Three decades after it was brought back from the brink of extinction, the rare Indian crocodile known as the gharial is turning up dead by the dozens on the banks of a river called the Chambal. Forest officials are at a loss to explain why.
Since mid-December, the National Chambal Wildlife Sanctuary has confirmed 76 deaths along the river, which begins in the central Indian state of Madhya Pradesh and runs through Rajasthan and Uttar Pradesh.
Gadiraju Sudhakar, a Chambal district forest officer, said the initial post-mortem reports suggested the cause of death to be liver cirrhosis and stomach ulcers. Further tests show lead levels in the liver that “though not toxic, can trigger suppression of the immune system,” Mr. Sudhakar added. All the more puzzling, other species that inhabit the Chambal River ecosystem, including dozens of fish species on which the gharials feed, appear to be healthy.
Follow-up tests on the fish also revealed heightened lead content. But in both the fish and the gharials, the lead levels are below levels considered lethal, the forest official said. Environmentalists are pressing forest officials for answers on the source of the lead and why the crocodiles died while their prey were unaffected.