The dog will know that he has been abandoned when he cannot see his owner. At first, he will not eat or drink, his eyes will be dull, and his body will tremble. After that, he will look for his owner on his own. The dog will only recognize one person in his life. Owner, so after being abandoned, there will be a big psychological shadow, and he will be full of fear of the humans around him. When there is a new owner, it will be difficult to get close to him, and he will need to spend more energy caring for the dog.