

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.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

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.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

References

Eisenberg, J.F. and E. Gould (1970) The Tenrecs: A study in mammalian behavior and evolution. Smithsonian Contributions to Zoology, No. 27. Smithsonian Institution Press (Washington).

MacPhee, R.D.E (1987) The Shrew Tenrecs of Madagascar: Systematic revision and Holocene distribution of Microgale (Tenrecidae, Insectivora). American Museum Novitates 2889:1-45.