Aristotle [ca. 350 BCE] (De animalibus, Book 4, 9.5-6; 8, 2.2): [Book 4, 9.5] The tongue of the frog is peculiar, for the fore-part of it is fixed, like that of a fish; but the part near the pharynx is free and folded up. With this it utters its peculiar sound. The male frogs make a croaking in the water when they invite the females to coition. [Book 4, 9.6] The frog croaks by making its lower jaw of equal length, and stretching the upper one above the water. Their eyes appear like lights, their cheeks being swelled out with the vehemence of their croaking; for their copulation is generally performed in the night. [Book 8, 2.2] ...they cannot live when separated from the water ... some of the smaller creatures, as the ... frog tribe; for all these are suffocated if their respiration is suspended for any length of time. - [Cresswell translation, 1887]

Ovid [1st century CE] (The Metamorphoses, Book 6, 313-381; 15, 361-390): [Book 6, 313-381] Not content with that, they also stirred the pool with their hands and feet, and churned up the soft mud from the depths, by leaping about, maliciously. Anger forgot thirst, for now the daughter of Coeus could not bear to beg from the unworthy, nor speak in words inferior to those of a goddess, and stretching her palms to the heavens, she said ‘Live in that swamp for ever!’ It happened as the goddess wished: It is their delight to be under the water, now to submerge their bodies completely in the deep pool, now to show their heads, now to swim on the surface. Often they squat on the edges of the marsh, often retreat to the cool lake, but now as before they employ their ugly voices in quarreling, and shamefully, even though they are under the water, from under the water they try out their abuse. Now their voices are also hoarse, their inflated throats are swollen, and their croaking distends their wide mouths. Their shoulders and heads meet, and their necks appear to have vanished. Their backs are green; their bellies, the largest part of their body, are white, and, as newly made frogs, they leap in their muddy pool. [Book 15, 361-390] Mud contains the generative seeds of green frogs, and generates them without legs, soon giving them legs for swimming, and, at the same time, with hind legs longer than their forelegs, so that they are fit to take long leaps. - [Kline translation]

Pliny the Elder [1st century CE] (Natural History, Book 8, 48; 8, 83; 11, 65; 11, 112; 32, 18; 32, 24): [Book 8, 48] Also the bramble-frog [ranae quoque rubetae], which is amphibious in its habit, is replete with a great number of drugs, which it is said to evacuate daily and to replace by the food that it eats, always keeping back only the poisons for itself. [Book 8, 83] At Cyrene the frogs were silent, and though croaking frogs have been imported from the mainland the silent breed goes on. Frogs are also silent in the island of Seriphus, but the same frogs croak when removed to some other place, which is also said to happen in the Siccanean Lake in Thessaly. [Book 11, 65] In frogs the tip of the tongue is attached but the inner part is loose from the throat; it is with this that the males croak, at the time when they are called croakers; this happens at a fixed season, when they are calling the females to mate. In this process they just drop the lower lip and take into the throat a moderate amount of water and let the tongue vibrate in it so as to make it undulate, and a croaking sound is forced out; during this the curves of the cheeks are distended and become transparent, and the eyes stand out blazing with the exertion. [Book 11, 112] Frogs have a special kind of voice, as has been said, unless in their case also we are to allow some uncertainty, because 'voice' means a sound formed in the mouth, not in the chest. Still in the case of frogs the nature of the localities also makes a great deal of difference: the frogs in Macedonia are reported to be dumb... [Book 32, 18] ...if the flesh of river frogs is eaten, or the broth drunk after boiling them down, it counteracts the poison of the sea-hare... Democritus indeed tells us that if the tongue, with no other flesh adhering, is extracted from a living frog, and after the frog has been set free into water, placed over the beating heart of a sleeping woman, she will give true answers to all questions. ... It is certain that frogs' flesh placed in weels or on a hook makes excellent bait for the purple-fish. ... Some frogs there are that live only in brambles, and so they are called bramble-toads [rubetarum], as I have said. ... These are the largest of all frogs, and have as it were a pair of horns, and are full of poison. Our authorities vie with one another in relating marvelous stories about the toad: that when brought into a meeting of the people silence reigns; that if the little bone found in its right side is let fall into boiling water, the vessel cools, and does not afterwards boil unless the bone is taken out... [Book 32, 24] There is a small frog, found living especially in reed beds and grasses, deaf, without a croak, and green, which, if it by chance is swallowed, swells up the bellies of oxen. ... Some put together into a new earthen jar fifteen frogs, piercing them with rushes; to the fluid that thus exudes they add the gum of the white vine, and so treat eyelids; superfluous hairs are plucked out, and the mixture dropped with a needle into the holes made by the plucked-out hairs. Meges used to make a depilatory for the eyelids by killing frogs in vinegar and letting them putrefy; for this purpose he used the many spotted frogs that breed in the autumn rains. [Book 32, 51] Salpe says that dogs do not bark if a live frog has been put into their mess. - [Rackham translation]

Augustine [5th century CE] (City of God, Book 16, 7): Frogs are produced from the earth.

Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:58): Frogs (rana) are named from their garrulity (rancare, “roar”) because they fill their native swamps with noise, and make their voices resound in unruly croaking. Of these, some are called aquatic frogs, some swamp frogs, and some toads (rubeta) because they live in thorn bushes – these are larger than all the rest. Other frogs are called calamitis, because they live among reeds and bushes (calamus, “reed”); they are the smallest and greenest of all, and are mute and without voice. [Book 6:59]. Agredulae are small frogs dwelling in dry places or in fields (ager), whence they are named. Some people claim that dogs will not bark if a live frog is given to them in a lump of food. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Worms 9.36; 9, 37): [Worms 9, 36] The frog, as the Liber rerum says, is classed among the worms. Its color is sometimes green and red, but of these the red is worse. It is talkative and annoying with its words. It fears that everything it breathes out will be suspected and hated by everyone [?]. In the month of August it can never open its mouth for any service of food or drink or voice, which if you try to open its mouth with your hand or stick, you will be able to open it only with difficulty. A frog has its own croaking voice, and it cannot utter anything other than this croaking voice, except when it is pressed or hurt: for then it changes its voice and emits a quick sound like a mouse. The cause for its croaking voice may be ascertained from this, as Aristotle says, that it sounds in the throat with the mouth closed and the sides inflated; but when it speaks it opens its mouth and pulls in its sides like a bellows, so that with a breath a stronger voice may come forth. It multiplies its voice when it places its lower mandible in the water and extends the upper one above; and when it stretches out both, its eyes shine like candles. Their copulation takes place more at night than during the day, and in this the modesty of copulation is signified. This is unlike those who indifferently and impudently come together during the day as at night. There is a great delay in the copulation of the frogs, and they emit a great deal of seed. A male frog calls a female frog by a voice known to her. The sea has frogs that have wings. Every fish feeds its young, except the frog. By this it is noted, from the sayings of Aristotle, that the frog is a fish. The tongue of a water frog, if placed on the head of a sleeper, makes him talkative in his dreams and reveals secrets, as in the dubious tale the old country people tell. [Worms 9, 37] There is a frog called by Pliny a rubeta, which lives both on earth and in water, and is filled with many medicines. These, as the Liber Kyrannidarum says, dwell in dry lands. Burnt ashes of these sprinkled in the bath remove body hair. It expels its drugs and takes them back when it wants, and is said to do this constantly during feeding. But it never lays down its poisons, but reserves them as weapons. With their flesh on the hook it is sure to attract the purple-fish in particular. They have twin horns full of magic. The authorities compete to tell of these wonders; they say, that if the bone of the right side of a frog is put into boiling water, the vessel is cooled, and will not boil afterwards until it is free from the rubeta. The remedy for the poisons of the sea-hare and the rubeta is their ashes drunk in water. [Worms 9.38] There is a small frog, as Pliny says, living chiefly in reeds and grasses, mute and without a voice, green, and if by chance it is sucked up by oxen, the oxen's bellies are distended to enormous fatness. [Worms 9.39] There is also a small frog known as corriens [running]. It climbs the trees and rests there among the leaves. It is a natural omen of the rain in the clouds, and sensing this it cries out loudly, as if with the news of a future flood, but during the rest of the time it hardly ever sings. The common people think that by throwing this frog into the mouth of dogs, the voice of the dogs will be silenced. This frog is green and small. - [Badke translation/paraphrase]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book18.90): The Frogge is called Rana, and hath that name of noise and crieng of his voice, for he cryeth gréedely, and maketh much noyse in the marreys where he is bred, as Isidore sayth, libro. 12. cap. tercio, de Piscibus. And some Frogs be water Frogges, and some bée of moores and of marreys, and some bée called Rubete, of whom it is spoken before in littera Byde Buphone: & some be called Calamite, for they dwell among reeds that be called Calami, & other among shrubs and in réedie places, and be but little and gréene, & dumbe without voice. And some be called Agredule, and be small Frogs, and dwell both in lande and in water, & have therefore that name Agredule. And ther is a manner Frog that maketh an hound still and dombe, if he commeth in his mouth: But many men deny this, as Isidore sayeth, libro. 12. And libro quarto, Aristotle saith, that the Frogge hath his owne tongue, & the further part of the tongue joyneth to his mouth, as though it were bound thereto, as the utter part of the tongue of a fish, though the hinder part and inner of the tongue bee loose and slacke toward the wosen: and therefore the Frog hath his owne voice, and that voyce is called Coax, and maketh not that voice but onely in water: And properly the male in time of love, when he crieth for the female. For every beast that hath voyce crieth in time of love, and the Frogge multiplyeth his voyce when he doth his neather jawe some deale in the water, and striketh the upper jawe, for by the strength of stretching of the two jawes, his eyen shineth as a Candle, and namelye by night: for he gendereth more by night then by day, and all fish nourisheth and féedeth his brood, except the Frogge, as he saith li. 7. when he is first shapen in water, the frogge séemeth all head, with a manner string, hanging as it wer a taile, & afterward is spread abroad in the manner of a womb, & then the taile is away, & then groweth féete: and he is shapen & turned into a foure footed beast. Al frogs, except the Toad, and Rubeta, move more, and passe by leaping more then by going, for the olde Rubeta leapeth but seld. Then the Frogge is watry and moorish, crieng, and slimie, with a great womb, and speckled there under, and is venimous, and abhominable therefore to men, and most hated, and both in water & in land he liveth. - [Batman]