Sources : Bat

Ovid [1st century CE] (The Metamorphosis, Book 4, 389): While they seek the shadows, a thin membrane stretches over their slender limbs, and delicate wings enfold their arms. The darkness prevents them knowing how they have lost their former shape. They do not rise on soft plumage, but lift themselves on semi-transparent wings, and trying to speak emit the tiniest squeak, as befits their bodies, and tell their grief in faint shrieks. They frequent rafters, rather than woods, and, hating the light, they fly at night, and derive their name, ‘vespertiliones’, from ‘vesper’, the evening. - [Kline translation]

Pliny the Elder [1st century CE] (Natural History, Book 10, 81): The only viviparous creature that flies is the bat, which actually has membranes like wings; it is also the only flier that nourishes its young with milk, bringing them to its teats. It bears twins, and flits about with its children in its arms, carrying them with it. The bat is mid to have a single hipbone. Gnats are its favorite fodder. - [Rackham translation]

Saint Ambrose [4th century CE] (Hexameron, Book 5, chapter 24.87): The bat is an ignoble creature, whose name is taken from the word for evening. They are equipped with wings, but at the same time they are quadrupeds. They are provided with teeth, in this respect differing generally from other birds. As a quadruped, too, the female brings forth her young alive and not in the oval stage. Bats fly in the air like birds but prefer to be shrouded in the dusk of evening. In flight they do not use the support of wings but rely on their webbed feet which serve as wings, both as a balance and as a means of propulsion. These common creatures have this faculty, too, of adhering one to another, assuming any position like a pendant bunch of grapes, so that, if the lowest in place gives way they all fall apart. - [Savage translation, 1961]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 7:36): The bat (vespertilio) takes its name from the time of day, because it avoids the light and flies around in the dusk of evening (vespertinus), making darting movements and supported by delicate arm-like limbs. It is an animal similar to a mouse, producing not so much a call as a squeak. In appearance it is a quadruped at the same time as being equipped to fly; this is not usually found among other birds. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.116): Vespertilio is called vespere using ala, as he says [i.e. Liber rerum], for it flies only in the evening and at night. It hides in the winter. It rarely or never proceeds to pasture. It hangs on walls or lies in caves like the dead. And if you bring it to the heat of the sun and the clear air, it gradually stirs itself up and returns to its original vigor and returns to slumber. There are no feathers on the body, no feathers on the wings. It is similar in form to a mouse, seeing that these birds give birth and suckle from their udders after the manner of cattle, except that it has a tail and wings shaped like a bird's, yet with these there are no feathers, but only membranes of stretched skin. The flying parent embraces and carries its babies. Its blood, when struck with a thistle, is the chief remedy against a snake. As the Liber Kyrannidarum says, its blood, when used on fallen hair, allows you to regain your hair. As Pliny says, it likes mosquitoes as its food. It has features like feet on its tail, and some on the wings; but they never use these in the service of living. For when it has to pause, it leans on his chest, face, or wings. This vile animal has it, that they adhere to each other and hang from some place as if in the form of a bundle, and if the last one looses itself, they all fall. It has teeth, which we do not usually find in other birds. In India there are bats larger than pigeons, having teeth like those of men, with which they strike men in the face, cutting off their noses and ears and other parts. - [Badke translation/paraphrase]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book12.38): The reremouse is called Vespertilio, & hath that name of the eventide. For it hating light, flieth in the eventide with breaking and blenching, and swifte mooving, with full small skinnes of her wings. And is a beast like to a mouse in sownding with voice, in piping, and crieng. And he is lyke to a Birde, and also to a foure footed beast: & that is but seld found among Birdes. Huc usque Isidorus. Also super Esaiam. 2. the Glose sayth that these Reremise flye light, for they be blinde as Moles, and lyke powder, and suck Oyle out of Lampes: And they hide themselves in chins and cliffes of walles, and be most colde of kinde. Therfore the bloud of a Reremouse annointed uppon the eie liddes, suffereth not the haire to growe againe, as Constantine saith. And that perchance is because it stoppeth the poores with his coldnesse. And when he poores be stopped, haire groweth not againe. - [Batman]