Pets as Indicator Species for the Domestic Environment

Certain species of plants and animals are characteristic of various natural and man-made communities.  Biological indicator species can provide valuable diagnostic information on the state of biological conditions in the community they live in.  Disturbances to the community from natural or man-made events will affect the health, behavior and distribution of its indicator species.  Indicator species can therefore act provide an early warning of degradation in an ecosystem and as measures of general environmental quality.

 

Many researchers are currently conducting studies to assess which species of animals or plants best act as sentinels for different types of contaminants in specific kinds of environments. This week the Santa Rosa Press Democrat published an interesting article titled Green Living With Pets in Mind.  The author noted that the indoor environment of our modern homes may be a less healthy place for our pets to live than we believe it is and wondered if they may be acting, in effect, as indicator species for the modern human domestic environment.

Scientists often cite our companion animals as “canaries in the coal mine.” Household environmental toxins can be a major concern. According to a report from Environmental Working Group (EWG), industrial chemicals show up in our pets at even higher rates than the average human, The chemicals most detected were stain and grease proof coatings and flame retardants used in furniture and flooring.

“At the forefront of people’s minds is if a home is pet friendly, then more importantly it will be human friendly,” says Andy Bannister of Earthtone Construction in Sebastopol. He says it makes sense that if animals are more susceptible to the toxins often contained in building materials, making it safe for them will make it safe for the human occupants.

Our house pets live their lives in much more intimate contact with the chemically treated and – or contaminated surfaces in our home than we do.  Not only are they in regular contact with floors, lawns, furniture and indoor air – they regularly lick and groom their feet and fur and often eat things off the ground or floor.  In many modern homes, housepets often also spend a lot more time in the house and/or yard than their owners do.  This more constant and intimate contact with potential toxins in our homes and yards may mean that our pets will be adversely affected by them before we are.

In fact, the University of Montana Center for Environmental Health Services recently published reports on the potential for using domestic cats as indicator species for indoor air quality and dogs for conditions that may dispose them (and us) to bone cancer.  

There are many advantages to using a sentinel species as indicators of human health hazards. Animals share the human environment, and are therefore exposed to many of the same dangers as humans. They often consume the same foods or water as humans and breathe the same air. Animal species and humans often react to many toxic agents in similar ways, and regularly respond to the toxins by developing comparable diseases.

However, animals usually develop environmentally induced pathological conditions more rapidly than humans. Because animals generally have a shorter lifespan than humans, their diseases progress more rapidly and their susceptibility to toxic chemicals can increase more readily. Sentinel animals can provide an early warning of potential risks to humans before the human population is actually effected. All of these factors show the potential value of sentinel species; they can provide early warning of situations which may require further study, and can also suggest potential causes and effects.

Virtually every type of cancer seen in humans also occurs in pets — and the incidence of cancer we see in our pets is on the rise.  We don’t yet know the reason for this disturbing trend though I suspect there are several factors involved.

First is the greatly improved diagnostic abilities in veterinary medicine. Cases would have gone undiagnosed a few years ago can now be diagnosed with equipment and tests that weren’t previously available.  Another related factor is the increasing sophistication of pet owners regarding health problems.  Pet owners may be better educated today about the importance of early diagnosis and treatment and may be apt to notice more subtle physical and behavioral changes than we did in the past.

Unfortunately, it’s also likely that environmental factors have also led to the observed increase in cancer diagnoses in our pets. Since we are afflicted with the same types of cancers and other environmental diseases that our pets are — it may be reasonable to assume that they are a valuable indicator species for our domestic environments and to use more caution in the products we bring into contact with their lives — and ours.