Sumaya AddishScavenger animals have a bad reputation. For example, My sister says I laugh like a hyena, and I often compare people I dislike to vultures – our figurative language is the nail in a scavenger’s coffin as we associate them with being obnoxious, heartless, and evil. However, this misplaced animosity blocks us from seeing these animals beyond their appetite and understanding them as an integral part of our ecosystem.
What is a scavenger?
A scavenger is an animal that consumes organisms that have died due to causes such as predation, injury, or disease. There are two types of scavenger animals – obligate and facultative. Obligate scavengers primarily survive on scavenging. Amongst them are vultures, yellowjackets, and termites, with vultures being the only vertebrate obligate scavengers. Conversely, facultative scavengers include more diverse species that capitalize on scavenging but also engage in hunting. Most carnivores, like lions, tigers, and bears, fall into this category. While feasting on carrion (dead and decaying flesh) is looked down upon, removing decomposing matter from the ecosystem is important to keep it clean and free of pollutants and disease. Scavengers are nature’s cleaning crew.
How are scavengers good for the environment?
Greenhouse gases (GHG) trap heat in the atmosphere and contribute to climate change. Decomposing matter releases GHGs such as nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4). In large and sustained amounts, GHGs are highly detrimental to the health and safety of humans, animals, and the environment. All scavenger animals provide an essential ecosystem service by rapidly and efficiently removing decomposing matter from the environment. This helps mitigate GHG emissions and other harmful effects of long-term exposure. In the absence of scavengers, particularly obligate vultures, decomposing matter remains in the environment longer. In the case of decomposing carcasses, unless humans interfere by either burning or burying it, the carcass will attract facultative scavengers and simultaneously succumb to slower decomposition mechanisms.
A 2019 study reported turkey vultures were responsible for removing 1,000 tons of organic waste a year. This study and many similar examples underscore the importance of scavengers in maintaining the delicate ecosystem balance. However, scavenger populations are threatened worldwide. With 73% of the world’s vultures critically endangered, facultative scavenger populations are on the rise – destabilizing trophic cascades, or food chains. Facultative scavengers lack the pathogen-destroying digestive tract of vultures, meaning they have a high risk of getting sick from carrion. This effect is most harmful in urban landscapes where human-wildlife contact and conflict are higher – increasing the risk of disease transmission between humans and animals (domestic and wild). Habitat loss due to urbanization, climate change, and other forms of human perturbation dramatically change how animals interact with each other, humans, and their environment.
While I may have convinced you that scavengers are beneficial in reducing greenhouse gases, the lingering negative attitude about them may persist. Animals do not have to be cute and cuddly for us to care about them. Although they dig through our trash and pick at road kill, they are an important part of ecology. There are many steps we can take to protect and respect our local scavengers. We can avoid leaving trash out that may attract them and avoid toxic pesticide use as much as possible. These actions may seem small, but they have the potential to profoundly affect the health and safety of native wildlife and fauna. Now, more than ever, forging a just and reciprocal relationship with the Earth is an important task for all – you can start by looking up at the sky and thanking the vultures that scan overhead.
Peer Editor: Molly Parrish