Portuguese: quem nasceu para burro nunca chega a cavalo.
English: who was born to be a donkey never makes it to horse.
Lithuanian: asilu gimęs, žirgu netapsi; ar taip asilui dėsi kepurę, ar kitaip - vis tiek ilgos ausys matyti.
Meaning: it is impossible to hide the nature.
Portuguese: vale mais um burro que nos leve que cavalo que nos derrube.
English: a donkey that carries you is better than a horse that throws you to the ground.
Lithuanian: geriau asilas, kuris neša, negu arklys, kuris numeta; geriau žvirblis rankoj, negu erelis danguj.
Meaning: modestly, but safely; it is better less than nothing.
Portuguese: a cavalo dado não se olha os dentes.
English: don't look a gift horse in the mouth.
Lithuanian: dovanotam arkliui į dantis nežiūri; arklį gavęs, gaidžio negeisk.
Meaning: don't be too choosy when something comes to you without effort.
It was always interesting for me, why there are so many proverbs about donkeys and their foolishness, because they are really cute animals, in my opinion. Now I found that the same situation is in portuguese. What a pity! J