New Delhi, May 3: Domestic dogs currently threaten across the world at least 188 species of mammals, birds and reptiles, including the Olive Ridley turtles, the Great Indian bustard and the hog deer in India, a team of international wildlife scientists has said.
The scientists have said dogs have already contributed to the extinction of 11 vertebrate species across the world and are now a potential threat to 94 mammals, 72 birds, 19 reptiles and three amphibians.
The researchers from academic institutions in Australia, India, New Zealand, South Africa and the US have published the study in the journal, Biological Conservation.
Their analysis suggests that the global impacts of domestic dogs on wildlife have been "grossly underestimated" with the number of species threatened nine times higher than earlier estimates.
An independent Indian study has indicated that dogs have also emerged as primary predators of livestock in Himachal Pradesh's Upper Spiti region where villages appear to be losing more sheep and goats to domesticated dogs than to wolves or snow leopards.
"These studies point to the need for strict rules for dog ownership and stronger, effective population control for dogs," said Abi Vanak, a scientist at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore, who was involved in both the studies.
Scientists believe the world has nearly a billion dogs, the majority of them in the developing countries where they are free-ranging animals, largely dependent on humans but at times also treating wildlife and livestock as prey.
Dogs have contributed to the extinction of the New Zealand quail and a reptile called the Cape Verde giant skink, among others, the researchers said.
In India, domestic dogs now threaten several already endangered species, including vultures, the tree shrew on the Nicobar islands, the Great Indian bustard in central and western India, the Olive Ridley turtles that beach on the Odisha coast and the hog deer in the Northeast.
Vanak and his colleagues who also studied patterns of livestock kills across 29 villages in the mountain landscape of Upper Spiti believe that growing tourism and inadequate disposal of food waste is increasing the population of free-ranging dogs and attacks by dogs on livestock.
The researchers who documented 441 livestock kills in 2013 found 280 (nearly 64 per cent) of these kills were by dogs, 126 (28 per cent) by snow leopards and 35 (8 per cent) by wolves.
"Local communities now see the dogs as companions that have turned against their source of livelihood - some are no longer keeping herds of sheep or goats," said Chandrima Home, a doctoral scholar at ATREE who spent more than two years in the area tracking livestock losses.
However, Home said, there is some evidence that dogs are now attacking bigger livestock and even some wildlife species.
During December 2014 and January 2015, Home learnt from local herders that dogs had killed the calves of larger-bodied livestock such as yaks.
The scientists have estimated that the financial costs of livestock losses were about for the year 2013-14 were about Rs 12 lakh from dogs, Rs 10 lakh from snow leopards and Rs 8 lakh from wolves.