There is a breed of dog that can climb trees, flex its spine like a cat, and use a singing howl instead of a bark.
It is known as the New Guinea Singing Dog, named for its unique howl. Presently, almost nothing is known about them in their native habitat. No photographs even exist of them in the wild. These dogs are often kept as companions because of their intelligence and physical abilities.
Like coyotes and wolves, these dogs often howl together in what is called “chorus howling.” Most of the time, the dogs howl with very good synchronization and end at the same time. Their legs and paws are much more flexible than regular dogs, to the point of being able to climb trees, albeit not as well as a fox or cat. Because of this, they are notorious escape artists.
They can climb and jump like a cat, and even get over fences as easily as squirrels. Though they generally avoid people and aren't very easy to domesticate, they're still quite a spectacle.