A loyal companion. An emotional creature who has been renowned to be man’s best friend. However, this loyal creature is the root of one of wildlife’s largest problems – rising population of feral dogs.
Feral dogs differ from the normal stray dogs in the sense that the former were born in the wild and have not had any human interaction. Meanwhile the latter, is an individual which has escaped human control. However, the two are not exclusive as stray dogs can easily become feral once it is removed from a human environment such as a city. Globally there are over 90 million free ranging dogs (both stray and feral dogs) which are not in human custody. India is home to 60 million free ranging dogs, out of which 35 million are stray. Dogs are by far India’s most abundant terrestrial carnivore, an ominous sign for local wildlife.
Why does India have so many feral dogs?
Increased Food Availability
There are numerous factors which are responsible for this mass explosion in feral dog populations in the country. As mentioned in an earlier blog, the most significant of these reasons was the vulture crisis of 1990, where 98% of the apex scavenger’s population was wiped out, which led to an over-abundance of untouched carcasses. The surge in food availability and reduction in competition provided an unimaginable advantage for the survival of feral dog population.
Additionally, the problem of open garbage does not help. On a daily basis, 1.8 lakh – or 180,000 – tonnes of exposed garbage find itself in garbage dumps, providing apt feeding grounds for feral dogs. While it has been established that an influx of food supply has been capitalized upon by feral dogs, one must not forget the breeding capacity of these creatures. A bitch can give birth to four to five litters in her lifetime with an average gestation period of 60 days with each litter consisting of four to seven puppies.
Poor Pet Ownership Laws
To make matters even worse, a combination of weak ownership rules of pet dogs coupled with minimal population control measures is further aggravating the problem of feral canine overpopulation. Irresponsible dog owners, who are inept in caring for their pets often abandon these poor creatures on the street, allowing for the stray dog population to grow. Meanwhile, civic bodies, living up to their horrendously corrupt reputation lack the willpower and resources to tackle the issue of gthe growing dog population.
Instead of taking measures to curb the overpopulation of strays, the civil bodies take the easier route out by translocating strays rural areas which are not apart of their constituency. This allows strays to venture out into areas of ecological importance and hence adapt to the lifestyle of a feral. This sheer lack of responsibility by civiv bodies have prodved costly for wildlife. Dogs with theur superior morpholigcal adaptations are able to outperform rival predators in the wild, hence becoming the predator with the highest density in the country. This has very pronounced impacts on local wildlife.
Where and how are feral dogs impacting wildlife?
The extent of the impact of feral dogs on local wildlife was researched by the Zoological Society of London through a pan-India online. The data recorded from participants showed that 80 local species had been predated upon by ferals. Over 50% of these attacks occurred near or withing Portected Areas. To make matters worse, over 70% of the attacks were conducted by packs of ferals whose sizes varied from 3 to 25 individuals. Figure 1 graphically shows the distribution of the reported attacks on wildlife by feral dogs.
Figure 1: Locations of reported attacks on wildlife by feral dogs
As seen from Figure 1, a large number of the attacks were concentrated in areas of high ecological diversity – Western Ghats, especially in Nilgiris, the Deccan Plateau, Gujarat and the higher Himalayas, namely Ladakh and Sikkim. However, one cannot neglect the regions with less frequent feral predatory acts. A potential reason for the relatively a smaller number of reports is largely due to the fact that the areas are lesser developed and lack survey participants. The forests of East Indian states – Jharkhand, Chhattisgarh and the Seven Sisters have a significantly lesser number of visitors and researchers. Data in other aspects of wildlife also lack in these areas.
Overlapping Range of Feral Dog Attacks and Wild Canid Range
Nonetheless, a glaringly common feature of the regions with high numbers of reported feral predation, is the high presence of local canine species. The grasslands of the Deccan Plateau and the arid scrublands of Gujarat are well reputated for its high population of Indian Wolves, Golden Jackal and Bengal Foxes. Striped Hyenas are also found fairly frequently in the region. Meanwhile the Western Ghats have a healthy population of Asiatic Wild Dogs and Indian Wolves.
Meanwhile, the high altitude plains of Ladakh and Sikkhim are home to the Tibetan Wolf, Red Fox and Tibetan Sand Fox. The presence of other canine species vaguely suggests that the above stated regions provide the most suitable habitat for feral dogs in terms of habitat and prey densisty, which in turn explains the excessive frequency of attacks on wildlife in these regions. If local canine species can thrive in these regions, feral dogs will dominate the habitats.
The Ugly Relationship between Feral Dogs and Wild Canids
Very High Disease Transmission Rates
This is a major source of conern as feral dogs are known to spread infectious diseases to not only humans but also local canine species. Ferals are high susecptiable to carry transmissible diseases such as rabies, canine parvovirus (CPV), and canine distemper virus (CDV). As feral dogs have a high tolerance for diseases due to their apt morpholigcal adaptions, these diseases do not have high mortality rates and these creatures become carriers. Being a carrier of such disease is proving fatal. Over 30,000 people die yearly due diseases, mainly rabies, spread by dog bites.
Meanwhile, in the wild, a study in the Great Indian Bustard Sanctuary showed that areas with ferals had 95% more exposure to both CDV and CPV than areas without. This is due to the fact that there are too many methods of transmitting pathogens – scathing and uniration, scavenging on carcasses and usage of water bodies being the most common. Other carnivores, due to increase interaction, are at the largest threat of this spread of pathogens. Unfortunately, no major study has been done on the spread of infectious pathogens by feral canines and the extent to which it impacts local wildlife.
Hybridization
Meanwhile, another issue glooming at large is the hybridization of domestic canines with wild canines. This phenomenon has been observed fairly frequently in West Bengals with Golden Jackals and in Spiti Valley with Himalayan Wolves. Not only does hybridization allow the passing on of pathogens, such as CDV and CPV, to the wild canines, it severely impacts the wild canine genetic pool. When a male feral dog breeds with a female wild canine, the potential of the female to contribute to the canine’s purebred population reduces immensely. Moreover, due to differential parenting behaviour of the two canine species – male dogs are not known to care for the young – the hybridized offspring are less likely to survive,
Feral Dogs Threaten Endangered Birds
Nonetheless, the fact that the above stated regions have such a high frequency of attacks is an immense concern for the wildlife fraternity. Not only, do these areas have a large population of wild canines, these regions have some of the world’s most threatened species. This includes the Great Indian Bustard, Black-necked Crane and both the Tibetan and Indian Wildasses.
Black-necked Cranes are summer migrants to Ladakh and Sikkihm where they breed. Nesting takes place in open marshland areas, hence exposing the eggs to the mercy of feral dogs, for whom the eggs form a delicacy. Even in a failed attempt to sabotage the nests, the dogs are able to frighten the cranes, hence preventing them from returning to protect their nests.
Further enlightening the enormity of the problem, an investigation by wildlife authorities showed that a third of Ladakh’s feral dog population (amounting to about 1,200 individuals) are found within a five kilometre radius of the 13 prime nesting spots for this culturally significant species. The already threatened species seems to be fighting a losing battle against man’s best friend.
The Great Indian Bustard also experiences a similar faith, as they also, nest on the ground. The survival rate of the eggs of this endangered species has been depleted by 60-70%, thanks to the unprecedented increase in predation by ferals. Given that the bustards only lay one egg every couple of years, ferals impose a major hindrance to the recovery of the dwindling population of the bird which was so close from being touted as India’s national bird. To make matters worse, adult bustards themselves fall prey to ferals due to their terrestrial nature. Coupled with the issue of transmission collision rates, the 150 remaining Great Indian Busstards cannot surive the threat of feral dogs.
Ungulates also fall victim to Feral Dogs
As alarmingly as it already seems, these species are not the most affected by this issue. Ungulates are at the receiving end of the feral population. Figure 2 shows the various wildlife predated upon by the feral.
Figure 2: Taxa hunted upon by dogs (Source: Chandrima Home)
As seen from Figure 2, ungulates, both even-toed and odd toed, are the most predated upon by ferals. This is a major concern because, as mentioned earlier, the feral dog predation activity was most commonly seen in the grasslands of Ladakh, and western India. This region is home to some of the most threatened species of ungulates – Blackbuck, Gazelle, and both species of Wildasses. In fact, a study conducted in July 2017, showed that 55 chinakaras were predated upon by ferals. The survival of these ungulates is already in shambles due the destructions of India’s grasslands, and this additional threat could prove fatal.
Feral Dogs are Impact Wild Prey Densities
The feeding patterns of feral dogs is having crippling impacts on not just ungulates, but in fact predators as well. The prey base for the natural predators are being decimated by the feral dogs. Chital deer and sambar deer were the two most hunted species, making up for 41% and 12% of the diet of feral dogs respectively. Sambar deer are the most common prey for tigers due to their salty meat while chital are the most frequently preyed upon by leopards and wild dogs.
The reduction in ungulate population would result in the increased venturing of natural carnivores into human habitation. Livestock would substitute natural prey and human-carnivore conflict would become a more common phenomena. Feral dogs certainly have unleashed their dominance as the most abundant predator on Indian soil. 9
The reduction in prey density most certainly would increase man-animal conflict. This is because predators, such as leopards, would venture into rural areas and feed on livestock. Furthermore, individual stray/feral dogs in rural areas are an easy meal for predators, which also could be a potential temptation for rural venturing of predators.
The Curious Case of Assam
While the impact of feral dogs in the areas where they are most prevalaent has been established, one state is becoming more vulnerable to this threat – Assam. Although, it can be argued from Figure 1 that the reported cases are fairly well spread out relative to other states, protecting the state from this growing local threat is an urgent requirments considering the already significant impact ferals have had on the critically endangered wildlife of the state.
In an interview with Mongabay India, primatetologist Parimal Bhattacharjee, mentioned how the aggressive barking by a pack of dogs in a forest patch near Assam University, Silchar, Assam, forced a troop of Phayre’s leaf monkeys to abandon their natural spot. Such trends were also noticed in Capped and Golden Langur in the state. Furthermore, the critically endangered Bengal Florican is found in relatively high densities in the state, and the increase in dog attacks in the state causes experts to predict a similar faith of the species as their closely related counterparts – the Great Indian Bustard. Another species in the region which cannot be ignored is the Chinese Pangolin, which already is the most illegally traded species in the world.
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