Teacher:In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Teacher: Now, understand the problem? Solve this instance: Vultures' faces and large intestines are covered with bacteria that is toxic to most other creatures, but these birds of prey have evolved a strong gut that helps them not get sick from feasting on rotting flesh, according to a new study. 
  
 In the first analysis of bacteria living on vultures, the study's researchers found that these scavengers are laden with flesh-degrading Fusobacteria and poisonous Clostridia. As bacteria decompose a dead body, they excrete toxic chemicals that make the carcass a perilous meal for most animals. But vultures often wait for decay to set in, giving them easy access to dead animals with tough skins. 
  
 Moreover, vultures will often pick at a dead animal through its back end — that is, the anus — to get at the tasty entrails. Their diet may be filled with toxic bacteria and putrid feces, but vultures are apparently immune to these deadly microbes, the researchers said. [In Photos: Birds of Prey] 
  
 "Our results show there has been strong adaptation in vultures when it comes to dealing with the toxic bacteria they digest," Michael Roggenbuck, a researcher of microbiology at the University of Copenhagen, said in a statement. 
  
 To sample the vultures' bacterial communities — called microbiomes — the team captured and euthanized 26 black vultures (Coragyps atratus) and 24 turkey vultures (Cathartes aura) in Nashville, Tennessee. Autopsies and DNA tests revealed the bacteria that lived on the birds' faces and large intestine. 
  
 Like other vertebrates, vultures had more types of bacteria on their faces than in their guts: 528 different types of microorganisms compared with 76. 
  
 The DNA of their prey was broken down in the vultures' gut bacterial samples, which suggests the birds have harsh chemical conditions in their gastrointestinal (GI) tracts, the researchers found. The acidic GI tract also filters out many microorganisms that live on decaying carrion, so the large intestines have large amounts of Clostridia and Fusobacteria. 
  
 "On one hand, vultures have developed an extremely tough digestive system, which simply acts to destroy the majority of the dangerous bacteria they ingest," Roggenbuck said. "On the other hand, vultures also appear to have developed a tolerance toward some of the deadly bacteria — species that would kill other animals actively seem to flourish in the vulture lower intestine." 
  
 Both Clostridia and Fusobacteria appear to have adapted to the vultures' harsh gut conditions, but may also help the birds by further breaking down nutrients, the researchers said. 
  
 The scientists also examined fecal samples from captive turkey vultures and other birds, such as the red-tailed hawk and African spotted owl, at the Copenhagen Zoo. Although the zoo animals had similar diets, the fecal bacteria from captive vultures more closely resembled the microbiomes of their brethren in the wild than it did their avian relatives in the zoo, the researchers found. 
  
 The vultures' bacterial similarities indicate that their digestive system has more influence on gut bacteria than diet does, the researchers said. 
  
 The findings suggest the relationship between microbes and vulture digestion is more complicated than previously thought, the researchers said. 
  
 "The avian microbiome is terra incognita, but it is not unreasonable to suppose that the relationship between birds and their microbes has been as important in avian evolution as the development of powered flight and song," said co-researcher Gary Graves, of the Smithsonian Institution's National Museum of Natural History. 
  
 The study was published today (Nov. 25) in the journal Nature Communications. 
  
 Follow Laura Geggel on Twitter @LauraGeggel. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science. |||||  
  
 Model (microbial) citizens. (Navesh Chitrakar/Reuters) 
  
 Have you thanked a vulture today? It turns out that they're getting rid of an awful lot of dangerous bacteria for us. According to new research published Tuesday in Nature Communications, the vulture has a gut designed to kill off the bacteria that thrive on the carrion they crave. When they chow down, they remove the dangerous microbes from the ecosystem -- and if we can learn more about how the vultures manage this feat, we might be able to harness their skills in our own fights against bacterial infections. 
  
 In the past few years, new technology has helped to unlock the secrets of the microbiome -- the bacterial communities that thrive around, on, and in all of us. But little has been done to investigate the bird microbiome. 
  
 "If you're going to study any kind of bird's microbiome, we figured, vultures would be a great place to start," said study co-author Gary Graves, the curator of birds for the Smithsonian National Museum of Natural History. "It's a microbially rich environment, to say the least." 
  
 That's because of the bird's dietary habits: You've probably seen a vulture picking at roadkill at least once in your life. But it gets even more gross than that. 
  
 To tear into the rotting carcasses, they usually stick their beaks into the anus of their prey. It's the easiest opening, but exposes them to an extra set of nasty bacteria: In addition to the microbes that thrive in rotting flesh, they also get a taste of whatever bacteria live in the deceased prey's fecal matter. 
  
 Graves and his colleagues didn't know what to expect. They were basically going in with a blank slate. Previous studies had taken small samples of bacteria from different species of birds, but no one had ever sat down to profile the entire microbiome of one -- let alone one of the dirtiest birds in the business. 
  
 And it turns out that in some ways, vultures have a microbiome in reverse -- in comparison to humans, anyway. Humans have much more bacterial diversity in their stomachs and mouths than they do on the surface of their skin. We carry multitudes of beneficial bacteria inside us, with our own colonies vastly outnumbering any bacteria we might pick up from the outside world. 
  
 But vultures have dirty, dirty faces -- and shockingly clean guts. The researchers found an average of 528 kinds of bacteria on the vulture faces they sampled, but only 76 kinds of bacteria in their guts. 
  
 "They're sticking their heads into decaying carcasses, so it's not surprising that their faces have so many kinds of bacteria," Graves said. "But when you get to the lower intestine, it's dominated by a small number of very common bacteria. There's a huge reduction from what they actually consumed." 
  
 So during their digestive processes, vultures must kill off the vast majority of the microbes they consume. It's possible that most of the bacteria just can't compete with the champion few that survive. 
  
 The species that continue to thrive in their guts are ones that cause a lot of problems for humans. Clostridia and Fusobacteria are the winners of the vulture gut showdown. The former includes bacteria that causes botulism, gangrene, and tetanus -- dangerous pathogenic infections for humans. Fusobacteria contribute to gum disease and ulcer formation, and may also be involved in some cases of colon cancer. But vultures, whose guts are teeming with the deadly microbes, don't suffer from bleeding gums or rotting limbs. So if scientists can figure out how vultures manage to tolerate those microbes, they might be able to give humans the same skill. 
  
 So it's possible that these gross birds will actually save lives one day. But really, Graves said, they already do. 
  
 "People oftentimes don't recognize the enormous ecosystem services that vultures offer to humans," he said. "It's a free, mobile sanitation department. They're discarding and consuming and getting rid of millions of pounds of decaying flesh that could threaten public health." And now we know that they also kill off most of the microbes instead of passing them back into the ecosystem. 
  
 Vultures definitely deserve our appreciation -- but it's probably best not to show your thanks with a smooch. At least not one on the mouth. |||||
Student:
Vultures eat all kinds of nasty stuff that humans can't (and wouldn't if we could). But how do they survive living off the rotting flesh of roadkill? Researchers set out to answer that query by examining the guts of 24 turkey vultures and 26 black vultures trapped and killed in Tennessee. Expecting to find plenty of bacteria as in human intestines, scientists were surprised to find ... poisons. The first, fusobacteria, is known to cause blood infections in humans, while the second, clostridium, "produces deadly botulism toxins," NPR reports. In vultures, the poisons appeared ineffective. Researchers also found "harsh chemical conditions" inside the birds' gastrointestinal tracts, LiveScience reports; vulture stomach acid is anywhere from 10 to 100 times stronger than that of humans. Scientists guess the vultures' "extremely tough" digestive systems developed an immunity to the toxins, which may in turn help break down other nasty bacteria during digestion. "I think it's mind-boggling that organisms that are perceived as very bad for you seem to be very useful for other biological creatures," a researcher says. "It is not unreasonable to suppose that the relationship between birds and their microbes has been as important in avian evolution as the development of powered flight and song," another adds. The Washington Post reports vultures help kill dangerous microbes before they pass back into the ecosystem, and adds that understanding their immunity could help humans fight our own bacterial infections. (Click to find out what scientists learned about vultures when they left human bodies to decompose in a field.)