Why Don't Dogs Climb Trees?

You know the scenario: a dog is in hot pursuit of a cat.
The cat darts for the nearest tree and, in a flash, triumphantly stares down at the dog from a top limb with its tail twitching madly. Meanwhile, the poor dog runs back and forth at the base of the tree, eyes fixed on its prey, jumping and barking in frustration. So why doesn't the dog follow the cat up the tree? You see the occasional dog on the news or in an Internet video climbing a tree. A few breeds of dogs have a reputation of being able to climb trees, most notably Catahoula Leopard Dogs, Tree Walking Coonhounds, New Guinea Singing Dogs, and Jack Russell terriers. And you can never discount entirely a dog's determination and ability to adapt. If a dog wants the prey badly enough, he may climb at least a short way up the tree. Dogs have also been known to climb to low-hanging tree limbs to get over a fence.Dogs Just Aren't Built for Tree Climbing
Dogs ancestors tended to live in more open areas. They developed strong back legs for endurance, so they could travel across long distances. Since they needed to be able to run more than they needed to be able to climb, their legs typically don't bend around things, so they can't grab a tree trunk like a cat or even a bear. Additionally, dogs nails don't retract like a cats nails do. Dogs nails are thicker and may be stronger than a cats nails, but they are dull and can't penetrate wood like a cats claws. If a dog does fall from a tree, he's not as likely to land on his feet as a cat. One reason is because a dog's back isn't as limber so a dog can't go through the contortions a cat can when a cat rights herself before she lands.Dogs Were Trained to Put Other Animals Up Trees
Lastly, many dog breeds were bred to tree their prey, and just bark or bay until their owners arrived. For these dogs, catching the prey isn't the object of exercise, so there's no reason to try to climb the tree after it.