Caring for Wildlife: Reducing Feral Animal Insurgence


                                            By Dr. Michael W. Fox 

Caring for all creatures great and small who are still surviving in the diminishing wild by ensuring their well-being is a responsibility all communities and countries must adopt. The harmful incursions of people, free-roaming and feral cats, dogs and pigs, and unattended cattle cannot continue to be ignored.

Domestic animals that adapt to living in the wild are called feral. Feral pigs are becoming an increasing problem in the U.S. and Canada. See Feral Pigs Roam the South. Now Even Northern States Aren’t Safe. The swine have established themselves in Canada and are encroaching on border states like Montana and North Dakota.( Pigs put domestic pigs at risk from diseases such as African swine fever. Native to Eurasia, these animals were first introduced to Canada in the 1980s as exotic livestock for meat. Resulting from farm escapes and intentional releases, wild pigs have already caused widespread problems in Canada’s prairie provinces and many American states.

There is also a feral dog problem. Feral dogs have been documented in all 50 states and estimates of damage in the U.S. from these animals amount to >$620 million annually. In Texas alone, it is estimated that over $5 million in damage to livestock annually can be attributed to feral dogs.(Feral Dogs - Wildlife Damage Management ›)

Feral and owned, free-roaming dogs spread diseases such as distemper and parvovirus that put endangered and protected species like the wolf at risk. According to a recent review, ( Belsare, A., Vanak, A.T. Modelling the challenges of managing free-ranging dog populations. Sci Rep 10, 18874 2020. “The domestic dog (Canis familiaris) is found on every continent that humans have settled1. More than 70% of the global dog population (estimated at > 700 million to ~ 1 billion) comprises of free-ranging dogs (FRD). In many developing countries, FRD are associated with the transmission of zoonotic diseases such as rabies, zoonotic visceral leishmaniasis, canine echinococcosis, and soil borne helminths. Rabies alone is responsible for an estimated 60,000 human deaths per year worldwide, with a majority of these deaths occurring in Asia and Africa. In addition, FRD are an important and emerging threat for livestock as well as biodiversity. Furthermore, FRD also suffer from poor health, high mortality, and abuse. Amongst the countries with the largest FRD populations in the world, India stands out as it accounts for an estimated 20 million dog bite cases per year and around 20,000 dog-mediated human rabies deaths per annum. Apart from being a hotspot of dog-mediated rabies deaths, dog attacks also result in direct human fatalities in India (e.g. There is thus a strong and urgent need to control free-roaming dog populations. In general, efforts to control dog populations in India using a variety of lethal and non-lethal methods have been unsuccessful so far, even though this has been attempted for over 200 years.”

Worldwide, domestic dogs have contributed to 11 vertebrate extinctions and are a known or potential threat to at least 188 threatened species worldwide. (Tim S. Doherty, et al. The global impacts of domestic dogs on threatened vertebrates, Biological Conservation, Part A, 210: 56-59, 2017 They also compete with wild predators and scavengers for food.

Both owned and unvaccinated and feral dogs and cats pose a greater public health risk, as potential carriers of rabies, than wild carnivores such as coyotes and foxes. The feral cat problem is also a major factor in the loss of song birds and small mammals and spread of diseases to wild felids. According to one assessment, “The total across all species of when reptiles, amphibians, and small mammals are included in the tally, scientists estimate that feral cats in the U.S. kill 6.9 to 20.7 billion animals annually. Outside of human-driven habitat destruction, there is arguably no greater threat to small wildlife species—especially birds—than feral cats. Exact estimates ( of this feral cat population) vary, but various sources report that there are between 50 and 70 million feral cats in the United States. Some reports point to figures above 100 million. That’s a lot of cats, considering American pet owners only registered 94.2 million pet cats in 2017. (

In the extensive review by A. Trouwborst et al, Domestic cats and their impacts on biodiversity: A blind spot in the application of nature conservation law. People Nat. 2020; 2: 235– 250. the authors state “Domestic cats have also been implicated at broader scales, in the global extinction of at least 63 species—40 birds, 21 mammals, two reptiles—which is to say 26% of all known contemporary extinctions in these species groups. Likewise, domestic cats currently endanger at least a further 367 species which are at risk of extinction.

These feral animal issues are world-wide and include America’s “wild” mustangs—domestic horses who have become feral out West; cattle and camels in Australia as well as rabbits and cats, where it is estimated that invasive species are beginning to outnumber indigenous ones, many of which they kill or out-compete. In February 2023, 65 cattle, deemed feral, were shot from the air in the Gila Wilderness area in the state of New Mexico according to the Forest Service. The shooters were agents with the Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS). Some APHIS agents specialize in killing predators and nuisance animals. Feral cattle are also an issue in Hawaii and several states including California and Utah

Collectively the negative impact of feral animals on biodiversity must be addressed. The World Economic Forum lists biodiversity loss as one of the top three global risks, because the loss of Nature doesn’t just impact plants and animals. Destruction of forests, wetlands and other natural ecosystems deprives us increasingly of clean air and water, and results in the release of “emergent” diseases, pestilence and pests, which natural biodiversity helps contain. The Biden administration has yet to sign on to support the UN Convention on Biological Diversity 2022 resolution, agreed to by most other countries, to take concerted action to protect at least one third of the world’s natural ecosystems, aquatic and terrestrial.

The issue of invasive species, plant and animals wild and feral, and free-roaming livestock cannot be ignored: nor can the land and natural resource use, along with pesticides and various pharmaceuticals in the intensive production of animal-derived foods (eggs, poultry, meat, fish and dairy) from inhumane and polluting factory farms and feedlots. We must make fundamental changes in how we treat domesticated animals for food, as pets and for other purposes, and those who become feral at home and abroad.


The multiple use concept allowing noisy and polluting all-terrain vehicles, dirt bikes and snow mobiles into wildlife-inhabited areas may be “democratic”. The appeals by hikers, naturalists, wildlife photographers and other lovers of nature undisturbed and undefiled, to prohibit such vehicular traffic are generally ignored by state wildlife “management” authorities.

But an “ecocratic”, non-anthropocentric stewardship of lands belonging to wildlife would be just and enlightened self-interest because our ultimate well-being is dependent upon restoring and protecting natural biodiversity.

Limiting the numbers of visitors to wildlife habitats as well as times and seasons will help reduce wildlife disturbances, disruptions in feeding, breeding, care of young and associated stress increasing susceptibility to disease. Core-areas should be strictly off-limits and at the most, trail-cameras permitted for non-invasive wildlife research and monitoring. Human hikers create a “landscape of fear” that chases other animals into hiding, a new study has found. Even when hikers are unarmed and using the landscape peacefully, they can cause disruption on par with that of apex predators, according to the study published in Scientific Reports.Jan 19, 2023. For details see Anderson, A.K., Waller, J.S. & Thornton, D.H. Partial COVID-19 closure of a national park reveals negative influence of low-impact recreation on wildlife spatiotemporal ecology. Sci Rep 13, 687 (2023).