1993: In 1993 there were around 40 million vultures in India. By 2007, the population of the long-billed vulture had plummeted by nearly 97 per cent, while the oriental white-backed vulture had fared even worse, with numbers down by more than 99 per cent.
Scientists eventually linked these disastrous declines to the veterinary use of the drug diclofenac. The drug was initially developed to treat pain and inflammatory disorders in humans; from the early 1990s, Indian farmers began to use it on their livestock.
Indian vultures have always played an important role in the disposal of cattle carcasses, which many Hindus, for religious reasons, refuse to handle. Vultures were reckoned to have scavenged 12 million tonnes of carrion a year, mostly dead cattle.
The use of diclofenac on livestock meant that vultures started to ingest the drug from dead animals. Diclofenac caused renal failure in the birds, and their numbers went into sharp decline.
The dwindling vulture population had an unexpected effect. Unscavenged carcasses provided more food for India’s wild dogs; between 1992 and 2003 their population increased by 7 million. More wild dogs resulted in more dog bites – an extra 40 million bites between 1992 and 2006. More bites by more wild dogs, some of them diseased, led to more cases of rabies – approximately 48,000 additional human deaths, compared with if the vultures had still been around.
Source: Tony Juniper, What Has Nature Ever Done for Us?: How Money Really Does Grow on Trees (2013), pp. 131–6