Vulture stomach acid can neutralise anthrax that would kill other scavengers
With stomach acid around pH 1.0, vultures can safely eat rotting carcasses carrying anthrax, botulinum toxin and hog cholera. They are the only land vertebrates known to depend entirely on scavenging, and where their numbers have crashed, as in India since the early 1990s, feral dogs have multiplied to take their place.
There are 23 living vulture species, split into 16 Old World species across Europe, Africa and Asia and seven in the Americas. The two groups look alike through convergent evolution rather than close kinship. Linnaeus lumped them together, even with the harpy eagle; later scientists moved New World vultures near the storks, a theory partly built on a DNA study that was retracted. A 2021 genetic analysis now places both groups in the same order as hawks and eagles.
They find food in different ways. Old World vultures hunt by sight, while several American species can smell a carcass from as much as a mile up, rare among raptors. Research in 2020 showed some also listen for the sounds of predators killing and hyenas feeding, and watch other scavenging birds. Bare heads help keep them clean at a carcass and regulate temperature, and many cool off by urinating down their legs, which also kills bacteria picked up while feeding. When threatened, New World vultures vomit, mainly to lighten themselves for take-off. The bearded vulture is the one vertebrate that specialises in eating bone.
A group circling in the air is a kettle, one perched is a committee and one feeding is a wake. In ancient Egypt the goddess Nekhbet took vulture form, royal wives wore vulture crowns, and people believed all vultures were female, born without a father, which tied them to motherhood and rebirth.
Their decline is severe. In South Asia, residues of the veterinary drug diclofenac in livestock carcasses caused the collapse, threatening practices such as Parsi sky burials. In Africa, poisoning accounted for 61% of recorded deaths in one study, and poachers sometimes lace elephant carcasses because circling birds alert rangers; 537 vultures were found dead in northern Botswana in June 2019. A 2016 review listed nine species as critically endangered.
Source: Vulture
