Abstract: Feral or free ranging dogs are wild or semi-wild dogs and their offspring who wander in variable types of environments due to the unintentional loss or deliberate abandonment of their hosts. Due to historical and cultural reasons, the population of feral dogs in Tibet keeps increasing. In this paper, we analyzed the negative effects of feral dogs on the natural eco-systems, including carrying and spreading viruses, bacteria and parasites, injuring livestock and poultry as well as humans, threatening the survival of wild animals, affecting ecological balance and increasing the environmental pressures. According to the actual situation in Tibet, we made prevention and control suggestions as following: strengthening census and investigation, implementing population control, increasing investment in scientific research, strengthening social education and legislation, and protecting local wildlife adjusted to time and location.

Key words: Tibet, free-ranging dogs, damage, prevention and control