Wiktionary
n. 1 (context idiomatic English) A system used by primitive cultures in remote tropical regions for communication over long distances, such as drum sounds or a relay of runners. 2 (context idiomatic English) A gossip network; an informal communication system within a group or organization.
Usage examples of "jungle telegraph".
The idea that Norman might find out the address of her room on Trenton Street as the result of some cops' jungle telegraph had a sort of persuasiveness to it, but this was not the main reason he kept quiet.
He could hear his heart pounding wildly like some form of jungle telegraph.
I know what I know, in other words, I heard it through the grapevine, I got it on the earie, dearie, I picked it up on the jungle telegraph.
On an island this size, the jungle telegraph is like the Internet: all users are equidistant.