Although dog parks can be great fun for dogs, some dogs should not ever be taken to a dog park. The dog in the above photo is an example. In speaking with the owner, he indicated that his dog was fear aggressive to other dogs. His dog had attacked other dogs. He seemed to think that putting a muzzle on his dog protected the other dogs, while his dog could become more comfortable around other dogs. Unfortunately, bringing a dog who is fearful of other dogs around dogs is a really bad idea. First, it does nothing to help the fearful dogs adjust to other dogs. Second, he has placed his own dog at great risk of injury. If another dog approaches his dog, and his dog reacts, the other dog could easily grab his dogs muzzle, causing injury. The only way to deal with a dog that is fear aggressive is to work with a qualified trainer, who can figure out the best strategy to gradually expose the dog to other dogs in a controlled setting. I once owned a dog who was a fear biter. She was enrolled in a highly structured behavioral training program. We would sit with the dog, giving her a favorite treat, while an assistant walked a dog at some distance from our dog. When the dog appeared, our dog would be given a treat and praised for not reacting. There was a slow process of gradually decreasing the distance between our dog and the assistant's dog, using treats and positive feedback to keep our dog calm. Eventually, our dog was able to be close to other dogs without reacting. Even then, I would never have considered taking her to a dog park and letting her run loose. Aggressive dogs, or dogs who are afraid of other dogs or people, are not dog park dogs.

Then there are the people who may be bringing a newly rescued dog to the park, just to see how they will react. Which is another bad idea, if you don't know the dog, and know that it is well behaved, don't take it to the dog park. This is to say nothing of a person who once came to the dog park with her five rescue dogs and some sort of parrot type bird on her shoulder. The bird made noises like a squeaky toy. Her dogs may be used to the bird, but another dog may try to catch it and kill it. There should be a sign at the entrance to every dog park: "Common Sense Required to Enter Park."