How Can Vultures Eat Rotting Flesh Without Getting Sick

It seems every other week there is another food product recalled due to concerns over human health. Chicken, Beef, Lettuce, and many other foods have been ripped from the food supply and take weeks to reappear. During this time, health units around the country begin to warn residents of this condition, or that condition, and many people seem to get sick.

It does seem unfair then that nature has a scavenger around that can seemingly eat whatever it wants, and never seems to get sick. A vulture’s diet consists of mainly rotting, leftover meat from the kills of other predators. Vultures don’t even have to do their own hunting; they rely on whatever is left over from victims of other animals.

Vultures can live quite a long time, up to twenty-five years, and were once a common sight throughout human populated areas. These birds often stay together in family groups, and you are likely familiar with the stereotypical vultures hovering over a soon to be deceased victim. They seem to eat everything and anything they come across, and never seem to get sick!

Are vultures immune to everything?

Vultures like any other animal are susceptible to infection from a variety of sources, so they are unfortunately not immune to everything. Vultures have an incredible well adapted body that helps to ensure that they don’t fall victim to the viral or bacterial agents that lurk within. As far as we know, the vulture’s body is adapted using both genetic changes, and changes in the types of bacteria that it hosts on its own body.

From time to time you may encounter a person who shaves their head and refuses to have facial hair due to their feeling that it is simply easier to be clean without it. It seems that vultures agree, and that due to selective evolutionary pressure, the feathers on the head and neck of the vulture seem to have been weeded out. A very plausible reason for the lack of feathers in this region is that if the feathers were present, there is a very real chance that they would harbour bacteria.

Another biological adaptation of the vulture is that of its stomach. The stomach of a vulture is extremely acidic, orders of magnitude more acidic than a human. It is thought that this increase in acidity helps to ensure that anything the vulture consumes that could hurt it is destroyed once it reaches the stomach.

Even if the vulture’s stomach is safe, why doesn’t their skin get infected?

As with humans, a vulture’s skin hosts a plethora of bacterial agents. When a human consumes yogurt, the majority of the bacteria consumed are considered to be “good” bacteria. Good bacteria for a vulture is of a different variety than ours.

In fact, the “good” bacteria for a vulture is often the very same bacteria that is found in rotting meat. As a result, their skin, and digestive tract is covered in these bacteria. In this way vultures have developed mechanisms to ensure that the bacteria they encounter in their normal diet does not pose them any harm.

A vulture’s skin is far more accommodating than the vultures stomach. On a vulture’s face, you can expect to find over five hundred different types of bacteria. In their stomach and by extension their digestive tract, there are far fewer microorganism varieties. Still, the ones that are surviving in the gut are often the very same bacteria that make humans so sick.

Another adaptation that vultures tend to exhibit is that they will defecate on their own legs. While researchers are not yet entirely certain as to why they do this, it has been proposed that vultures will defecate on their own legs as a sort of protective layer. This layer providing both antimicrobial and probiotic properties for their legs.

Does this mean that vultures do not get sick?

Of course, adaptation in nature often comes with trade-offs. Though a vulture is virtually immune to many of the effects of harmful bacteria that we experience, this does not mean that they cannot fall ill. Even biologically safe drugs for humans, such as ibuprofen can be used to poison a vulture.

Another possible route that a vulture may fall ill is when they consume the carcasses of livestock. When livestock is killed by predators, or left unattended, it is possible for a vulture to seize the opportunity for a feast. Livestock are often raised with antibiotics and other medications which are toxic to the animals that consume them.

How are vultures so different from human beings?

Many of a vulture’s adaptations are not all that unique as birds however, and some of these adaptations can be found throughout the subgroup of animals. This means that while the vultures are excellent at not getting sick from eating rotting meat, other birds, especially those closely related to the vulture may also get lucky and not get sick from eating the same food.

Wow! Vultures certainly are amazing!

Vultures are part of a group that form an important part of any ecosystem. Without the cleanup that vultures, and other scavengers do, the carcasses of animals would remain until they were worn down by the weather. Fortunately, with scavengers and microorganisms that help break down these carcasses, these vital resources are returned to the soil, or directly back into the food chain and help to keep the ecosystem healthy.

Vultures, however, suffer from a misconception that they spread disease. This misconception started some time in the early 1900s and continues to this day. Vultures however prevent the spread of disease by consuming these rotting carcasses and preventing them from stagnating in the wild and promoting the growth of sickness causing bacteria.

The disappearance of vultures, or any scavenger species would be disastrous for an ecosystem. Conservation efforts are underway to help them, but you can do your part to by helping to spread the good that vultures bring to an ecosystem and fight the misconception that they are unclean and bringers of disease.

Sources:

http://faculty.college-prep.org/~bernie/sciproject/project/Kingdoms/animals6/orders.htm#bird

https://www.wildlifecenter.org/vulture-facts

https://www.pbs.org/wgbh/nova/nature/vulture-food-poisoning.html

https://www.npr.org/sections/health-shots/2014/11/25/366545524/how-can-vultures-eat-rotten-roadkill-and-survive

https://www.iflscience.com/plants-and-animals/why-vultures-dont-get-food-poisoning/

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