Dog Profile: Dog is one of the earliest domesticated domestic animals, belonging to mammals, Carnivora and Canidae. Biologists believe that dogs were originally produced by natural hybridization between wolves, foxes and jackals. After long-term domestication by different methods, various ethnic groups have gradually formed a wide variety. According to United Nations statistics, there are about 500 million dogs in the world, and there are about 654.38 billion dogs in China. [br/] Dogs have always been friends and right-hand men. From border patrol, drug control, solving crimes, saving lives to guiding the blind and accompanying their owners, it can be seen everywhere. Because of this, dogs are loved and protected almost all over the world. All kinds of dog associations are spread all over the world, and there are also many service organizations specially set up for dogs in western developed countries. In the past, in order to control the threat of rabies to people, China once implemented the policy of killing dogs. With the development of economy and the progress of medicine, rabies has been well controlled by vaccination. Therefore, in recent years, major cities have gradually changed the inhumane practice of blindly killing dogs in the past, and formulated a series of more objective and reasonable dog-raising rules and regulations, which has gradually made China's dog-raising cause scientific and legal.
Second, the dog's life habits:
1: Digestibility: Dogs belong to Carnivora in animal taxonomy. The ancestors of dogs mainly preyed on small animals and occasionally used tubers to satisfy their hunger. After dogs were trained by humans, their eating habits changed and they became mainly meat? Omnivores, but vegetarianism can also sustain life.
2. Physique and anatomical structure: There are many kinds of dogs, and the difference in physical size can reach more than 20 times. The tallest dog can exceed 1 m, and the shortest dog is only 20 cm; The heaviest dog 130 kg. The lightest dog is only 1.5 kg. Although dogs differ greatly in physique, their anatomical structures are basically the same. Dogs have 225~230 bones, which not only constitute the dog's body? A solid support system can protect the internal organs and is also the basis for fast running.
3. Sensory function: The olfactory sensitivity of dogs ranks first among all animals, and its olfactory sensitivity to acidic substances is tens of thousands of times higher than that of people. ? The olfactory organ of dogs is called olfactory mucosa, which is located in the upper part of the nasal cavity and has many wrinkles on its surface, which is about four times as large as that of humans. Olfactory cells in olfactory mucosa are real olfactory receptors. There are about 200 million olfactory cells in olfactory mucosa, which is 40 times that of human beings. There are many thick villi on the surface of olfactory cells, which enlarge the surface area of cells and increase the contact area with odorous substances. Odor substances reach the olfactory mucosa with the inhaled air, which excites olfactory cells and diffuses to the olfactory nerve center-olfactory brain along the densely distributed olfactory nerves in the mucosa, thus producing sense of smell.
4. Amazing intelligence: Dogs have strong intelligence, can understand people's language, expressions and gestures, and sometimes do amazing things. For example, through training, I can count, read and so on. ?
5. Personality and expression: Like human beings, every dog has a specific personality. Some dogs are lively and clever; Some dogs are quiet and obey orders; Some dogs are violent and like to fight; Some dogs are timid and slow to respond. It is of great significance for the selection, training and breeding of dogs to accurately grasp the personality characteristics of each dog.