A fox is a reference to a clever person and the snare denotes a mistake or pitfall. A clever person does not make the same mistake twice as he quickly learns the lessons from his past mistakes.
One who learns from his mistakes does not repeat them. because once bitten, twice shy.
Another way to express the same idea is the proverb:
Fool me once, shame on you,
Fool me twice, shame on me!
This proverb emphasizes the importance of being aware of potential pitfalls and being cautious, especially if one has been fooled or tricked before.
It originated from a Latin proverb, “Vulpes non capitur bis in eadem laque”, which was first recorded in the 12th century.