that's right. it's possible that it's his LEFT hand. after all, the pose is not impossible. check out this crappy quick doodle.
now you might wonder why croc used his left hand that way. well, there's only one explanation: he knows that the readers will only see him as a silhouette, so he decided to trick us into thinking that he did that with his right hand. the question is, what is his right hand doing? let's x-ray his back.
he's scratching his ass! which makes sense! he can't possibly scratch his ass with the hook!
I will have to agree, they were in the desert and I know from experience that sand gets EVERYWHERE.