It's one of those Hollywood rules: don't kill the dog! The apocalpyse, cannibals, zombies, Furyans - if you're a cute, little doggy, you'll be fine (exceptions prove the rule).
The following Riddick clip adheres rather adoringly to this rule.
Without much further ado, here comes Riddick's possibly most tender moment:
After having seen this clip, you might want to argue that the creature saved by actually is some sort of space hyena. I won't disagree. But it's an extremely cute space hyena.