Gumption!

Peter's been invited to go on a safari. He's brought:

1. Uncle Nigel, who's an explorer

2. hiking shorts

3. a canteen

But what he will need most is a bit of gumption.

(Gumption: n. Courage; spunk; fortitude; resourcefulness; good sense.)

Oh, wait...there are crocodiles in the river? Then he might need a lot of it!