[Théodore]

I already know it may be a silly or useless question, but I red somewhere that cliff riders lived only on Vvardenfell ; is that true ?

[gro-Dhal]

I don't think that's the case; they can fly after all. I think you'll find fewer of them in TR's maps because, well, they're annoying.

Where did you read that?

[blackbird]

There are no cliff riders in Vvardenfell, but there are cliff racers.

[Théodore]

Well, I red it just there : http://lagbt.wiwiland.net/wikibiblio/index.php/Braillard_des_Falaises [French website]

I know they are on the mainland, and that's precisely why I was asking that question here.

@blackbird:
Yes, sorry for the mistake.

[Ajif]

Cliff racers are only (true to lore) In Vvardnfell were as in the main land there are a species of strange almost netch releated flying jellyfish called Skylamps which killed the cliff racers in the main land.

[Thrignar Fraxix]

cliffracers didn't exist until the game morrowind was released. Skylamps magically stopped existing when morrowind was released. You can choose 2 explanations: That skylamps are cliffracers, or that the cliffracers killed off the skylamps with the dragons.

To quote TIL's bit on why there are no dragons in morrowind.