In the Hunger Games movie, Cato fell off the cornucopia after his final showdown with Katniss and was victim to the horrible dog-like muttations. Pitying the boy, Katniss immediately shot Cato ...

It makes sense that the Hunger Games movie would change Thresh's death since it also cut the brief scene of Cato finding Clove. Without this moment, Cato doesn't have as much motivation to go ...