Street dogs, known in scientific literature as free-ranging urban dogs or urban free-ranging dogs, are unconfined dogs that live in cities. They live virtually wherever cities exist and the local human population allows, especially in the developing world and the former USSR. Street dogs may be stray dogs, pets which have strayed from or are allowed freedom by their owners, or may be feral animals that have never been owned. Street dogs may be stray purebreds, true mixed-breed dogs, or unbred landraces such as the Indian pariah dog. Street dog overpopulation can cause problems for the societies in which they live, so campaigns to spay and neuter them are sometimes implemented. They tend to differ from rural free-ranging dogs in their skill sets, socialization, and ecological effects.
Outbreaks of rabies are often traced to unvaccinated street dogs, one of the most common carriers of the painful and deadly disease.
To survive, street dogs need to avoid conflict with humans. However, dog bites can occur when dogs are trying to mate or fighting among themselves, and pedestrians and other humans in the vicinity may be bitten by fighting dogs. In addition, females with pups are often protective and may bite people who approach their litter.
Barking and howling and dog fights over mating among dogs can be very disturbing to people, and the smell of dog urine which is an unsavory product of territory marking can become quite pungent, especially among unspayed or neutered dogs, not to mention the presence of feces.