When we think of wolves, vultures, bats or goannas, we might picture danger, disease, or inconvenience. But science is telling us a different story — one that positions these often-feared species as unsung heroes in the fight for a healthier planet.
Our recent paper published in BioScience argues that predators and scavengers play vital, underappreciated roles in maintaining ecological balance and even safeguarding human well-being. Far from being threats, these species are ecosystem regulators, quietly delivering public health benefits and economic value.
From Pest Control to Public Health
Take bats, for example. After bat populations in North America were decimated by white-nose syndrome, farmers had to compensate for lost insect control by using more pesticides. The result? A spike in agricultural costs — and alarmingly, a possible 8% increase in infant mortality in affected regions. The link? More insecticides, more environmental exposure, more risk.
And the vultures of India? Their rapid decline in the 1990s (due to a veterinary drug called diclofenac) caused livestock carcasses to pile up, triggering sanitation crises. Researchers estimate this led to over half a million human deaths and a $69 billion economic impact.
Biodiversity That Pays Off
It’s not just about disease. Predators like the New Zealand falcon help protect vineyards from grape-eating birds. Wolves reduce wildlife–vehicle collisions, saving human lives and insurance costs. Even reptiles like the Australian heath goanna help farmers by consuming fly-attracting carcasses that would otherwise impact livestock.
In short: these animals provide services — pest control, waste removal, disease regulation — that we’d otherwise have to pay for. And often, we’re not even aware of their silent labor.
A Call for Smarter Conservation
Yet despite these benefits, predators and scavengers are in steep decline — hunted, poisoned, or crowded out by development. Their role in planetary health is rarely recognized in global biodiversity frameworks. We urge policymakers to formally include these species as indicators in sustainability metrics, aligning with goals like the UN’s Kunming-Montreal Biodiversity Framework.
Of course, coexistence isn’t simple. A lion that controls herbivore populations may also prey on livestock. That’s why the paper calls for a net-benefit approach: weigh the costs and contributions together, rather than making decisions based on fear or folklore.
The Takeaway
Planetary health isn’t just about climate graphs and pollution stats. It’s about recognizing the web of life that supports us — including the toothy, winged, or misunderstood creatures that clean, balance, and heal our ecosystems.
Protecting predators and scavengers isn’t charity. It’s public health insurance, food security, and climate resilience rolled into one — nature’s services, offered daily, free of charge.
Want to dig deeper? The full article is open access via BioScience.
Christopher J O’Bryan, Alexander R Braczkowski, Pim Martens (2025). Predators and scavengers as sentinels for planetary health, BioScience, https://doi.org/10.1093/biosci/biaf054
PIM MARTENS 