Vultures, majestic birds of prey with a graceful presence, are often seen circling the roadside in search of a coveted feast. From above, they can detect the slightest sign of rotting meat.
While for some, this image represents the natural efficiency of the food chain, for others, it is a reminder of the fragility of life and the laws of nature.
And, despite the annoyance that seeing them in action may cause us, we must not forget that vultures eat and destroy millions of kilograms of putrefied meat, which can represent a serious threat to public health.
A bomb-proof digestive system
Vultures have a worldwide distribution and include twenty-three different species in the falconiform order. They are known for their ability to consume highly decaying meat from almost any dead vertebrate without suffering toxic effects, an ability that has fascinated the scientific community for centuries.
To eat their prey, these animals insert their beaks into the animal’s natural openings, especially the anus, which exposes them to a group of bacteria different from those found in decaying meat. They are microorganisms, like Clostridium or Fusobacterium, that live in the excrement of dead animals.
In order to carry out feeding, vultures have developed a unique, resistant digestive system that has evolved over many centuries. On the one hand, they have gastric acid with a very low pH, to which is added the presence, in the stomach chamber, of two different types of bacteria.
A few years ago, a multidisciplinary group of American and Danish scientists analyzed the DNA of the communities of bacteria able to survive in the intestines of American vultures. Analysis of the collected samples detected the presence of only 76 bacteria, compared to 528 different microorganisms present on the animal’s surface. In other words, more than 85% of pathogens are eliminated when passing through the gastric chamber of these birds.
An incredibly fast metabolism
Vultures also have an excellent immune system, which allows them to deal with pathogens that would put the lives of other animals in danger. At the same time, they developed a tolerance to some bacteria and toxins present in the spoiled meat, which gave them more resistance. Among these pathogens are bacteria such as Salmonella or Clostridium common in decaying meat.
As if all this were not enough, the metabolism of vultures is very fast, which limits to a minimum the time that poisons remain in their bodies. This allows these animals to consume a lot of meat quickly and subsequently eliminate toxic substances.
Another fundamental part of your body is the antioxidant defense system, which prevents damage caused by free radicals derived from decaying meat.
In conclusion, the resistance of vultures to spoiled meat is the result of a combination of physiological, evolutionary, and metabolic factors, an interesting and unique phenomenon in the animal kingdom that is still the subject of study and research throughout the world.