Is your pet dog leaving a bigger carbon pawprint than you know?

From predators to polluters: A study by researchers at Curtin University, Australia argues that pet dogs might be a greater threat to the wildlife and environment, and they're getting a free pass

They say a dog is man’s best friend. With over a billion pet dogs worldwide, it’s easy to see why. They have become an inseparable part of life for millions of people across the globe as pets and companions. Yet, as their numbers continue to rise, an unsettling question has begun to surface: could they be harming the environment?

 

A recent study by Bill Bateman and Lauren Gilson of Curtin University, Australia says pet dogs might be a greater threat to the wildlife and environment. How? Through their natural predatory instincts, an unsustainable food industry, and the sheer volume of waste they leave behind, argues the study titled ‘Bad Dog? The Environmental Effects of Owned Dogs’.

 

 

Predatory behaviour of pet dogs

“Dogs are predators – the only large carnivore that has been domesticated. Even as pets, they retain their predatory behaviour...,” the study highlights.

 

The study states the most predatory behaviour retained by dogs is that they chase and attack. Despite the fact that pet or owned dogs often have limited chances to interact with wildlife, they still manage to do so — especially when taken into natural spaces by their owners.

 

However, dog attacks can happen surprisingly close to home as well. One study from a wildlife rehabilitation centre in Queensland, Australia, found that 9.2 per cent of animal admissions were due to dog attacks, mostly involving mammals and reptiles. Moreover, these cases had the highest mortality rate, with nearly 73 per cent of affected animals not surviving.

 

The researchers further went on to claim that off the leash pet dogs have been a major factor in the near-collapse of Little Penguin colonies in Tasmania. “Between 1980 and 2020, 55 mortality events at colonies were due to dog attacks, which represents 91 per cent (887 deaths) of all penguins reported dead,” the report mentioned.

 

Another example cited by the study was of shore-nesting birds. It claims that in Western Australia, off-leash dogs were believed to be responsible for killing chicks of the endangered Fairy Tern, and also for numerous disturbances of breeding birds by running through beach colonies.

 

Associated pollution problem

A particular problem arises when dogs enter lakes or rivers. Pet flea and tick medications, especially those containing fipronil or imidacloprid, are highly toxic to aquatic insects. When dogs enter any of these water sources, these chemicals wash off into water bodies, quietly killing off key invertebrate species.

 

“Up to 86 per cent of fipronil, an anti-flea and tick insecticide applied to dogs, rinses off when the dog is washed, or enters water, and is toxic to aquatic invertebrates at low concentration,” the study argues.

 

It further adds that even when dogs are not present in an area, they can still have an effect with their glandular scent marks, faeces, urine, and other traces that effectively indicate ‘presence of predators’ to multiple wildlife taxa.

Dogs excrete over 1,000 kilograms of feces and 2,000 litres of urine in their lifetime. This waste, especially when left uncollected (which is common), can pollute urban waterways and alter soil chemistry. Even worse, it spreads diseases—zoonoses—that jump from pets to wildlife, and potentially humans.

 

The dog food dilemma

Pet food—often rich in meat—contributes significantly to greenhouse gas emissions, land and water use, the study states. Globally, the dog food industry consumes resources equivalent to nearly twice the land area of the United Kingdom. Moreover, up to 13.5 per cent of the global catch of small fish isn’t consumed by humans, but ends up as pet food.

 

What’s the fix?

Researchers believe that the solution to this problem is only going to begin with awareness. Better enforcement of leash laws, educating dog owners about sensitive habitats, and pushing for sustainable dog food options can make a difference. But this won’t be easy. Various reports suggest that many dog owners ignore rules, even when aware of the consequences, often seeing protected beaches and parks as their right to access.

 

Pet ownership is also witnessing a sharp rise in metro cities of India with dogs dominating the market. The population of pet dogs in India was around 33 million in 2023, and is estimated to be over 51 million by 2028, reported India Today. Countries from across the globe will have to formulate policies to manage this crisis.

“There needs to be a dialogue on how we can maintain our important relationship with companion animals and balance that with a meaningful, sustainable stewardship of the environments on which both people and their dogs and resident or migratory wildlife depend,” the study concludes.

Dogs are likely to continue to be an integral part of our lives. The question is — are we ready to clean up the mess?