Vulture collapse fuels the stray dog, disease and wildlife crises

The disappearance of vultures triggered a chain reaction now threatening public health, biodiversity, and conservation policy across India.

- SUNIL GADHOKE

India’s ecological and public health systems continue to grapple with the long-term consequences of the collapse of vulture populations—a crisis that began in the early 1990s and has since cascaded into a nationwide stray dog and disease emergency.

Vultures, once numbering nearly 40 million across India, declined precipitously within just a few years. The cause was traced to diclofenac, an anti-inflammatory drug intended for human use. After the drug’s patent expired, inexpensive generic versions became widely available and were increasingly used in veterinary medicine. When livestock treated with diclofenac died, vultures feeding on contaminated carcasses were poisoned, leading to mass mortality and pushing the species to the brink of extinction.

Vultures are a keystone species, essential for maintaining ecological health. A single flock can strip a 400-kilogram buffalo carcass to the bone in under an hour, preventing the spread of pathogens. In a country with more than 500 million livestock, according to the 2019 census, vultures historically played an indispensable role in carcass disposal. Farmers traditionally left dead animals for vultures to clear. Their sudden disappearance triggered severe ecological repercussions.

Studies have shown that the collapse in vulture populations during the 1990s indirectly caused hundreds of thousands of additional human deaths. With carcasses left unattended, stray dog populations expanded rapidly. Unlike vultures, dogs multiply quickly and act as vectors for disease. In 2023, the Government of India acknowledged in Parliament that the country records approximately 3 million dog bites annually, along with an estimated 18,000-20,000 human deaths from rabies each year, citing World Health Organization data.