There is an incredible variety of dog breeds today, with new ones emerging every year. In fact, it's estimated that there are around 800 breeds of dog, though only 150 of these are really widespread throughout the world.
DNA testing shows that dogs evolved from wolves around 15,000 years ago after humans began selectively breeding them. Today, there is probably no other type of animal on the planet that is so diverse in terms of appearance while still remaining a single species.
One dog breed can look totally different from another dog breed in different parts of the world - just compare a Chihuahua to a Great Dane, for example.
So why should any of this matter to any owner?
Because, besides coming in wildly different shapes and sizes, dogs also have equally diverse skills and temperaments, due to the aforementioned centuries of human-controlled breeding and selection. Their health requirements and vulnerabilities vary from breed to breed as well. These factors should play a significant part when you're choosing the right dog breed for you.
Generally, each dog breed will fall into one of several functional categories:
1. Companion dog
This type of dog was not bred for work or utility, but to act as a companion. While members of almost any dog breed can act as companions, it is generally accepted that the smaller, toy breeds are the most representative of this category, since they were specifically bred to carry out this particular function.
Popular dogs of this type include the Pomeranian, the Chihuahua, and the Pekingese.
2. Guard dog
A dog breed that falls into this category has been specifically developed to guard against unexpected or unwanted people and animals.
A watch dog barks to alert its owner to an intruder's presence; a guard dog goes further by attacking or restraining the intruder. Famous exponents of this category include the German Shepherd, the Doberman Pinscher, the American Bulldog, and the Bull Mastiff.
3. Hunting dog
These breeds were created to aid during hunting. The category can be further divided into these subtypes: hounds (sighthounds and scenthounds), terriers (for vermin and small mammals), gun dogs (retrievers, flushing spaniels, pointing breeds) and cur type dogs (for boars and raccoons).
Popular hunting breeds include the English Cocker Spaniel, the Whippet, the Golden Retriever, the Beagle, and the Scottish Terrier.
4. Herding dog
Also known as stock dogs, this category includes some of the most intelligent breeds. A dog breed of this type serves as a pastoral aid, herding sheep, cattle, and other livestock. They are well-known for their ability to be trained to respond to whistles or spoken commands.
Various breeds have been independently developed around the world, through the centuries. Some famous examples include the Border Collie, the Cardigan Welsh Corgi, and the Bouvier des Flandres.
5. Sled dog
These breeds, also known as sledge dogs or sleightman dogs, are used for transportation, capable of pulling sleds over vast expanses of snow or ice. They are renowned for their extreme endurance and speed.
Well-known examples include the Siberian Husky, the Alaskan Malamute, and the Samoyed.
As you can see, there is a huge amount of variety in this single species. When selecting a dog, do some research about the breed's temperament and overall health outlook.
In general, larger breeds tend to be especially prone to hip dysplasia, while small dogs tend to suffer from knee cap dislocation.
Dog breeds with deep chests, including Basset Hounds, Labrador Retrievers, and Great Danes, tend to be susceptible to bloat. Meanwhile, dogs with "snub" faces (brachycephalic breeds) such as the Pug, the Pekingese, the Shih-Tzu, and the Bulldog, are prone to problems with their breathing and eyelids, susceptibility to heat stress, and dental problems.
Take everything into consideration when choosing your pet, and don't just go on looks alone. Knowing the unique traits of your dog's breed will better prepare you for a fulfilling and happy life with your chosen companion.