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Descrizione
- Insettivoro della famiglia dei soricidi e del
genere Suncus. Lunghezza dalla testa
all'attaccatura della coda 64 - 88 mm; coda 42 - 64 mm;
peso 1.8 - 3 gr. il mustiolo è uno dei più piccoli
mammiferi del mondo. l'insettivoro più piccolo che si
conosca (uno dei più piccoli mammiferi del mondo e il
più piccolo in Europa) con una lunghezza del corpo che
va da 3,6 a 5,3 cm. Ha un aspetto esile (pesa da 1 a 3
g) con il muso appuntito, le orecchie sporgenti, gli
occhi piccoli e le zampe piccole e gracili. La coda è
lunga circa la metà del corpo (da 2,1 a 3 cm) ed è
ricoperta da 2 tipi di pelo: alcuni sottili, corti e
compatti e altri lunghi e sparsi. La pelliccia è
generalmente grigia, con la regione dorsale che tende al
marrone e quella ventrale ad un grigio più chiaro.
Sembra che esista un lieve dimorfismo sessuale, per il
quale i maschi sono leggermente più piccoli delle
femmine. 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 et al., 1995; McNab, 1988; Nowak, 1990) |
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Abitudini
- 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). 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).
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) |
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Alimentazione
- 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). |
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Riproduzione
- 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).
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). 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). |
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Habitat
e Area di Distribuzione
- 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).
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 et al., 1995; Dobson,
1998; Nowak, 1990) |
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