I wouldn't want to get close to a living crocodile unless it was in a zoo; they are dangerous creatures, who I think would rather snack on me than make friends. So when I first heard of Pachome riding on the back of a crocodile, I thought of the story had to be embellished -- to show the goodness of the saint. I had trouble believing it was literally true.
Then I came across the story of a Costa Rican fisherman who rescued a crocodile that had been shot in the eye and left to die. They developed a friendship that lasted more than twenty years, until the croc's death.
Click on this video link to see the fisherman swimming with his friend, the crocodile: https://www.youtube.com/watch?feature=player_embedded&v=tlz6iNw0Qes
Who knows, maybe Pachome did a good deed towards his crocodile too... one that earned him the croc's love. Or maybe the croc just recognized Pachome's goodness, and returned it in kind.