Etruscan Pygmy Shrew
Encyclopedia
The Etruscan shrew also known as the Etruscan pygmy shrew or the white-toothed pygmy shrew is the smallest known mammal
by mass, weighing only about 1.8 gram
s on average (the Bumblebee Bat
is regarded as the smallest mammal by skull size).
The Etruscan shrew has a body length of about 4 cm excluding the tail. It is characterized by very rapid movements and a fast metabolism
, eating about 1.5–2 times its own body weight per day. It feeds on various small vertebrates and invertebrates, mostly insects, and can hunt individuals of the same size as itself. These shrews prefer warm and damp climates and are widely distributed in the belt between 10° and 30°N latitude stretching from Europe and North Africa up to Malaysia. They are relatively rare and are endangered in some countries.
The Etruscan shrew has a slender (not truncated) body with a length between 3 and 4.5 cm excluding the tail. The tail is longer than half of the body. The body mass varies between 1.3 and 2.4 grams and is usually about 1.8 grams. The head is relatively large, with a long mobile proboscis
, and the hind limbs are relatively small. The Etruscan shrew has a very fast heart beating rate
, up to 1511 beats/min (25 beats/s) and a relatively large heart muscle mass, 1.2% of body weight. The fur color on the back and sides is pale brown, but is light gray on the stomach. The shrew usually has 30 teeth, but the 4th upper intermediate tooth is very small (rudimentary), and is absent in some individuals. Near the mouth growth a dense array of short whiskers, which the shrew actively uses in searching for prey, especially in the night. There is no clear difference in body features between males and females.
periods. Their lifetime is estimated as 2 years, but with a large uncertainty. They protect their territory by making chirping noises and signs of aggressiveness. They tend to groom themselves constantly when not eating and are always moving when awake and not hiding. The hiding periods are short and typically last less than half an hour. A clicking sound is heard when these shrews are moving, which ceases when they rest. The shrews are more active during the night when they make long trips; during the day, they stay near the nest or in a hiding place. They reach their maximum level of activity at dawn.
The movements of the Etruscan shrew are rapid, with a rate of about 780 min−1 (13 s−1). In cold seasons and during shortages of food, the shrews lower the body temperature down to about 12 °C and enter a state of temporary hibernation
to reduce energy consumption. The recovery from this state is accompanied by shivering with the frequency of about 3500 min−1 (58 s−1). This induces heating with the rate up to 0.83 °C/min, which is among the highest values recorded in mammals; the heart rate increased exponentially with time from 100 to 800–1200 beats/min, and the respiratory rate rises linearly from 50 to 600–800 beats/min.
The Etruscan shrew apparently breed all year round with gestation period
of about 28 days and bring 2–6 cubs per litter. Most pregnancies occur between October and December. Cubs are born naked and blind, but quickly develop, becoming independent and sexually mature at 3–4 weeks of age.
. In Southern Europe, it has been found in Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, France, Macedonia, Malta, Montenegro, Greece, Italy, Portugal, Slovenia, Spain, and Turkey, with unconfirmed reports in Andorra, Gibraltar and Monaco; it has been introduced by humans to some European islands, such as Canary Islands.
The shrew also occurs in Northern Africa (Algeria, Egypt, Libya, Morocco, Tunisia) and around Arabian Peninsula
(Bahrain, Israel, Jordan, Lebanon, Oman, Syria, and Yemen including Socotra
). In Asia, it was observed in Afghanistan, Azerbaijan, Borneo, Bhutan, China (Gengma County
only), Burma, Georgia, Guinea, India, Iran, Iraq, Kazakhstan, Laos, Malaysia (Malaysian part of Borneo
island), Nepal, Pakistan, Philippines, Sri Lanka, Tajikistan, Thailand, Turkey, Turkmenistan and Vietnam. There are unconfirmed reports of the Etruscan shrew in West and East Africa (Guinea, Nigeria, Ethiopia) and in Armenia, Brunei, Indonesia, Kuwait and Uzbekistan.
The shrew is relatively rare, especially in Azerbaijan, Georgia (included into the Red Book), Jordan and Kazakhstan (Red Book). Even where not endangered, its density is always lower than of the other shrews living in the area.
thickets along the banks of lakes and rivers, as well as human-cultivated areas (abandoned gardens, orchards, vineyards, olive groves edges of fields). The shrew however avoids intensively cultivated areas, as well as dense forests sand dunes. It is poorly adapted to digging burrows and therefore arranges its nests in various natural shelters, crevices and others uninhabited burrows.
and for this reason avoid ants when given a choice. They kill large prey by a bite to the head and eat them immediately, whereas they take small insects back to their nest. When hunting, the Etruscan shrew mostly rely on their sense of touch rather than vision and may even run into their food at night. The Etruscan shrew might play important role in controlling the insect population.
s.
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
by mass, weighing only about 1.8 gram
Gram
The gram is a metric system unit of mass....
s on average (the Bumblebee Bat
Bumblebee Bat
Kitti's Hog-nosed Bat , also known as the bumblebee bat, is a vulnerable species of bat and the only extant member of the family Craseonycteridae. It occurs in western Thailand and southeast Burma, where it occupies limestone caves along rivers.Kitti's Hog-nosed Bat is the smallest species of bat...
is regarded as the smallest mammal by skull size).
The Etruscan shrew has a body length of about 4 cm excluding the tail. It is characterized by very rapid movements and a fast metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
, eating about 1.5–2 times its own body weight per day. It feeds on various small vertebrates and invertebrates, mostly insects, and can hunt individuals of the same size as itself. These shrews prefer warm and damp climates and are widely distributed in the belt between 10° and 30°N latitude stretching from Europe and North Africa up to Malaysia. They are relatively rare and are endangered in some countries.
Description
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
, and the hind limbs are relatively small. The Etruscan shrew has a very fast heart beating rate
Heart rate
Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....
, up to 1511 beats/min (25 beats/s) and a relatively large heart muscle mass, 1.2% of body weight. The fur color on the back and sides is pale brown, but is light gray on the stomach. The shrew usually has 30 teeth, but the 4th upper intermediate tooth is very small (rudimentary), and is absent in some individuals. Near the mouth growth a dense array of short whiskers, which the shrew actively uses in searching for prey, especially in the night. There is no clear difference in body features between males and females.
Activity
The Etruscan shrew live alone, except during matingMating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
periods. Their lifetime is estimated as 2 years, but with a large uncertainty. They protect their territory by making chirping noises and signs of aggressiveness. They tend to groom themselves constantly when not eating and are always moving when awake and not hiding. The hiding periods are short and typically last less than half an hour. A clicking sound is heard when these shrews are moving, which ceases when they rest. The shrews are more active during the night when they make long trips; during the day, they stay near the nest or in a hiding place. They reach their maximum level of activity at dawn.
The movements of the Etruscan shrew are rapid, with a rate of about 780 min−1 (13 s−1). In cold seasons and during shortages of food, the shrews lower the body temperature down to about 12 °C and enter a state of temporary hibernation
Torpor
Torpor, sometimes called temporary hibernation is a state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. Animals that go through torpor include birds and some mammals such as mice and bats...
to reduce energy consumption. The recovery from this state is accompanied by shivering with the frequency of about 3500 min−1 (58 s−1). This induces heating with the rate up to 0.83 °C/min, which is among the highest values recorded in mammals; the heart rate increased exponentially with time from 100 to 800–1200 beats/min, and the respiratory rate rises linearly from 50 to 600–800 beats/min.
The Etruscan shrew apparently breed all year round with gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of about 28 days and bring 2–6 cubs per litter. Most pregnancies occur between October and December. Cubs are born naked and blind, but quickly develop, becoming independent and sexually mature at 3–4 weeks of age.
Distribution
The Etruscan shrew inhabits a belt extending between 10° and 40°N latitude across EurasiaEurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
. In Southern Europe, it has been found in Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, France, Macedonia, Malta, Montenegro, Greece, Italy, Portugal, Slovenia, Spain, and Turkey, with unconfirmed reports in Andorra, Gibraltar and Monaco; it has been introduced by humans to some European islands, such as Canary Islands.
The shrew also occurs in Northern Africa (Algeria, Egypt, Libya, Morocco, Tunisia) and around Arabian Peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...
(Bahrain, Israel, Jordan, Lebanon, Oman, Syria, and Yemen including Socotra
Socotra
Socotra , also spelt Soqotra, is a small archipelago of four islands in the Indian Ocean. The largest island, also called Socotra, is about 95% of the landmass of the archipelago. It lies some east of the Horn of Africa and south of the Arabian Peninsula. The island is very isolated and through...
). In Asia, it was observed in Afghanistan, Azerbaijan, Borneo, Bhutan, China (Gengma County
Gengma Dai and Va Autonomous County
Gengma Dai and Va Autonomous County is located in Lincang Prefecture, Yunnan, China.-External links:*...
only), Burma, Georgia, Guinea, India, Iran, Iraq, Kazakhstan, Laos, Malaysia (Malaysian part of Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
island), Nepal, Pakistan, Philippines, Sri Lanka, Tajikistan, Thailand, Turkey, Turkmenistan and Vietnam. There are unconfirmed reports of the Etruscan shrew in West and East Africa (Guinea, Nigeria, Ethiopia) and in Armenia, Brunei, Indonesia, Kuwait and Uzbekistan.
The shrew is relatively rare, especially in Azerbaijan, Georgia (included into the Red Book), Jordan and Kazakhstan (Red Book). Even where not endangered, its density is always lower than of the other shrews living in the area.
Habitat
The Etruscan shrew favors warm and damp habitats covered with shrubs, which it uses to hide from predators. It is usually confined to the foothills and lower belts of mountain ranges, though has been found up to 3,000 m above sea level. It colonizes riparianRiparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by...
thickets along the banks of lakes and rivers, as well as human-cultivated areas (abandoned gardens, orchards, vineyards, olive groves edges of fields). The shrew however avoids intensively cultivated areas, as well as dense forests sand dunes. It is poorly adapted to digging burrows and therefore arranges its nests in various natural shelters, crevices and others uninhabited burrows.
Hunting and feeding
Because of their high ratio of surface area to body volume, the Etruscan shrew have an extremely fast metabolism and have to eat 1.5–2 times their body weight in food per day. They feed up to 25 times per day, mostly on various invertebrates (insects, their larvae, earthworms, etc.) as well as small vertebrates (young frogs, lizards and rodents), and can hunt prey of nearly the same body size as themselves. They prefer species with a soft and thin exoskeletonExoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
and for this reason avoid ants when given a choice. They kill large prey by a bite to the head and eat them immediately, whereas they take small insects back to their nest. When hunting, the Etruscan shrew mostly rely on their sense of touch rather than vision and may even run into their food at night. The Etruscan shrew might play important role in controlling the insect population.
Predators and threats
The largest threat to the Etruscan shrew originates from human activities, particularly destruction of their nesting grounds and habitat as a result of farming. The Etruscan shrew is also sensitive to climate changes such as cold winters and dry periods. Major predators are birds of prey, especially owlOwl
Owls are a group of birds that belong to the order Strigiformes, constituting 200 bird of prey species. Most are solitary and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish...
s.