Suncus etruscuswhite-toothed pygmy shrew

Geographic Range

Etruscan shrews, Suncus etruscus, have a wide distribution, but they are mainly confined to the Mediterranean lowlands from Portugal to the Middle East. There are reports of S. etruscus in Africa. Many former subspecies that have since been elevated to species occur in Southeast Asia and Madagascar. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995; Dobson, 1998; Nowak, 1990)

Habitat

The habitat of Etruscan shrews includes forest, shrub and grassland environments. Suncus hosei, a former subspecies of S. etruscus, has been found in the dipterocarp forests of Asia. Some older accounts report S. etruscus at elevations as high as 4250 meters and as low as 100 meters in Malaysia. However, due to the fact that some subspecies have been elevated to full species, this may not reflect the true elevational range of Suncus etruscus. (Davison, 1979)

  • Range elevation
    630 to 1000 m
    2066.93 to 3280.84 ft

Physical Description

Suncus etruscus may be one of the smallest mammals living today, with most adults weighing between 1.8 and 3 grams and ranging from 35 to 50 mm in length. They tend to be grayish-brown with short soft hair, and they are often recognized by their small hind limbs. There is no apparent sexual dimorphism. The basal metabolic rate of these tiny creatures averages 3.22 cubic centimeters of oxygen per hour. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995; McNab, 1988; Nowak, 1990)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    1.8 to 3 g
    0.06 to 0.11 oz
  • Average mass
    2g g
    oz
  • Range length
    35 to 50 mm
    1.38 to 1.97 in
  • Average basal metabolic rate
    3.22 cm3.O2/g/hr
  • Average basal metabolic rate
    0.063 W
    AnAge

Reproduction

The mating system of Suncus etruscus is not very well understood. In one study it was found that young pairs of S. etruscus did live peacefully during the mating season. It must be noted that the closely related species Suncus varilla appears to be monogamous, and pairs live together throughout the year. The small size and difficulty of capturing S. estruscus makes it difficult to study. It is not known if its behavioral characteristics are similar to those of S. varilla. (Nowak, 1990)

The time in which Suncus etruscus breeds and the information about its young have not been widely studied. However, other species in the genus Suncus have been known to breed at all times of the year, most notably Suncus murinus, which has been widely studied. Most pregnancies occur from October through December. One study of S. etruscus pairs found that the gestation of this species was about 27.5 days and that litter sizes were anywhere from 2 to 6. Weaning in the genus Suncus as a whole is from 17 to 20 days. Suncus varilla apparently reaches sexual maturity about 24 months after birth. Suncus murinus females, however, reach sexual maturity at around 36 days. (Nowak, 1990)

  • Breeding interval
    Not known for this species
  • Breeding season
    Not known for this species
  • Range number of offspring
    2 to 6
  • Average number of offspring
    4
    AnAge
  • Average gestation period
    27.5 days
  • Average gestation period
    27 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    365 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    365 days
    AnAge

All eutherian mammals nurture their young before birth via the placenta, and all mammals provide their newborns with milk. There is little else known about the parental investment of Etruscan shrews. Parental investment by other members of the genus Suncus is quite variable. In the case of Suncus murinus, both parents collect nesting material. Suncus murinus young have been seen caravanning behind their mother when they are learning to find their own food. Suncus varilla young stay with their mother for up to nine months after being weaned, whereas S. murinus young are separated from their parents within a few months. (Nowak, 1990)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

There is little known about the life span of Suncus etruscus, but the lifespans of other species in the genus range from 1.5 to 3 years. Etruscan shrews are hard to keep alive in captivity due to their size and their large energy requirements. (Nowak, 1990; Nowak, 1990)

Behavior

Shrews in general are very active and always foraging for food. This is especially true in the case of Suncus etruscus; being such a small animal, it has high energy demands. These shrews constantly use their long noses to locate food. They appear not to rely on sight to find food, nor do they use their forelimbs to aid in consuming their food. They also tend to groom themselves constantly when not eating and they are always moving. When they are still, they tend to hide under dead leaves, but this has never been seen for more than a half an hour. This behavior has been observed in the wild and in captivity. In the wild they tend to move based on the availability of cover and leaves to hide under. Suncus etruscus is most likely solitary and territorial, except during the breeding season, as is the closely related Suncus murinus. (Davison, 1979; Nowak, 1990)

Communication and Perception

Most shrews in the genus Suncus are solitary and territorial. In order to defend their territories, they all make some sort of chirping noises and show aggressive behavior toward any intruders. When Suncus etruscus is in torpor and then suddenly awakened it makes harsh shrieking calls and this noise is usually only made when it is unable to flee the area.

In a study using captive individuals, it was found that these shrews would make clicking sounds that would become more rapid the faster they were moving. When the animals were motionless the clicking sounds were not heard. It was believed that these sounds could be a form of echolocation; however, this behavior has only been observed in one study.

Shrews seem to rely most heavily on their senses of smell and touch to find food, as they have poor vision. (Davison, 1979; Hutterer, et al., 1979; Nowak, 1990)

Food Habits

Suncus etruscus is an insectivorous species, as are most other shrews. They eat ants and other small insects; in captive studies they have eaten mealworms and crickets. They don’t use their forefeet to aid in consuming food. So, the smaller the food, the easier it can be handled. When captive individuals are given large food pieces, they cannot eat them readily; small pieces need to be detached before they can be eaten. Etruscan shrews rely little on sight in locating food. Sometimes they may even run into their food. They are always looking for food in order to meet their high energy demands. (Davison, 1979; Jurgens, 2002)

  • Animal Foods
  • insects

Predation

Etruscan shrews are extremely small and therefore little is known about their predation. Owls are known predators. Owl pellets often contain the remains of Etruscan shrews. (Hutterer and Kock, 2002)

Ecosystem Roles

Shrews are food for predators such as owls, and probably play a large role in controlling insect populations. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995)

Economic Importance for Humans: Positive

The importance of Suncus etruscus to humans in not known, aside from their importance as members of healthy ecosystems. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995)

Economic Importance for Humans: Negative

There are no known negative affects of Suncus etruscus on humans. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995)

Conservation Status

The conservation status on Suncus etruscus is of least concern. However, some of the former subspecies are threatened. Suncus fellowgordoni is endangered; Suncus hosei is vulnerable. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995)

Other Comments

There are several former subspecies of S. etruscus that have been elevated to full species. These include Suncus madagascariensis, S. fellowsgordoni, S. hosei, and S. malayanus. There is little to no information on these species and some accounts still treat these as subspecies of S. etruscus. All of these species (or subspecies depending on the author) are extremely similar in size and appearance to S. etruscus. ("Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan", 1995; Nowak, 1990)

Contributors

Allison Poor (editor), University of Michigan-Ann Arbor.

Anna Ferry (author), University of Alaska Fairbanks, Link Olson (editor, instructor), University of Alaska Fairbanks.

Glossary

Ethiopian

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

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

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.

carnivore

an animal that mainly eats meat

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.

fertilization

union of egg and spermatozoan

forest

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

insectivore

An animal that eats mainly insects or spiders.

iteroparous

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).

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.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

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

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

1995. "Eurasian Insectivores and Tree Shrews: Status Survey and Conservation and Action Plan" (On-line). Accessed November 05, 2004 at http://members.vienna.at/shrew/itsesAP95-cover.html.

Cagnin, M., S. Moreno, G. Aloise, G. Garofalo, R. Villafuerte, P. Gaona, M. Cristaldi. 1998. Comparative study of Spanish and Itialian terrestrial small mammals coenoses from different biotopes in Mediterranean peninsular tip regions. Journal of Biogeography, 25: 1105-1113.

Davison, G. 1979. Some notes on Savi's Pigmy Shrew. The Malayan Nature Journal, 32/3 and 4: 227-231.

Dobson, M. 1998. Mammal distributions in the western Mediterrranean: the role of human intervention. Mammal Review, 28/2: 77-88.

Hutterer, R., D. Kock. 2002. Recent and acient records of shrews from Syria, with notes on Crocidura katinka Bate, 1937 (Mammalia: Soricidae). Bonner Zoologische Beitrage, 50/3: 249-259.

Hutterer, R., P. Vogel, H. Frey, M. Genoud. 1979. Vocalization of the Shrews Suncus etruscus and Crocidura russula during Normothmia and Torpor. Acta Theriologica, 24/21: 271-276.

Jurgens, K. 2002. Etruscan Shrew Muscle: the conseguences of being small. The Journal of Experimental Biology, 205: 2161-2166.

McNab, B. 1988. Complications Inherent in Scaling and Basal Rate of Metabolism in Mammals. The Quarterly Review of Biology, 63/1: 25-54.

Nowak, R. 1990. Walker's Mammals of the world. Baltimore and London: John Hopkins University Press.