Dog trouble: Is our best friend a foe for wildlife?

Our best friend could mean a matter of life and death to wildlife. A pan-India survey has sniffed out data on domestic dogs attacking as many as 80 species, including those dwindling in numbers such as the golden langur, the great Indian bustard and green turtles. Nearly half of these attacks have taken place in or around protected areas.

In a bid to understand the impact of free-ranging dogs on native wildlife in India, which many experts claim is an “under-reported” fact, Chandrima Home of the Ashoka Trust for Research in Ecology and the Environment or ATREE and colleagues zoomed in on dog-wildlife interactions in India through an online survey and by scrutinising reports from national print media.

“We found it is largely a problem across India, despite the limitations of an online survey,”Home told Mongabay-India. “Dogs were reported to attack nearly 80 species of wildlife and most of the attacks were on mammals – largely ungulates, like cattle, and small carnivores. In some places, respondents reported multiple attacks. Majority of these attacks were by free-ranging dogs unaccompanied by humans and in packs. Nearly half of the attacks led to the death of the animal.”

Wildlife going to the dogs

Out of the 80 species documented, 31 were ‘threatened’ as per the IUCN Red List, including four critically endangered species. Vultures, great Indian bustard, Bengal florican, Chinese pangolin, green turtles, Himalayan goral, Asiatic wild ass, red panda and the golden langur are among the species on the edge of survival, which were reportedly attacked between 2000 and 2016.

Data from the study shows that of the 249 responses, 73% reported sightings of domestic dog attacks on wildlife. Nearly 78% of the respondents from the online survey perceived the presence of dogs in and around wilderness areas to be harmful to wildlife.

Globally, cats, dogs and even rodents and pigs are known to disrupt wildlife, endangering about 600 species that are classed as vulnerable to critically endangered in the IUCN Red List. Studies show dogs have contributed to 11 vertebrate extinctions and imperiled 188 threatened species worldwide.

Out of an estimated one billion domestic dogs globally, India is home to about 60 million, the fourth highest in the world.

High dog density in India is attributed to poor dog ownership rules and lack of sustained efforts in population control and due to increased availability of food waste. Home believes a combination of all these factors influences the negative impact of dogs on wildlife.

“Since domestic dogs occur at densities higher than natural predators, the frequency of attacks on prey species is also likely to be high, especially in and around protected areas which are generally small in size in India. Large mammals find it difficult to fight back when dogs charge in packs,” she said.

Home said in India, much of the free-ranging dogs are loosely associated with humans and even if they are pets, they are generally off the leash and therefore have a propensity to interact with wildlife in several cases, due to their proximity to buffer zones and protected areas.

Dogs can venture out in these areas even if they may be fed at homes. It is important to recognise the fact that a large proportion of these attacks occur without being accompanied by humans, indicating whether they are owned or not, their free-ranging nature can have significant impacts on wildlife, she stressed.

“The effects of these attacks on populations that are actually in decline could be disastrous. It’s almost like the final nail in the coffin. When a species such as the great Indian bustard has shown already serious decline due to numerous reasons, predation by domestic dogs can push the species to extinction,” Home said.

The researchers cautioned against an “observation bias” in the data accumulated since larger sized species tend to get reported more.

Dogs exacerbate edge effects

The assessment also spotlights the role of dogs in driving changes at the boundaries of habitats (edge effects). These edge effects, which are basically ecological effects that stem from the creation of habitat edges, either naturally or by human activities, have important implications for forest fragmentation and conservation.

About 48% of the attacks were also reported within protected areas and buffer areas around them, pointing to, as Home said, a “pervasive threat” to biodiversity. This data also suggests “dogs are an important part of the edge effect around protected areas in India.”

“When habitats are fragmented, there are several edge impacts,” Home elaboraed. “For example when a road passes through a protected area, there are impacts on the species that are at the boundaries. Similarly the movement of dogs within such areas and longer forays can extend the impact of the edge.”

As an example, primatologist Parimal Bhattacharjee cited a recorded aggression in a small forest fragment near Assam University campus located in Silchar, Assam, in which a troop of six endangered Phayre’s leaf monkeys (prominent for their ‘spectacles’) were forced to abandon their regular areas following intense barking by domestic dogs.

“Coupled with the fact that there is large scale destruction of habitat for the procurement of agricultural land and setting up new human settlements, high dependency of locals on fuel wood, the aggression between the Phayre’s leaf monkeys and dogs may result in expulsion of the monkeys from their native area,” Bhattacharjee, who was not associated with the study, told Mongabay-India.

Similarly, there are reports of golden langurs forced to clamber down from trees to cross roads and move across to the other side of the forest due to habitat fragmentation, and coming under attack from domestic dogs.

“These [golden langurs] are non-urban species and when they enter villages at the edge of forests, they are subjected to aggression by dogs owned by villagers to protect livestock from predators. In certain areas, canopy construction was carried out to protect them-from a combination of road kills and dog attacks,” Bhattacharjee said.

Conservation biologist Sanjay Gubbi said domestic dogs have both direct and indirect impacts on wildlife, competing for prey with wild carnivores.

“They hunt wild animals from smaller wildlife such as hare, monitor lizards to large mammals such as chital and sambar,” Gubbi of Nature Conservation Foundation, who was not associated with the study, told Mongabay-India. “We see this regularly in our camera traps where domestic dogs are carrying or chasing wild prey. Hence they compete for prey with wild carnivores. Lowered wild prey density affects species such as leopards and can cause leopards to shift to domestic prey leading to increased human-wildlife conflict.”

The experts also underscored domestic dogs as reservoirs of diseases that are transmitted to dhole, wolf, jackal, fox and other canids and felids.

Whose dog is it anyway?

Approximately 87% of the respondents felt the need to control dog populations around wilderness areas, an observation that underscores the need to rethink population management and address the threat of dogs as a conservation problem for wildlife, feel experts.

“When it comes to dog population management nobody actually wants to look at one of the most important problem in India, ie dog ownership policies,” Home said. “People like to feed dogs (easy way to show compassion) but do not want to be responsible pet owners. Also sterilisation is considered the only way to curb population.”

Though trap-neuter-release (16%) followed by euthanasia (14%) were chosen as methods for dog population control by respondents in the survey, a majority (61%) opted for multiple methods of population control such as the ones above in combinations with reducing food availability and translocation to dog shelters.

“Restricting free-ranging behaviour is very important and that can only come with strong laws,” Home said. “In certain cases, hard decisions also have to be taken but in a humane way. One cannot have dogs around sensitive conservation areas. Disowned and feral ones should be removed. Animal welfare should not just be about dogs but also the gamut of wildlife being affected by the dogs themselves.”

However, behavioural biologist Anindita Bhadra flagged a concern regarding perception of dogs not being a part of the local biological diversity. “This is a very western view of dogs – dogs being considered only as pets. This is a very myopic view. Would researchers say the same about dholes or dingoes?” Bhadra from IISER-Kolkata questioned.

According to Andrew Rowan, chief scientific officer for The Humane Society of the US and former president and CEO of Humane Society International, the issue of stray dogs worrying/killing wildlife in India is very similar to the complaints in the US by conservation biologists that cats are responsible for a huge amount of bird mortality.

“The core problem is the encroachment of human communities into protected areas and the humans are then accompanied by dogs who may, or may not, remain close to their human commensals as they explore their environment,” Rowan added.

This article first appeared on Mongabay.