The definition of aliens/extra terrestrials should not be limited to the kind of beings we are, carbon life forms, that is.

Scientists and space explorers have been diligently looking for carbon life forms that also rely on water to survive, which is why they get so excited at finding out Mars used to or still does have water / ice on them.

Aliens for all we know, could be other life forms such as nitrogen? No such thing exist on earth does not mean it cannot exist on the other gazillions of planets out there. Though there is no prove on my argument, there is nothing to prove it otherwise as well. I'm just saying that people, especially scientists and researchers need to be more open minded to all the possibilities there is.

Alan, I understand what you're saying, because it is tedious and maybe potentially pointless to look for something that may or may not be there.

However as researchers they have their better ways of searching for things. Taking your example as an example: I can't find any tigers in the jungle, so I check with my fellow researchers: Eh your team checking the desert rite? Found anything interesting? What? Found a tiger-lookalike being/creature roaming around there?

It is not a 1 man show or a single person effort, researchers and scientists work closely together (not talking about rival countries or whatnot) and they often share their findings.

I'm just speaking as a normal person, but logically thinking, scientists DO share their findings with their fellow researchers especially when it's a joint venture/cumulative effort.