Find could offer lessons for conserving key species in other places
Vultures have long been associated with death, and perhaps for good reason. With their hunched shoulders, hooked beaks, and signature bald heads, they fly around looking for dead and decaying animals to scavenge. But they also serve an important role in protecting human life, a new study finds.
The near-extinction of the birds across India in the 1990s led to the spread of disease-carrying pathogens from an excess of dead animals, killing more than a half-million people from 2000 to 2005.
Vultures are a keystone species in India, essential to the functioning of many of the country’s ecosystems. The birds of prey don’t just clean up disease-ridden carcasses; by removing food, they reduce the populations of other scavengers, such as feral dogs that can transmit rabies. What’s more, without vultures, farmers dispose their dead livestock in waterways, further spreading disease.
And that’s exactly what happened. In 1994, farmers began giving a drug called diclofenac to cattle and other livestock for pain, inflammation, and other conditions. But it was poisonous to the vultures that fed on these animals, destroying their kidneys. In just a decade, Indian vulture populations fell dramatically, from 50 million individuals to just a couple thousand.
Anant Sudarshan saw the impacts firsthand. As an adolescent in India, Sudarshan—now an environmental economist at the University of Warwick—says the bodies of cattle accumulated outside tanneries and city limits, where fields became carcass dumps for feral dogs and other less efficient scavengers such as rats to feed on. When the remains piled up, the Indian government required tanneries to use chemicals to dispose of the waste, causing toxic substances to leech into waterways used by people.