Dog parks -- Disclaimer: I hate them -- for some of the same reasons you described. The free-for-all environment is a horrible place for a maturing RR to learn social behaviors. Horrible. Did I mention I hate dog parks? I could write pages on why dog parks aren't appropriate places for Ridgebacks. In short, a young RR who is learning to be pushy with other dogs (a bully, really) is eventually going to come across an adult dog who will not be as tolerant of things like neck-grabbing, body-shoving, and humping -- and that's when the pushy dog is going to get hurt. Ridgeback males tend to take it another step and then ramp up their pushiness in future situations, so they are putting themselves at risk for all-out dog fights. I've seen it repeatedly -- the previously sweet boy goes to the dog park, then "suddenly" becomes dog aggressive, when in fact, it hasn't been sudden at all. All these things add up to create a dog whose behavior is unacceptable.
I apologize if this sounds blunt. I don't have tons of time to write this evening, but if you've other questions or you feel like I'm not understanding the behaviors you wrote about, please let me know.
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