Our Cats and Dogs Have Become a Major Threat to Wildlife — and It’s Getting Worse

As increasing evidence mounts that human activities are driving the extinction of various species across the globe, it would appear that the mass-killing of animals isn’t the fault of us primates alone.

In fact, our favorite house pets – cats and dogs – are playing a huge role in the elimination of wildlife.

This too, of course, is an extension of humans tipping nature’s balance. After all, who else has turned the domestication and sale of predator canines and felines, or the culture of keeping pets, into a major industry?

According to a recent study from Chile, “man’s best friend,” or dogs, have contributed to the extinction of nearly a dozen wild bird and animal species – and nearly 200 more species are facing endangerment from feral and free-ranging dogs.

Responsibility for the threat dogs pose to wildlife often falls on dog owners, who show precious little regard for how their pets behave when loose and roaming the in wild.

Eduardo Silva Rodriguez, one of the authors of the study, told the BBC:

“Predation and harassment by dogs has been documented for the majority of larger terrestrial mammals that inhabit Chile, including the three species of canids (mammals from the dog family) and three species of deer.”

There is an estimated global population of one billion domestic dogs, many of whom are feral and free-range while others are completely dependent on their human masters. According to some conservationists, the figure for loose dogs has been on an inexorable rise, largely in step with the growth of the human population worldwide.

Feral and free-ranging dogs threaten 200 species, 30 of whom are classified as critically endangered, 71 as endangered, and 87 as vulnerable, according to the International Union for Conservation of Nature. Half of these at-risk species are mammals, while 78 are birds, 22 are reptiles, and three are amphibian. Species such as the New Zealand quail are among those who have gone extinct, partly thanks to dogs.

Many of the problematic dogs are those that have been abandoned by humans. Once free, the dogs revert to their nature as predators and kill wild animals, throw ecosystems out of balance, become carries of diseases that are transmitted to wildlife, eat their food, and interbreed with related species such as wolves.

“And that poses a threat to wolves,” Moritz Klose from the World Wildlife Fund (WWF) explained. “If this continues to grow, we will lose the purity of our wolves’ genes.”

Dogs have effectively become the third worst human-introduced invasive predator to disrupt mother nature along with rats, who are estimated to be linked to the extinction of 75 species – and cats, who have been linked to 63 extinctions.

In 2013, cat-lovers were shocked by a study from the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service that found cats were the leading threat to birds in the United States – a finding consistent with similar studies done in Canada and Australia.

And it’s not just that cats kill billions of birds and upwards of 12 billion small mammals per year in the U.S. alone – but cat excrement is also believed to be linked to dangerous parasites and even personality disorders, like schizophrenia, in humans.

The paper pointed out:

“Overwhelming scientific consensus supports that cats are an invasive species; they have caused dozens of extinctions (Doherty et al. 2016), impact native wildlife populations (Loss and Marra 2017), and carry multiple zoonotic diseases (Gerhold and Jessup 2013).”

The American Bird Conservancy (ABC) provoked a wave of what they call “science denialism” from cat-lovers who fear that ABC’s calls for stray cats to be “removed from the landscape” amounts to a cull based on “junk science.”

Grant Sizemore, Director of Invasive Species Programs for ABC, said:

“What is overwhelmingly evident based on the science is that maintaining cats on the landscape is harmful for cats, wildlife, and people … It’s time to treat cats like dogs and to safely remove stray and feral animals from our parks and neighborhoods.”

The scientific community has long argued that “misplaced compassion” could be the enemy of reason, and that by favoring our beloved “best friends” we could be condemning much of the animal kingdom to premature death. In such a context, the mass eradication of stray cats and dogs – along with strict controls on how we deal with our outdoor pets – may be wholly necessary.

So yes, sadly, humans are at a crossroads: do we continue tipping the scales against the rest of mother nature in pursuit of our own narrow interests as dog- and cat-lovers, or are we willing to make the tough choices that prove essential to avoiding the annihilation of what little left remains of Earth’s biological diversity?