... Vampire Bat (Desmodus rotundus) ...
by Infocostarica Staff
Desmodus is by far the most abundant bat throughout its
geographic range, which stretches from northern Mexico through Argentina. The common
vampire bat feeds exclusively from blood of vertebrates.
The vampire is capable of olfactory orientation but has
large eyes and better visual acuity than other chiropterans. It uses low-intensity calls
for echolocation, best suited for the detection of larger objects. Which sense, or which
combination of sensory modalities, usually is used to find prey is not yet known.
The superior incisors of the vampire are razor sharp and are
used to remove a small piece of flesh from the prey. A number of studies have demonstrated
the presence of anticoagulant or fibronolytic activities of the saliva.
Presumably Desmodus experienced a population
explosion when domestic animal where brought to the New World. These afforded the vampires
a more accessible an more plentiful supply of blood than did the native wildlife. Today
serological tests of blood meals of Desmodus in Mexico, Trinidad, and Costa Rica
indicate a nearly complete switch of domestical animals, particularly cattle, horses and
poultry.
On its foraging flights, the vampire avoids moonlit periods.
Presumably it hunts alone, or at most, in small groups. Upon locating a prey animal, it
lands either directly on its body or on the ground, especially if the prey is bedded down.
It bites cattle at various places, on the body and quite often on the neck.
Vampires roost communally during the day in tree hollows,
abandoned wells, caves and such. Their roosts are easily distinguishable from the used
exclusively by other bat species because of the potent ammonia odor and by the dark
orange, viscous "goo" their excreta, on the floor and the walls.
Both sexes roost together, and roost turnover for
individuals can be very high when a number of potential roosts exists close by ; but
vampires have also been reported to use the same roost for long periods. Self-grooming and
social grooming in the roost are very common.
Although pregnant vampires can be netted in any month of the
year and it is said that high pregnancy activity rates for the wet seasons on northern
Costa Rica, and this may be related to pray availability. In captivity mothers feed young
vampires blood from their mouths at 3 months of age, and juveniles visit prey with their
mothers at 5 or 6 months of age.
Though their unique feeding habits, vampires can transmit a
number of diseases, the most serious, of course, being paralityc rabies. Desmodus is known to survive the virus itself, in infection rates appear to be low in naturally
occurring populations. |
