Why do painted rays swim along with their nose out of the water?

It's possible that these stingrays were after food because they do tend to get fed a lot and they could have been sniffing around for that but there's also been thoughts that similar creatures to the stingrays which are the sharks, because they're quite closely related, might possibly have the ability to sniff the air. There was a study in Russia in 1994 about oceanic white tips which are quite dangerous sharks, not very dangerous but quite dangerous that go through open ocean. They were seen to sniff above the surface of the water, a similar thing in great white sharks. The scientists looked at this sensory part of their snouts and they think there is a possibility they were actually detecting scents in the air that would move more quickly in the air than in water. Volatile chemicals will disperse much more quickly so perhaps they were doing much better than their competitors at smelling things like dead whale carcasses that wouldn't be so smelly underwater.