To convey information.AND...
Because otherwise there is no need to communicate. If you don't want to communicate, why bother?
The theory of communication would have it that communication has only occurred when the recipient is aware of the message. In this sense, broadcast radio is possibly not communicating for at least...
you can always contact them via phone or emai9l but then it depends on what type of isolation their undergoing...
It is unknown if any animal species on earth communicat in a certain way ( like language not just nods and random noises).