Fridge / Spirit: Riding Free

• Why is Spirit surprised about being captured by humans? Because this is not the Spirit from the first movie! This is Spirit's son. And why is he easier to tame than the first Spirit? Well, think about Rain for a moment. What was her life like before meeting Spirit? A domesticated horse raised by a gentle person. It's possible Spirit the second gets these tame traits from his mother.
  • In that case, Rain could simply have told her son about the humans, and in that way the Spirit in the tv show has something to expect when being confronted with them, unlike his father. The ability to be tame or be tamed easier is not genetically inheritable; this is taken further when you realize the Spirit in the tv show was presumably wild for his entire life before the show began.
    • Tameness is absolutely genetically heritable, though. That is why breeding plays such a large role in domesticating animals (like the Russian domestic fox experiment). It may be more accurate to call it docility or friendliness. In context of the show, Spirit could have been both taught by his mother and be more naturally trustful than his father.