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Blanford's jerboa
Like all jerboas, Jaculus blanfordi are saltatorial animals that
have specialized adapatations for their desert environments. All
jerboas have elongated hind-limbs that are about four times as long
as their forelimbs. The short forelimbs are positioned close to the
head and used for gathering food and burrowing. Locomotion is
performed using the hind-feet and the posterior end of their long
tails.
A unique adaptation of members of this genus is the fusion of the
metatarsal bones into one "cannon bone" as well as the loss of the
first and fifth toes on each hind foot. Undersides of the three
remaining long and laterally compressed toes are covered with thick,
stiff hairs. The combination of these features improves traction and
provides powerful leverage, so it's not surprising that members of
this genus can jump to heights of nearly 2.25 m when escaping
predators.
The pelage is thick, comprised of thin and soft hairs that are
dorsally cream-colored but blending with white ventral hairs along
the sides of the body. The eye-lashes and long sensory hairs are
gray or black, and the whiskers are white. The thick
and compressed toe hairs are white near the skin and dark brown on
the outer edges. The tail tuft is divided black anteriorly and white
posteriorly. They have large, round eyes that are set close to the
ears, ovally elongated ears that are relatively small compared to
other dipodids, and a fold of skin which can be pulled over the nose
while burrowing.
Reproduction
Very little is known about the reproductive cycle of this species.
Based on data from other members of the genus and from a few
available collected specimens of Jaculus blanfordi, the gestation
period is believed to be approximately forty days long. One to three
litters are born each year and litters generally
consist of three to four altricial young.
Behavior
Jaculus blanfordi are non-colonial, nocturnal rodents that spend
their days sleeping and nights foraging. They build intricate
burrows by beating and shaping the sand with their blunt heads and
muscular noses, forming tunnels between 1.5-2.5 meters long. The
burrows are characterized by one entrance and several exits. If a
mound of soil is visible from above-ground, it is an indication of
an emergency exit that the individual sometimes forms by lightly
packing a hole and leaving it closed until an emergency arises.
There are no food storages or excrements kept inside the burrows,
but camel fur or other soft materials may be used to line the dens
during the winter months. During
the summer months, the openings are sealed with approximately 50cm
of soil, an act that bedouins believe is to prevent snakes or warm
air from penetrating into the burrow.
At night Jaculus blanfordi forage independently, sometimes over
distances of several miles. Individual burrow systems are in close
proximity to each other and, on numerous instances, individuals have
been found sleeping in the same burrow during the day. Further
studies are needed to determine the social systems of this species.
Other species of this genus have been reported to hibernate in
extreme temperatures. Although this behavior has not been studied in
this species, Jaculus blanfordi in Iran have been observed to be
actively foraging above ground late in December with temperatures
below freezing. Daily cycles of complete torpidity in colder winter
months have also been observed in captive individuals.
Food Habits
The diet consists mainly of leaves and sprouting vegetation in wet
seasons and of succulent roots, seeds and grains when rainfall is
low or in the summer. In captivity they should be offered a complete diet
of rodent lab blocks, and rat or mouse
mix, with bits of fruit or veggies regularly. Cheerios or wheat
bread are great treats, in small quantities. Do NOT feed chocolate,
fried foods, salted foods, candy or junk food! They may enjoy
crickets and mealworms if they are captive bred, never feed wild
insects as they may carry parasites. Vitamins, like Nutri-Cal are a good addition to their diet, and added calcium
during nursing and growth due to demands on their systems at those
times, but take care not to overdo it. Water bottles should be used
to proved constant, clean water. Ceramic or stoneware food dishes
work well for keeping seeds or fresh foods off the floor, and a wire
mesh hopper that allows them to eat the lab blocks through without
extra waste.
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