Animals can be in equilibrium the entire ecosystem of the planet
From the very childhood loved the different animals, especially cats and dogs. I often remember with a smile, as I was playing with a puppy grandfather, as I took care of his kitten (which is now a huge and vymahal solid Koshak). It gives me very great pleasure to the process of interaction with pets, but Che really must admit, I still get nothing from this irreplaceable pleasure.
I think like many other people who are constantly interacting with baby animals, there was a question: Why are we so good if we are the guardians of your pets? What gives us such pleasure in dealing with them? And, in the end, is there from what-is the practical use?
To answer this question, we must look at the history of domestication of wild animals by humans. That is, to find the cause and the domestication of forest / steppe / mountain beasts order to turn them into docile and gentle animals.
The first animals that were domesticated were dogs. Not exactly a dog, as such, and wolves. How is it that carnivorous animals do not hesitate to join the Homo sapiens? There is a theory that wolves consciously settled next to the man, because the majority of their diet they received from the remains of human food. A man then this neighborhood too, is useful because it scared off wolves and other predators, and warned of the approach of enemies. A kind of symbiosis of humans and wolves. Like, we'll eat, you give us protection. And this system worked. Over time, the wolves began to change, they become more playful, they have learned to bark, as well, there have been large and physiological changes. In the last few centuries, the people began to hold an artificial selection, in order to derive certain breeds of dogs, for specific economic and social needs .... This is how the Bulldogs, the Russian Borzoi, Dobermans, German Shepherds, and so the list goes on ..
With cats, it must be said, a similar story happened. Initially, they settled near the warehouses and granaries, as these areas were most attractive to all kinds of mice and rats, in which they, in fact, were hunting. By the way I will add that in those days (and even now, too), mice, eating edible stocks have a tremendous economic damage to the whole state. It would be logical to assume that people in those days, considering the potential of cats, as defenders of rodent pests, were specially fed them, in order to attract a larger number of cats to the warehouses and homes. And then, as they say, off we go .... Now the world is home to over 100 species of domestic cats (plus various hybrids).

In addition to the economic role, pets still play an important social role (well picked a bad adjective :)). I think everyone has heard the saying, which states that a dog is man's best friend. Apparently, the way it is. As I mentioned above, dogs are descended from wolves, and wolves, in turn, the animals group, with a very developed system of relations in his pack. Now, these qualities have got and dogs. Dogs are wonderful animals in general. They like to spend time with the people they enjoy playing with the kids (and not only). They love and respect their host. Moreover, dogs can feel human emotions. They are able to empathize with the person. They can take care of the person to worry about it!: If the dog is afraid of water, he will be doing everything possible that would not have to resort to the water rights (from my own experience, I know when a dog grandfather was trying to block our way to the river in the country, as we went to swim, because the river itself is terribly afraid. Interestingly, she still overcame his fear when she saw that someone drifts too far. she rushes off in pursuit, overtook, overlapping way and all their actions trying to get people to swim back to the shore).