I dare say that the desert landscape and the visible ocean make it seem like the scene is set in africa, not the middle east, so the expected animals should be Cameli dromedarii, not Cameli bactriani. Curiously, the one at the far left has a hump visible in front of the position the person is sitting on - this does not, however, imply a second hump, as sitting just above a Camelus dromedarius'* gluteus maximus is common riding practice.
*With respect to readers not speaking latin, i refrained from declining Camelus dromedarus into genitive. Correctly it would have to be Camelus dromedarii.