Kevin Hart struggles to keep his fear in check as Robert Irwin, 14-year-old son of Crocodile Hunter Steve Irwin, brings out some interesting animals to show him and Jimmy, including some kingsnakes, a tarantula and a falcon. Subscribe NOW to The Tonight Show Starring Jimmy Fallon: http://bit.ly/1nwT1aN Watch The Tonight Show Starring Jimmy Fallon Weeknights…