History of All Cloven-Hoofed Quadrupeds

Why horns were given to animals.
3. de part. 2.

...the Indian [ass]: for it is both one-horned and solid-hoofed; and the Oryx is one-horned and also cloven-hoofed. It will therefore not be outside our purpose to teach for what end Nature has bestowed horns upon them, and what their matter and diversity may be. For if they did not have horns, they would be exposed to the injuries of many other animals (although they are also a hindrance to some). Whence the Philosopher said: Those which are not viviparous lack them. We say that certain other things have horns, but only by similarity and metaphor, since none of them performs the function of a horn. For those that bring forth a live animal bear horns for force, either to inflict it or to repel it, which does not happen to any of the others that are said to have horns. For none uses horns either for overpowering or for defending, which are the duties of strength. Therefore, all those that have multifid feet lack horns; the reason for which is that a horn is possessed for the sake of aid. But other aids are not lacking for the multifid ones.

Diverse weapons of animals.

For Nature gave claws to some, fighting teeth to others, and to others another part by which they might protect and defend themselves; but indeed the greater part of the cloven-hoofed bear horns, and some of the solid-hoofed, for the sake of inflicting force and some also for defense. However, for those to whom Nature did not give horns, she looked after their safety with other protections, as she helped some by swiftness of body, and camels by their size; for the abundance of size is sufficient to ward off death, as happens to camels, and even better to elephants. Some in the cloven-hoofed genus are also armed with a protruding tooth, like boars. For those whose horns are superfluous because of too much excess, Nature applied another aid, such as speed to deer. For that great and multifid magnitude of horns

To whom horns are useless.

is more a hindrance than a help. Horns are also sometimes useless to buffaloes and wild goats; for even if they resist some things and defend themselves with their horns, nevertheless they flee from fierce and pugnacious beasts. To the Bonasi (for they also gather their horns together in a circle with a similar hookedness) Nature gave a profuse discharge of excrement as an aid; for they protect themselves with this when they are afraid. It is certain that others also are saved by this same discharge. But Nature has granted to no one many aids at once, of which each one would be sufficient. There exist truly golden verses of Phocylides upon this matter, which it would be a sin to keep silent:

Ὅπλον ἑκάστῳ νείμε θεός, φύσιν ἱερόφοιτον,
Ὀρνίθεσσιν πολλὴν ταχυτῆτ', ἀλκάν τε λέουσι.
Ταύροις δ᾽ αὐτοχύτοις κεράεσσι, κέντρα μελίσσαις.
Ἔμφυτον ἄλκαρ ἔδωκε, λόγος δ᾽ ἐρυμ᾽ ἀνθρώποισι.
God distributed a weapon to each, a divine nature,
Indeed great swiftness to birds, and strength to lions,
And to bulls horns born of their own accord, and to bees stings,
He gave an innate defense; reason is the rampart for mortals.

What it is to "raise horns."

Since, therefore, horns were made by Nature both for defending and for offending, we proverbially say that a person "lifts his horns" for that which is to be carried away by pride, doubtless from the epodes of Horace, where he says: For against the wicked, most fierce, I lift my ready horns. Somewhere else again concerning Bacchus: And thou addest horns to the poor man. In which sense Ovid, speaking similarly of drunkenness:
Then comes laughter, then the poor man takes up horns.
And to this belongs that saying of the Greeks: πρὸ τούτου σ' ᾤμην κέρατα ἔχειν, that is, before this I thought you had horns.

What it is to "turn horns toward."
In Pseudolus.

But those who are ready to repel an injury are said to "turn their horns toward," in which sense Plautus says:

By Pollux, I never saw any man worse or more
cunningly evil than this one is;
and I fear and dread that monkey of a man badly,
lest he be as evil toward me as he was toward him.
Lest in prosperity he now turn his horns against me
if he should seize an opportunity, he who will become wicked.

Most elegantly and at the same time most facetiously, the metaphor being taken from here, the poor man Euclio rejects the wealthy Megadorus—treating himself as a despised little donkey, but the rich Megadorus as a bull, as if boasting in his own weapons and threatening to be his future son-in-law—while he says:

This came into my mind, Megadorus, that you are a wealthy man
of high standing; and likewise that I am a poor man, the poorest of the poor.
Now if I were to bestow my daughter upon you, it comes into my mind
that you are the ox, and I am the donkey; when I should be joined with you,
when I could not bear the load equally, I, the ass, would lie in the mud;
you, the bull, would no more look back at me than if I had never been born,
and I would find you more unjust, and my own rank would mock me;
in neither place would I have a stable stall, if any separation should occur;
the donkeys would tear me with their teeth, the bulls would charge me with their horns.

What it is to "attack a horned beast."

There exists also in the Comic poet a proverb in this sense: You are attacking a horned beast, concerning one who provokes...