The Last Dogs by Christopher Holt

This is the first book of a series, but it makes a good story on its own.  It opens with a dog shut in a kennel for days.  For some reason, all people have disappeared.  If he doesn't escape, he will die.  Luckily, he meets up with a charming, if somewhat lazy, dachshund.  Convinced that an old black lab has the answers they need, the dogs set out on their own. Together, the two strive to find their missing people.  During their journey, they must battle a pack of hungry wolves, escape a group of militant dogs, and survive countless hazards.  The ending is wildly exciting, but of course, they haven't found their people.  It is a series, after all! A good read, this book might be challenging for young readers.