Dogs and parks. Wed two of our favorite things together and you have the makings of a perfect day, right? Except at America's national parks. Save for a few exceptions, dogs are never allowed on national park trails and rarely permitted beyond a campground or picnic area.There is an old saying that goes, "Start explaining and you've lost the argument." The National Park Service goes to great lengths to explain their reasons for banning dogs outside of vehicles. Dogs endanger wildlife. Dogs interfere with people's enjoyment of the park. Dogs ruin the pristine environment. Dogs can introduce diseases that could decimate wild populations. Some parks citethe fact that just the scent of dogs will make prey animals frantic (at least that will keep the jittery critters out of campgrounds and picnics where apparently their wellbeing is not as big a concern).Some park officials go so far as to imply that they are doing dog owners a favor by keeping dogs out of the woods since they may become prey themselves. One park's regulations read thusly: "There is a strong possibility that your pet could become prey for a bear, coyote, owl, or other predator." What is a "strong possibility?" Better than 50%? 20%? Really? Any talk of the probability of a leashed dog on a trail being eaten by a wild animal that goes beyond "vanishingly small probability" is absurd.Tellingly, the national parks in Canada - which also receive millions of visitors each year and also protect wildlife - allow dogs on their trails almost without exception. And in the United States the prohibition against dogs on national park trails is not a universal edict. Individual parks are allowed to make their own rules regarding dogs. A handful have decided to allow dogs on the trails, the chance of man's best friend becoming some other animal's dinner be damned. Some have even become more lenient in recent years. Petrified Forest National Park used to allow dogs only on a few nature trails. Now the park declares: "Petrified Forest is a very pet friendly national park! Please take your furry friends on trails, even backpacking in the wilderness area."This is not a book about whether rules regarding dogs in national parks are right or wrong. It is about how dog owners - given the current restrictive playing field - can experience our national parks, take along their best trail companions, and still have their dream vacation. For each park, if dogs are not allowed on the trails, a nearby substitute is identified and described (dogs are usually welcome in national forests, for example. The burden on people and wildlife caused by dogs and a patronizing concern for a dog's well-being apparently cause less government worry in those woods). Only those national parks which can be reached by automobile are included.So with that in mind - grab a leash and hit the trail!