Scavengers Are Disappearing and That’s Making Us Sick

The animals that once quietly kept nature clean and disease-free are vanishing, and their absence is putting human health at risk. A new study from Stanford University has revealed that more than a third of vertebrate scavengers—animals that feed on carrion—are now threatened or in decline. The worst-hit are the larger, apex scavengers like black-backed jackals and vultures, which play a critical role in disease control.

According to lead researcher Rodolfo Dirzo, these “specialized” scavengers are being replaced by smaller species like rats and feral dogs, which not only fail to clean up as effectively but are themselves carriers of zoonotic diseases. That’s bad news for humans. In India, for example, the 1990s collapse of vulture populations led to a rise in feral dogs, an explosion in dog bites, and tens of thousands of rabies deaths.

The loss of apex scavengers throws entire ecosystems out of balance. Much like how removing wolves from Yellowstone led to overgrazing and biodiversity loss, removing scavengers opens the door to disease outbreaks and waste accumulation. In Ethiopia, spotted hyenas remove hundreds of tons of livestock waste annually, preventing anthrax and tuberculosis spillovers.