I have a toy poodle, Shadow. She's a little whippersnapper! And I love little monkeys.
I got quite annoyed after the Haiti earthquake. A baby was taken from the wreckage and people said it was a miracle. It would have been a miracle had God stopped the earthquake. More wonderful was that a load of evolved monkeys got together to save the life of a child that wasn't theirs.
Cats and monkeys; monkeys and cats; all human life is there.
I like animal sidekicks. They seem to be a pretty cool trope of post-apocalyptic fiction - just because if you're going to have this lone protagonist, they're going to need someone to talk to. Dogs are overused, and cats are dumb. So that leaves monkeys.