There is an entire section of our FAQ devoted to the subject of lions and heraldry. If you have any further questions after perusing these topics, you might consider pinging the user(s) who answered those questions for further information.
One thing to keep in mind is that lions existed in the area we now know as Europe during historical times, so they may not have been as exotic as one might think.
Edit: In order to comply with the wise and all-knowing AutoMod, I looked more closely at the FAQ threads in order to find a specific user or two to suggest you ping. Unfortunately, I'm now a little worried that most of the answers in these threads would not pass muster in the more modern (and rigorous) /r/askhistorians, so hopefully someone with some knowledge can provide greater information.
To add to this, have many Muslim cultures in the Middle East ever adopted animals as heraldic symbols? And if not, why? The only one I really know of is the lion of Persia.
Hi, there's an answer by u/MAGolding and links to a few previous posts here