Cats, Dogs, and Wildlife

By David Cronenwett

A recent study detailing the effects of domestic cat predation on wildlife has caused an uproar among the animal welfare and conservation communities. Researchers from the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service (USFWS), in a report entitled The Impacts of Domestic Cats on Wildlife of the United States, determined that the little felids kill a median of 2.4 billion birds and 12.3 billion mammals per year, most of them native species. This paper represents the most thorough attempt to date at quantifying such predation. It’s results astonished everyone since they are about three times higher than previously assumed mortality figures. Our cats are tremendously efficient predators, and now we have a better picture of just how much so.

This research elevates house cats to the single greatest, direct anthropogenic impact to smaller-bodied wildlife; more than roadkill, collisions with windows, poisonings, you name it. It is a damning indictment and responses both supporting and refuting the paper’s findings were swift and emotionally charged. Conservation organizations such as the American Bird Conservancy felt the research bolstered their position that all cats should be kept indoors at all times. On the other side, some animal welfare advocates feel that the study will create a public “backlash” against feral cats, which are hugely abundant in some urban areas. Whether domestic cat predation is causing significant impacts to threatened or endangered bird populations on a large scale is doubtful, but this does occur in specific instances. Florida Keys National Wildlife Refuge Complex recently authorized the trapping of feral cats to protect native wildlife. The USFWS justifies its actions by recognizing cats as an exotic species, controllable under its Pest Management Plan.

For many years, birders have understood the negative impact of cats on the feathered. But lest dog owners begin to feel smug, the hounds are not off the hook either. A growing body of literature is beginning to illuminate the many unseen ecological effects of dogs. Wildlife advocates should be especially concerned with this issue because while cats tend to stick closer to human settlement, dogs are frequently brought into wildland-urban interface zones and backcountry areas as companion animals. Research in Colorado, Montana and Utah has demonstrated significant wildlife displacement due to pervasive scent marking by dogs as well as outright wildlife harassment. Different seasons in the northern Rockies present different problems; Fido in ungulate winter range can severely stress deer, elk and moose when they (unlike your dog) have no calories to spare. In spring and early summer, newborn creatures from ground nesting birds to elk calves are little more than playthings for an enthusiastic dog. Also, there are known instances of domestic dogs transmitting diseases to and from wildlife and dogs are now considered to be effective vectors for the spread of noxious weeds.

It is no surprise that some people become defensive about this issue, since relationships with our pets are often as profound as with others of our own kind. The growing problem of “pets vs. wildlife” essentially comes down to the ancient practice of domestication, that is, the human penchant for shaping the behavior of other living things to benefit ourselves. The case of cats and dogs is interesting because it represents instances where both species demonstrate a degree of willing “self-domestication” by initially approaching and tolerating humans. The resulting relationships proved to be very long lasting and beneficial for all involved.

Our cultural bond with dogs and cats is complex and deeply rooted. Archeology puts the earliest known domestication of canids at over 33,000 years, but our association with them is likely older. Though difficult to believe, all modern breeds, from the sled-hauling malamute to the foot-warming Cavalier, are directly descended from wolves. Dogs aided Pleistocene humans in hunting, were used for protection, as beasts of burden and quickly became close companions. Some native peoples in Alaska consider dogs to be something of a bridge between the wild and domestic worlds which is fitting since they are likely the first organism intentionally used and shaped to serve humankind. A new theory suggests that dogs gave Homo sapiens a devastating hunting advantage over Neanderthal culture and significantly contributed to our ultimate survival as a species. In 2011, ritual burial sites of domestic dogs with mammoth bones deliberately placed in their mouths, were found at Predmosti in the Czech Republic, dated 27,000 years before present. Clearly, the relationship was a spiritually meaningful one.

Cats do not show a pronounced association with people until the arrival of agriculture. The practice of storing large quantities of grain inevitably brings with it the problem of rodents. Wild cats were probably attracted to granaries by the predictable abundance of vermin and early farmers quickly realized how beneficial this relationship could be. Cats were later culturally venerated by empires in Egypt and Persia. It isn’t a stretch to imply that domestic cats had a significant role to play in the establishment of agriculture and eventually the civilizations it enabled.

In the present however, we are beginning to understand how our pets can adversely affect native habitats and wildlife. Because of long entangled histories and the personal relationships we develop with cats and dogs, there is a tendency to sometimes deny or ignore their ecological impacts. Better pet management will certainly result in more abundant wildlife. Some communities in the US already have ordinances restricting cats entirely indoors or leashed outdoors. It may also be time to examine if some especially sensitive habitats should be designated as domestic dog-exclusion areas. Though a challenging issue to address, more responsible pet ownership would go a long way towards furthering the conservation of native wildlife.