The global dog population is estimated to be 900 million and rising. Approximately 83% of these dogs live unrestrained. Although it is said that the "dog is man's best friend" for the 17–24% of dogs that live as pets in the developed countries, in the developing world pet dogs are uncommon but there are many village, community or feral dogs. Most of these dogs live out their lives as scavengers and have never been owned by humans, with one study showing their most common response when approached by strangers is to run away (52%) or respond aggressively (11%). Little is known about these dogs, or the dogs in developed countries that are feral, stray or that are in shelters, as the majority of modern research on dog cognition has focused on pet dogs living in human homes.
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