Liam Aiken was given his own Italian greyhound puppy (which he named Kes) as a gift for working on the film. It was to be presented on his last day of filming, but was withheld until the end of the day as his saddest scene was to be filmed on that day and the crew didn't want him to be happy.
If dogs have a planet where they are the rulers, and humans have never been in control, than that planet can't possibly have anything like pugs or chihuahuas. These and other "toy" breeds can only exist because of inbreeding and genetic engineering directed by humans, in a manner that goes against the natural course of canine nature.
When the household moving trailer is full and the rear doors are closed, the latches are still open. In the next few shots, the latches are closed, and then open again.