Coexisting With Wildlife When it Comes to Our Furry Friends-Part 2: Indirect Impacts

For me, pets were a staple part of my childhood. My parents liked animals but it also helped teach us the responsibility of taking care of another living being. I knew my first year living off campus in college I was going to have a pet. As much as I wanted a dog, I knew starting off with a cat would be best (not to mention I like cats a little more than dogs, but truly love them both). Maxwell is my cat, I adopted him from my local shelter and he has been with me for four years now. For the first year, I lived in an above garage apartment as I finished school, and Max remained an indoor cat. After a year of living in that apartment, I moved back home into my parents basement and Maxwell stayed downstairs for the most part. However, I saw his desire to explore more and felt somewhat bad for keeping him from being outside, something that is natural for cats. Flash forward another year and my boyfriend (now husband) and I moved into our first home and had adopted three more cats (another story for another time). Four cats in one house and things felt a little cramped. 

As an environmental science student, I quickly realized the impact that outdoor cats have on bird and small mammal populations, not to mention the impact of domestic animal feces spreading toxins and parasites to local wildlife, but their mere presence alone can impact wildlife behavior and distribution as well. Lucky for me, my husband is handy and we decided to build our cats a catio. Cat patio. Catios truly are the best of both worlds, because they provide your cats outdoor access while protecting them from cars and predators and protecting local wildlife populations from your cats. While the occasional rodent or bird may find their way into the catio and fall victim to your cat, this number is drastically lower than the damage your cat could cause with unrestricted access to the outdoors. 

You know what else is plentiful when you have several animals, I’m just going to say it, POOP. Four cats require a lot of litter and produce a lot of poop. While there isn’t much within my control here, a huge sustainability factor has been refillable litter tubs. I used to have stacks of cat litter jugs, and while they can be repurposed for pet food storage or driveway sand for the winter time, there’s only so many tubs you can repurpose. Our local pet store has a cat litter filling station where you can bring in your empty tub (after an initial purchase of their brand) and refill for a cheaper price. Also, the litter itself is good quality, which is a plus. On the other side of the scoop is what to do with your pet waste. Pet waste is stinky and can even pose a health hazard, so we bag all of the cat waste and throw it into the trash. While this results in the “consumption” of many plastic bags, it keeps harmful waste out of the environment. Using biodegradable bags is an option to reduce your impact, however, I may experiment with not individually bagging waste as our town collects garbage and brings it to a waste to energy facility.

When it comes to dog waste, it should go without saying that picking up dog poop (AT LEAST in public places) is a must. Not only is it respectful to other people using the area, dog waste can make a huge impact on the local ecology. Domestic dogs are one of the most abundant predators in the world, and their simple presence can impact local prey populations by changing their behavior to avoid areas with higher density of domestic dogs¹. Not only does the presence of dogs have impact on prey populations but their presence has also been shown to influence distribution of other mesopredators². At my house, we don’t bag the dogs’ poop, rather we have a designated spot that we toss it into the shrubs along the edge. To bag all of the dog waste and dispose of it via municipal waste would likely be the less sustainable option than letting it decompose. However, because we feed our dogs processed kibble, the influence of their diet in the composition of their waste should be accounted for as well.

Ultimately, the research around domesticated animals, particularly pets, is very limited. However, research shows that humans and their animals account for 97% of mammalian biomass³. While adopting animals keeps them off the streets and out of wildlife habitat, providing for our pets results in higher levels of consumption and waste. As with anything, the goal of sustainability is to avoid, minimize, and mitigate.

What are the take aways?

• Because domestic cats and dogs are predators, their presence typically results in behavioral changes in prey species
• The pet industry is huge and the amount of waste (both materialistic and physical pet waste) is hard to quantify, with limited research into the subject. One major way to reduce plastic waste for cat owners is to find refillable cat littler stations.
• Spaying and neutering our pets helps control populations of domestic animals and reduce the number of strays and those in shelters.

Citations

1. Silva-Rodríguez, E. A., & Sieving, K. E. (2012). Domestic dogs shape the landscape-scale distribution of a threatened forest ungulate. Biological Conservation,150(1), 103-110. doi:10.1016/j.biocon.2012.03.008
2. Vanak, A. T., & Gompper, M. E. (2010). Interference competition at the landscape level: The effect of free-ranging dogs on a native mesocarnivore. Journal of Applied Ecology,47(6), 1225-1232. doi:10.1111/j.1365-2664.2010.01870.x
3. Bar-On, Y. M., Phillips, R., & Milo, R. (2019). The biomass distribution on Earth. Proceedings of the National Academy of Sciences of the United States of America. Retrieved from https://www.pnas.org/content/115/25/6506.