Proverbs are stable expressions that can very accurately and expressively characterize any phenomenon. Their appropriate use adorns speech. But the use of proverbs without regard to meaning can play against those who decide to show off erudition.
Meaning “Raven will not peck out the crow's eye”
There are two interpretations of the proverb “the raven will not peck out the crow”:
The first is that immoral people will easily find a common language and will always be able to agree on the observance of common interests.
The second - people who occupy one position in society according to their social status will not quarrel with each other, but unite against a stranger.
It will be erroneous to consider that the proverb is talking about friendship.
The origin of the expression
The proverb has been known since ancient Rome. In those days, knowledge was obtained empirically. So, in the process of observing crows, it was noticed that they needed a powerful beak and claws to hunt for prey, and not to kill their own kind. In predatory species, fights for a female or prey with a fatal outcome are a rare exception. The usual outcome of the battle is a weak opponent takes the pose of submission, such is the protective mechanism of nature that exists to regulate the number of species. For ravens, it looks like this: a loser substitutes an unprotected nape to the winner. The highest form of trust in these birds is considered to clean feathers near each other's eyes.
This is where the meaning of the proverb “Raven doesn’t peck out the crow” comes from.
Full Proverb
A few years ago a post appeared on the net and spread about the forgotten sequels of famous proverbs, changing their meaning. So to change the meaning “the raven the crow will not peck out the eye” should be supplemented “he will peck, but he will not pull it out”. Interpretation of such postscript that there will be no winner in the struggle of these birds.
The post became so popular that there were requests for a full version of the proverb in question. Its original, in transcription into Russian from Latin, is reproduced as Cornicorn of the Corniche Nunquam confodit oculum. Comparing the number of words, one can understand that in the Roman version the proverb did not have a continuation.
In the collection "Proverbs of the Russian people" compiled by folklorist Vladimir Ivanovich Dahl, in the section "Friend is an Enemy" the following entry is written: "The raven will not peck out the crow's eye." A synonymous replacement “Flea does not eat flea” is attributed nearby. Therefore, the assumption that the supplement was born during testing in a new language will be incorrect.
By correlating these two facts, we can conclude that the full version of the proverb is nothing but falsification.