For thousands of years, members of the Zoroastrian faith of South Asia have relied on vultures to help in their burial rites. Known as a “sky burial,” the custom was described by Herodotus 2,500 years ago. Today, Meera Subramanian reports for Science and Spirit, the ancient culture and customs are being threatened as the population of South Asian vultures faces extinction. The birds have proven incapable of ingesting diclofenac, a drug that was used to treat an estimated 5 million animals annually, and some scientist believe that extinction is inevitable. The government has banned the drug in livestock, imposing a gradual phaseout, but many scientists believe the efforts are ineffective. Since the religion bans both cremation and burial, the Zoroastrian community is already facing a crisis of how to care for their dead.