A very singular animal is the bat, and seems to belong to several
classes and orders. The specimen we present here (_Atalapha cinerea_)
is very rare in this part of the country, and was taken in Lincoln
Park, Chicago. It flies through the air like a bird and, possessing
mammæ like the quadrupeds, suckles its young. The double jaw is
provided with three kinds of teeth. With the canines and incisors
it tears its prey like carnivorous animals, and with the molars or
grinders it cracks nuts like rodents, which it resembles in the narrow,
oval form of its head. An imperfect quadruped when on the ground, it
drags itself along, embarrassed by the mantle of its wings, which fold
up around its legs like an umbrella when closed. When it undertakes to
fly it does so in an awkward manner. It first crawls painfully along,
and with great difficulty extends its long fingers, spreading out the
membrane which covers and binds them together. The ungainly creature
then quickly flaps its broad wings, tough as leather, but thin and
transparent; a bird without plumage, it now flies abroad in pursuit of
insects--nocturnal like itself--or in search of ripe fruit, to which
some species are particularly destructive.
None of the bats like to raise themselves into the air from a perfectly
level surface, and, therefore, use all their endeavors to climb to
some elevated spot, from whence they may launch themselves into the
air. They climb with great ease and rapidity, being able to hitch
their sharp and curved claws into the least roughness that may present
itself, and can thus ascend a perpendicular wall with perfect ease and
security. In so doing they crawl backward, raising their bodies against
the tree or wall which they desire to scale, and drawing themselves
up by the alternate use of the hinder feet. When they have attained
a moderate height, they are able to fling themselves easily into the
air and to take immediate flight. They have the power of rising at
once from the ground, but always prefer to let themselves fall from
some elevated spot. One reason why bats take their repose suspended
by their hind feet is said to be that they are then in the most
favorable position for taking to the air. There may be, and probably
are, other reasons for the curious reversed attitude. Even among the
birds examples are found of a similar mode of repose. Members of the
genus _Colius_, an African group of birds, sleep suspended like the
bats, clinging with their feet and hanging with their heads downward.
But these birds cannot assume this attitude for the purpose of taking
flight, as their wings are used as readily as those of most other
feathered creatures, and, therefore, there must be other reasons to
account for the strange attitude.
The more closely we approach the torrid zone, it is said, the greater
is the number of bats and the richer their variety. The South is the
native country of the majority of wing-handed animals. Even in Italy,
Greece, and Spain, the number of bats is surprising. There, according
to Brehm, who studied them industriously, as evening draws nigh they
come out of their nooks and corners not by hundreds but by thousands.
Out of every house, every old stone wall, every rocky hollow they
flutter, as if a great army were preparing for a parade, and the entire
horizon is literally filled with them. The swarms of bats one sees in a
hot country are astonishing. They darken the sky. Everywhere there is a
living and moving mass flying through the trees or gardens and groves.
Through the streets of the town, through houses and rooms flits the
moving train. Hundreds are constantly appearing and disappearing and
one is always surrounded by a hovering swarm.
A feature of the wings of bats, is a highly elastic skin. The outer
layer is constantly kept pliable by anointing with an oily liquid,
secreted by glands in the animal's face. The structure of the hair
is also remarkable, as each thread presents under the microscope a
screw-like appearance.