Vultures are scavengers, and mostly feed on carcasses of dead animals. Their gastric acid is extremely corrosive, allowing vultures to easily digest rotting carcasses infested with many potentially dangerous bacteria. The bald head for which vultures are known is another adaptation to their feeding behaviour, as feathers on the head would be destroyed when the birds enter their heads into fresh carcasses.
For many people, the necrophagous behaviour of vultures is not very attractive, but as consumer of dead animals, vultures prevent the spreading of diseases such as anthrax and rabies and thus fulfill a vital function in the ecosystem.
Vultures occur on all continents except Antarctica and Australia. There are two groups: ‘Old World’ and ‘New World’ vultures. The New World vultures are found in North- and South America and the Old World vultures in Africa, Asia and Europe. The groups are not closely related; the resemblances arose by convergent evolution.
A big difference between old and new world vultures is that old world vultures depend on sight to find food whereas many new world vultures have a very good sense of smell (which is unusual for birds) and can smell dead animals from a distance of up to two kilometers.