Image Credit: Scientific Frontline
Scientific Frontline: Extended "At a Glance" Summary: Ecological Role of Urban Hyenas
The Core Concept: Spotted hyenas and other native scavengers in Mekelle, Ethiopia, function as essential components of the urban ecosystem by consuming thousands of tons of discarded organic meat waste. This natural scavenging acts as a vital ecosystem service, positioning these predators as accidental "eco-warriors" within high-density human settlements.
Key Distinction/Mechanism: Unlike traditional conservation models that assume large carnivores require vast, human-free natural environments to thrive, this phenomenon demonstrates a mutually beneficial coexistence in an urban setting. The scavengers actively clear organic waste from roadsides and open spaces before it can decompose, thereby preventing the release of greenhouse gases and eliminating breeding grounds for disease.
Origin/History: The findings stem from a recent study led by Dr. Gidey Yirga at the University of Sheffield's School of Biosciences. Researchers surveyed over 400 households to quantify urban waste generation, discovering that approximately 1,058,200 animals are slaughtered domestically each year in Mekelle, resulting in massive quantities of roadside meat waste.
Major Frameworks/Components:
- Emission Mitigation: By consuming decomposing organic matter, urban scavengers prevent the release of over 1,000 metric tons of carbon emissions into the atmosphere annually.
- Economic Valuation: The natural waste disposal provided by these animals saves the city an estimated $100,000 USD per year in municipal waste management costs.
- Sanitation Management: The rapid removal of approximately 1,240 metric tons of meat waste drastically mitigates catastrophic sanitation risks and disease proliferation associated with routine roadside dumping.
- Human-Wildlife Coexistence: The study found high rates of local recognition and appreciation for the scavengers, underscoring the social viability of integrated urban ecosystems.
Branch of Science: Urban Ecology, Conservation Biology, Environmental Science, and Zoology.
Future Application: This ecological model offers a scalable blueprint for urban waste management and conservation strategies across other Ethiopian cities and African nations facing similar sanitation and infrastructure challenges. Additionally, the research establishes a baseline for future studies investigating how urban lifestyles and diets physically or genetically alter these scavengers compared to their wild counterparts.
Why It Matters: At a time when municipalities globally struggle with waste management and climate targets, this study highlights an unexpected, naturally occurring climate mitigation strategy. It proves that fostering a peaceful coexistence with adapted urban wildlife can yield profound economic, environmental, and public health benefits.
Urban scavengers like spotted hyenas are preventing over a thousand tons of carbon emissions annually in Ethiopia’s second-largest city, according to new research revealing the predators’ role as accidental eco-warriors.
Urban scavengers like spotted hyenas prevent over a thousand tons of carbon emissions in Ethiopia’s second largest city, Mekelle, each year by consuming meat waste left to rot at roadsides
These accidental eco-warriors save the city more than $100,000 USD annually in waste management costs and mitigate potentially catastrophic sanitation risks by clearing animal carcasses from roadsides and open spaces
The study, led by researchers from the University of Sheffield, highlights a mutually beneficial coexistence between large carnivores and people in urban settings, offering a model that could be adapted across Ethiopia and other African states where waste management is a challenge
Urban scavengers like spotted hyenas are preventing over a thousand tons of carbon emissions annually in Ethiopia’s second-largest city, according to new research revealing the predators’ role as accidental eco-warriors.
By consuming organic waste that would otherwise rot, these predators are saving the city of Mekelle over $100,000 USD in waste management costs while reducing the significant sanitation risk associated with routine roadside dumping.
In Mekelle, a rapidly urbanizing city with a population of over 660,000, over one million chickens, goats and sheep are slaughtered in people’s homes for food each year. The leftover parts of the animals not consumed by people are then discarded, with two thirds of the organic waste being dumped at roadsides or other open sites.
The University of Sheffield-led study reveals urban scavengers such as spotted hyenas, African wolves and vultures are providing a vital ecosystem service by consuming waste that, left to rot, releases greenhouse gases and spreads disease.
Research lead Dr Gidey Yirga, from the University of Sheffield’s School of Biosciences, said: “At a time when cities across the world are struggling with waste and climate goals, we’ve found that scavengers are providing essential ecosystem services while significantly reducing potentially catastrophic sanitation risks.
“Animals like spotted hyenas have adapted to a high-density, urban environment and have become an essential part of the city’s ecosystem.
“This demonstrates a mutually beneficial coexistence between people and large carnivores that, in most circumstances, require vast natural environments free of human intervention.”
To understand the scale of organic waste discarded across the city, researchers interviewed over 400 randomly selected households to understand their waste disposal habits. This data was extrapolated across the entire city, revealing that approximately 1,058,200 animals are slaughtered each year in people’s homes.
This generates 1,240.6 metric tons of meat waste - the equivalent to the total weight of roughly 31,000 live sheep. In a city with generally poor waste management and sanitation, this mountain of meat waste is dumped along roadsides and other open sites throughout the city.
The study found that by scavenging meat waste, urban predators are preventing over 1,000 metric tons of carbon emissions entering the atmosphere and saving waste disposal services worth over $100,000 USD annually.
Dr Yirga added: “In our conversations with residents we found that they recognize and appreciate the benefits of living alongside these urban scavengers, highlighting the further potential of a peaceful coexistence between wildlife and humans in urban areas.
“This model could be applied to other Ethiopian cities and across many other African states where organic waste is routinely dumped at roadsides.”
Having established hyenas and other scavengers' value to the city, the research team is now turning its attention to the animals themselves. The next phase of the research will investigate how their urban lifestyle could be physically changing the animals by comparing them to their wild counterparts.
Published in journal: Ecological Solutions and Evidence
Authors: Gidey Yirga, Robert P. Freckleton, Hans Bauer, and Andrew P. Beckerman
Source/Credit: University of Sheffield
Reference Number: eco031026_01
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