Information about the Bat
Bats are placental mammals and they are the second largest order as rodents do come first and it is also making up approx. 20% of mammal species. Not all mega bats are larger than microbats as several characteristics do distinguish the two groups as we can find that microbats do use echolocation for navigation and finding prey, on the other hand mega bats apart from those in the genus Rousettus do not but instead of that they do rely on their eyesight and according to that, mega bats do have a well-developed visual cortex and good visual acuity.
Mega bats do have a claw on the second finger of the forelimb and also the external ears of microbats do not close to form a ring as the edges are separated from each other at the base of the ear, mega bats do eat fruit, nectar, or pollen, while most of microbats do eat insects and others do feed on fruit, nectar, pollen, fish, frogs, small mammals, or blood.
The head and the teeth shape of bats can vary by species, mega bats do have longer snouts, larger eye sockets and smaller ears and this does give them a more dog-like appearance which is the source of their nickname of “flying foxes”, on the other hand microbats do have longer snouts which are associated with nectar-feeding, while vampire bats have reduced snouts to accommodate large incisors and canines.
The small insect-eating bats can do have as many as 38 teeth, while vampire bats do have only 20, also bats that do feed on hard-shelled insects have fewer but larger teeth with longer canines and more robust lower jaws than species that do prey on softer bodied insects, and in nectar-feeding bats the canines are long while the cheek-teeth are reduced, in fruit-eating bats the cusps of the cheek teeth are adapted for crushing and these feeding behaviors are true for both mega bats and microbats but the upper incisors of vampire bats do lack enamel which does keeps them razor-sharp and the bite force of small bats is been generated through mechanical advantage to allow them to bite through the hardened armour of insects or the skin of fruit.
Bats are the only mammals capable of sustained flight as they are opposed to gliding as in the flying squirrel and the fastest bat is the Mexican free-tailed bat which can achieve a ground speed of 160 km/h.
The finger bones of the bats are much more flexible than those of other mammals as owing to their flattened cross-section and to low levels of calcium near their tips and the elongation of bat digits, a key feature which is required for wing development, is because of the upregulation of bone morphogenetic proteins.
Bats do have five elongated digits which do radiate around the wrist and the thumb points do forward and support the leading edge of the wing and the other digits do support the tension held in the wing membrane but the second and third digits do go along the wing tip to allow the wing to be pulled forward against aerodynamic drag and this will be without having to be thick as in pterosaur wings, the fourth and fifth digits do go from the wrist to the trailing edge and do repel the bending force that was caused by air pushing up against the stiff membrane.
The patagium is the wing membrane which is stretched between the arm and finger bones down the side of the body to the hind limbs and tail and this skin membrane does consist of connective tissue, elastic fibres, nerves, muscles, and blood vessels.
To achieve flight, a bat does exert force inwards at the points where the membrane does meet the skeleton so that an opposing force does balance it on the wing edges perpendicular to the wing surface and this adaptation does not permit bats to do reduce their wingspans and this does mean bats cannot travel over long distances as birds can.
When not flying, bats do hang upside down from their feet, a posture known as roosting, the femurs are been attached at the hips in a way that does allow them to bend outward and upward in flight and the ankle joint can flex to do allow the trailing edge of the wings to do bend downwards, and this does not permit many movements other than hanging or clambering up trees, also tendons do allow bats to lock their feet closed when they do hang from a roost.
When they are on the ground, most bats can do only crawl awkwardly and few species only such as the New Zealand lesser short-tailed bat and the common vampire bat are agile on the ground and both species do make lateral gaits when they do move slowly but the vampire bats do move with a bounding gait at greater speeds and the folded up wings that is being used to propel them forward, also the vampire bat likely did evolve these gaits to follow their hosts while short-tailed bats did develop in the absence of terrestrial mammal competitors.