The shepherd of frogs recognises the limping one.

What it means
To a stranger, the frogs all look like they are limping. That is just how they hop. Someone who has spent time with them can tell which one really does. Close, patient attention gives a kind of knowledge nothing else can.
Fulani · West Africa
Source and context
From: Fulani, West Africa
Source: Fulani/Fulbe oral-tradition proverb, documented in "Ten Fulbe Proverbs You Should Know" (nigerianpeoples.wordpress.com), consistent with the broader corpus discussed in "Proverbial Lore and Word-Play of the Fulani" (Africa, Cambridge University Press) — shepherd of frogs entry The source gives the saying with its own explanation: "a layman thinks they are all limping".

The source explains it: a layman thinks they are all limping. The wording of the meaning is ours.