Choosing the right breed for you is not the easiest task. It’s important to understand each breed group so that you can really understand what your dog is pre-programmed to do. Looking from this angle, it allows you to choose what you are willing to accept and work on when bringing a dog into your home.
The look of the dog should not be terribly important. The natural instincts and behaviours that are bred into these dogs is what you are going to be living with for the next 7-18 years.
Terriers are working dogs in a small bodies, generally speaking. They are bred for hunting vermin and varmints ranging from rats to badgers to otters and more. They are energetic, tenacious, often vocal, and independent. Their high energy and need for “work” can often frustrate a low-energy guardian. Punishment-based training often backfires with terriers and results in bites. They are not known for their “soft mouths”, shall we say.
Toy dogs were bred to be companions for their humans. This does not mean that they are lazy and compliant, it simply means that their instincts may not be as intense as with other breed groups. Some toy dogs are very vocal, however, this is generally as a result of the guardian believing that they don’t need as much (or any) training due to their size. Toy dogs need just as much training as any other dog – they are still dogs after all!
Working dogs are powerfully built and intelligent, performing various tasks for humans. These dogs are bred to guard homes and livestock, serve as police and military dogs, security dogs, guide and service dogs and hunters. There is a wide variety here. These dogs are not generally best for first-time dog-guardians. They are high energy, intense, sometimes suspicious of strangers, not known for their natural sociability, and require a great deal of exercise and mental stimulation, plus a TON of positive conditioning to strangers (both human and dog).
Sporting dogs are bred to aid in hunting upland game birds or waterfowl, performing at the direction of the hunter. Some sporting dog breeds are bred to perform more than one task, but pointers and setters are bred to point and mark game; spaniels are bred to flush game; and retrievers are bred to recover dead and wounded game. Pointers/Setters/Spaniels are much like Working dogs and can be intense, difficult to control in a city environment, and prey-driven towards small animals like squirrels and birds. Retrievers tend to be a little easier in comparison. They are all high energy with a requirement for adequate exercise and mental stimulation.
Hounds are bred to hunt quite independently from their humans. The humans usually followed on foot or on horseback as the hounds chased down the prey. This makes them incredibly independent and somewhat more difficult to train. Some hounds can be very vocal (think of Beagles baying/howling) and others (Greyhounds) can be very quiet. These are dogs who are not generally ideal for dog parks or off-leash hikes where they can escape when something small catches their eye. Scenthounds follow their nose, sighthounds follow their eyes. It takes work to motivate them with other reinforcers (food, tug, play, access to resources, etc.) but it can be done if you can get creative.
Herding dogs are bred for work on farms and ranches with the sole purpose of gathering and moving livestock from one place to another. Many herding breeds are intense, high energy, vocal, and difficult to tire out. It is not surprising when these dogs circle and nip children when they are getting ready for school, or circle and bark at other dogs playing in the park. They often feel stressed when their humans separate (one goes upstairs and one goes downstairs, for example, or one goes into a store while one waits outside with them) and are prone to compulsive disorders (light-chasing, spinning, etc) as a result of genetics and/or lack of appropriate stimulation.
This group houses every breed that is left, resulting in a wide variety of sizes, shapes, function and history.