These feathery scavengers have one of the toughest guts on the
planet, that is how. Scientists said on Tuesday that their analysis
of two species of North American vultures showed that the birds
possess a ferociously acidic digestive system and intestines loaded
with two fiendish kinds of bacteria.
In the black vulture and the turkey vulture, this gastrointestinal
one-two punch effectively knocks out much of the potential
disease-causing microbes populating the carrion - animal carcasses -
that these birds eat, the researchers said.
"The vulture gastrointestinal passage is a hostile environment,"
said microbiologist Lars Hestbjerg Hansen of Aarhus University in
Denmark, one of the researchers in the study published in the
journal Nature Communications.
"These vultures will consume virtually any dead vertebrate - mammal,
bird, snake, fish. They prefer recently deceased organisms rather
than extremely putrid carcasses. For example, day-old road-killed
deer are perfect," said ornithologist Gary Graves of the Smithsonian
Institution's National Museum of Natural History in Washington,
another of the researchers.
The researchers examined the community of microbes, or microbiome,
living in the gut of 50 vultures of the two species.
The most common gut bacteria - Clostridia and Fusobacteria - turned
out to be microbes that are widely pathogenic to other animals. For
example, Clostridia can cause a world of woes - botulism, gangrene
and tetanus - in people.
The researchers also found that the stomach acid of vultures is very
strong and kills a good deal of the bacteria gobbled up by the birds
with the rotting meat.
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"The majority of the food-ingested microbes will not survive these
harsh conditions," said University of Copenhagen microbiologist
Michael Roggenbuck, another of the researchers.
The turkey vulture, often called a buzzard, is covered with black
feathers, has a featherless head with red skin, and boasts a
wingspan of nearly 6 feet (1.75 meters). It is common in many parts
of North America.
The black vulture is slightly smaller, with a wingspan of nearly 5
feet (1.45 meters), black feathers and a wrinkled featherless head
with dark gray skin. It is found throughout the southeastern United
The two are members of a group called the New World vultures that
also includes the huge California condor and Andean condor.
(Reporting by Will Dunham; Editing by Grant McCool)
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