How many kinds of dogs are there?

Dog, commonly known as "dog", belongs to Carnivora Canidae in animal taxonomy and is one of the earliest domesticated animals. Darwin believed that the ancestor of dogs was wolves, and it was the first natural cross between wolves, foxes and wolves. According to records, people have kept dogs for thousands of years. In the long years, people have carried out a series of breeding and breeding for dogs according to their own needs, will and characteristics, and finally cultivated various dog breeds with docile personality and capable of serving human beings. At present, there are many kinds of dogs in the world. According to incomplete statistics, there are about 400 species (some documents record 850 species) and hundreds of millions of dogs.

There are many kinds of dogs, with great differences in body shape, coat and personality. Tall dogs can reach 1 m, and short dogs only have 15 cm; The heaviest can reach more than 100 kg, and the lightest is only about 1 kg; The fastest dog can reach 100 km/h; The tallest jumping dog can jump over obstacles 5 meters high; The maximum litter size is 1, which can reach more than 20. Dogs have different uses, some are brave and tenacious, and can be used for hunting; Some wit and flexibility can help people work; Some are lively and lovely as spectators and companions; Some characters are stable and used as experimental animals; Some are big and fleshy, and the meat is delicious, so they are used as food dogs.