User blog comment:GeneStarwind/Sand Barioth discussion./@comment-3250959-20101206161944/@comment-81.129.165.176-20120608105238

Barioths moved into the desert at night-time, when it is cold in deserts. They first hid away at day, only coming out in the cold night. Over time, they adapted to manage the heat of the day time better and no longer had to be nocturnal. Simple!