Trackers

Trackers are used by the Gamemakers in the Hunger Games to keep a record on a tributes whereabouts, state and/or if they're alive or not.

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In the Hunger Games movie, the trackers are inserted manually by a Capitol Attendant, while the tributes sit in the hovercraft's cargo bays. This is different to the book, whereby a current idolizes the tributes prior to sitting down and the tracker is inserted.

In the film, as Katniss is recieving her tracker, she is unsure as to what it is.

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In Catching Fire, Katniss is not shown to recieve her tracker, and it is not known whether or not she recieved it on the hovercraft.