Today, the urban environment imposes restrictions on dogs, which need space to move. The chance of dogs living a vagrant existence increases greatly in big cities, where garbage piles up but is not easily cleared away, enhancing the chance for abandoned dogs 'survival. This is one of the reasons why impoverished nations have similar amounts of stray dogs as advanced nations.
今天都市居住環境限制了需要活動空間的狗兒，狗兒流落街頭機率大增；大都市垃圾集中、市容不易管理，又增加棄犬求生機會，這也是貧窮國家流浪犬數量不下先進國家的原因之一。