Er ist auf DEM Kamel geblieben (dative). I think you're referring to the perfect tense, where the rule generally is change in position or condition for using sein vs. haben. Er ist nach Hause gegangen=He has gone home (or He went home).
Bleiben is an exception to the change in position or condition rule, as is sein. E.g. Er ist zu Hause gewesen=He has been at home (or He was at home).
I hear the female voice saying "Duo reitet auf seinem Kamele." I first reported it as an error in German, then as something wrong with the audio. Then I remembered that an "e" can be added to a masculine or neuter noun to make it clear that a phrase is in the dative. Finally, I remembered that this is seldom done in modern German except in fixed phrases like "zum Hause." In any case, the final "e" exists in what I hear, but not in what is written.