Eating what would kill you
Why Don't Vultures Get Ill?
A vulture eats meat that has been dead for days and swarming with bacteria, and walks away perfectly well.
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Step 1 of 5
Rotten meat is full of bacteria.
As soon as an animal dies, bacteria multiply in it and some of them make poisons that would badly harm a person from a mouthful. A vulture eats this daily.
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Step 2 of 5
Vulture acid is extraordinarily strong.
Your stomach acid is strong. A vulture's is many times stronger — close to the acid in a car battery — and it destroys most bacteria and their poisons before they get any further.
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Step 3 of 5
Only the toughest microbes survive the trip.
Some of the survivors would make another animal seriously ill Almost nothing lives through that acid, so a vulture's gut holds a small set of very tough bacteria. Some of them would make other animals ill, and the vulture simply tolerates them.
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Step 4 of 5
The bald head is practical.
Feeding means pushing the head deep inside a carcass. A bare head carries far less away with it, and sunlight on bare skin finishes off much of what is left.
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Step 5 of 5
They keep disease down for everyone.
Vultures clear carcasses fast, before the bacteria can spread to water and other animals. Where vulture numbers collapsed, rates of disease in other animals rose sharply.
Vultures find food by soaring and watching each other. One bird dropping out of the sky brings others from kilometres away.
The short version
A vulture eats rotten meat safely because its stomach acid is strong enough to destroy the bacteria and their poisons.
Try it yourself
Notice how vinegar keeps a pickle from going off. Acid stops bacteria — a vulture just has far more of it.