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Who ya callin’ bird brain?

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The toolmaking New Caledonian crow is smart, but scientists haven’t reached a consensus on how they handle abstract thinking. (Gavin Hunt)

 

By Kiona Smith-Strickland June 22 at 3:46 PM

 

Are crows the smartest animals of all?

Many scientists think that corvids — the family of birds that includes crows, ravens, rooks and jays — may be among the most intelligent animals on Earth, based on their ability to solve problems, make tools and apparently consider both possible future events and other individuals’ states of mind.

“There’s a lot of research that has been done with both ravens and crows because they are such intelligent species,” said Margaret Innes, an assistant curator at the Maryland Zoo in Baltimore.
Even in humans, defining and measuring intelligence is difficult, and it’s more complicated in other species, which have very different body shapes and have evolved for their niche in the environment. However, scientists who study cognition have defined a few measures of intelligence: recognizing oneself in a mirror, solving complex problems, making tools, using analogies and symbols, and reasoning about what others are thinking.
For a long time, biologists expected most of these mental feats to be unique to primates. The great apes — chimpanzees, orangutans and gorillas — succeed at nearly all of these tasks, from making and using tools to learning large vocabularies of symbols, as well as recognizing themselves in mirrors
.

Crows: Smart as your average 7-year-old?

In this study by the University of Auckland and the University of Cambridge, crows drop objects into tubes filled with water, raising the water level and obtaining a food reward. Researches found that this species of crows can solve a science puzzle about as well as the average 7-year-old kid. (University of Auckland, University of Cambridge)

 

A select few other mammals also meet most of the accepted criteria for intelligence. Dogs and dolphins, for instance, are very good at tasks involving social intelligence, such as communication, conflict resolution and reasoning about what others are thinking. Dolphins are also capable of basic tool use — for instance, carrying sea sponges in their mouths to shield their noses from scrapes and bumps as they forage on the ocean floor.
However, the greatest intellectual rival to the brainy apes may be a noisy scavenger with a sharp beak, bright eyes and a brain about the size of a walnut: the crow and its corvid relatives.

Clever problem-solvers

Crows and ravens are clever problem-solvers, expert toolmakers and adept social movers, but scientists haven’t reached a consensus about how corvid minds handle abstract thinking or how closely their mental processes resemble those of humans.
Researchers from the University of Iowa and Lomonosov Moscow State University in Russia reported early this year that crows can use analogies to match pairs of objects. To reach that conclusion, the scientists trained crows to recognize whether two objects were identical or different, which the birds indicated by pressing one button when shown pictures of objects that matched and a different button when the objects didn’t match. Once all the birds were good at matching objects, researchers showed the crows images of pairs of objects. Some images depicted matched pairs, while others depicted two mismatched objects with different shapes or colors. In response, crows could press buttons to choose between a matched pair or a mismatched pair.
The researchers wanted to see if crows could figure out the relationship between pairs of objects and then choose a pair with the same relationship: matched or mismatched. For instance, a crow looking at a mismatched pair would then select the mismatched pair from their response choices. Nearly 78 percent of the time, the birds succeeded. According to the researchers, the birds recognized that the relationship between the two pairs of objects was the same. In other words, they were making analogies.

Other scientists contend that a type of reasoning less sophisticated than analogies could have produced the same results. For instance, the crows in the analogy test could have simply chosen images with similar characteristics, such as objects of the same color, instead of reasoning about the relationship between the objects, to get the correct answer.

Some behaviors, like those employed in the analogy test, could have more than one explanation, and until recently, scientists could only see what the birds did, then make inferences about the mental processes behind the behavior.

(Russell Gray)

 

Now, researcher John Marzluff and his colleagues at the University of Washington are using positron emission tomography, or PET, scans to study which parts of a crow’s brain are active when it performs such tasks as recognizing friendly and unfriendly birds. And he says that another team of researchers, at the University of California at Davis, is preparing to use the same technique to study the brain activity of New Caledonian crows, a species that makes sophisticated tools. The team hopes to actually see the crows’ brains at work while they’re crafting tools.

Birds’ minds

Corvids seem to understand that other birds have minds like theirs, and their decisions often take into account what others might know, want or intend, according to several studies of crows, ravens and jays. Psychologists call this a theory of mind, and it’s a fairly sophisticated cognitive ability. Humans don’t develop it until late in childhood. Crows and their fellow corvids are social animals, much like primates, so theory of mind probably offers significant evolutionary advantages.
For one thing, it may help prevent food theft. Crows and ravens often hide food in caches and retrieve it later. “You can actually see them watching both the other birds that they are with and the humans, and if they sense that they have been seen, they will take that food and they’ll go and hide it somewhere else,” Innes said of the Maryland Zoo’s ravens. The birds appear to realize that watchers will know where they’ve hidden the food and might use that knowledge to steal it later.
Studies of several corvid species have documented this re-caching, as it is called. Skeptics of the birds’ advanced intelligence say simpler mental processes might prompt re-caching, such as making an association between being seen and later having a cache stolen.
Innes, however, is convinced that the re-caching is a sign that ravens have a theory of mind, based on her observation of re-caching behavior in ravens at the Maryland Zoo. “Definitely,” she said. “I think it definitely indicates that.”
Other test results are harder to dismiss as simple association. When researchers in Austria hid food behind a partition, ravens found it, apparently by noticing where the humans were looking and following their gazes to the hidden food. “You’re using the person’s gaze to infer information about something you can’t see,” Marzluff said.
Brain imaging studies could settle the question, Marzluff said, because advanced cognition in all animals uses different areas of the brain than simpler associative learning.

Feathered craftsmen

Corvids’ toolmaking is much more clearly the product of sophisticated cognition, according to biologists who study them.
Several animals use found objects to get food, such as otters and sea gulls that use rocks to crack shellfish, and apes that use sticks to fish termites out of nests. But deliberately crafting tools is a much more sophisticated skill. Only four species are known to actually make tools: humans, chimpanzees, orangutans — and New Caledonian crows. Although other corvid species have learned to make and use tools in labs, only the crows found on the Pacific island of New Caledonia have been found to actually make tools in the wild.
With their beaks, the crows sharpen forked twigs into hooks for scooping larvae and worms out of holes in wood. The crows often spend more than a minute finding the right stick and then sculpting it into the right shape. Even chimpanzees don’t craft their tools so meticulously, and some researchers say that the crows’ work is on par with very early human tools such as spears and sharpened digging sticks.
New Caledonian crows even take steps to avoid losing their carefully crafted tools. Biologists recently discovered that the birds sometimes stash their hooks in holes, or simply stand on them, when they aren’t in use. The crows are especially careful when the risk of losing their tools is greatest, such as when the birds forage in high branches.
The aptitude for toolmaking is probably an instinct for most corvids, as it is for humans. Corvids use found objects as tools — ravens and crows, for example, drop nuts onto flat rocks to crack the shells — and nearly all corvids seem to have a knack for solving physical problems. In one set of experiments, captive crows figured out how to bend wires into hooks to retrieve food from a tube. And captive rooks, close relatives of crows and ravens, have done the same thing.
It’s unsurprising that chimpanzees and orangutans share so many abilities with humans, because they are very closely related to us, but it’s striking that corvids share so many skills once believed to set humans apart. After all, birds and mammals have spent the last 300 million years evolving on different paths, which produced very different brain structures and bodies.
Parts of the brain that evolved earlier than 300 million years ago, such as the primitive structures in the brainstem that control basic bodily functions, look the same in most animals, including primates and corvids. But structures that developed more recently, like those involved in cognition, are organized very differently in birds than are they are in mammals.
Mammalian brains have evolved with what is called a laminar structure, in which brain cells are organized in six layers that make up the cerebral cortex, or forebrain. The cerebral cortex handles cognitive tasks, and it’s especially well developed in humans and our fellow apes, as well as other intelligent animals such as dolphins and dogs. In the bird brain, a structure called the nidopallium caudolaterale handles cognitive tasks, and it’s especially well developed in corvids.
“All three of those animals have very large forebrains relative to the rest of their brains, for their particular group,” Marzluff said. “Certainly the forebrain of a bird and a mammal differ, but they have the same sorts of functions — that is, you know, higher-level thought and processing of sensory information.”
In birds’ brains, cells form clusters called nuclei instead of layers. For years, biologists held that the layered cerebral cortex gave mammals some cognitive advantages, but research on corvids has cast doubt on that assumption.

Bird brains

That such distantly related animals with such different brains could evolve such similar abilities is surprising, but when two different species face similar evolutionary pressures, natural selection can lead to similar traits. Biologists call this convergent evolution, and it’s the same process by which birds and bats both evolved wings. At some point, biologists say, the ancestor of today’s corvids must have found itself in an ecological niche where intelligence boosted the odds of survival, so corvid brains evolved with cognitive abilities similar to those of primates.
Convergent evolution may have led to similar wiring despite the differences in physical structure between bird and mammalian brains. The network of connections between areas of the brain looks very similar in corvids and primates, and one recently published paper compared bird and primate brains to Apple and PC computers. “At one level of analysis, they do the same things in a similar way, but viewed from another perspective, their operating systems are indeed different,” wrote the author, Cambridge University psychologist Nicola Clayton.
In the coming years, the differences and similarities between corvids’ mental operating systems and those of mammals will be analyzed with brain imaging. At that point, said Marzluff, we may have “some of those answers” to the question of how smart crows really are.

Florida Beachgoers Warned About Deadly Bacteria — That’s Also Found in Raw Shellfish

Korin MillerJune 15, 2015

Eight people have been infected by vibrio vulnificus in Florida this year, and two people have died — one from eating raw seafood and another from “multiple exposures” to the bacteria. (Photo: Getty Images)

If you’ve eaten at a restaurant that serves raw seafood, you’ve probably noticed this warning on the menu, or something similar: “Eating raw or undercooked shellfish can put you at a higher risk of foodborne illness.”

Before you brush off the message, consider this: The state of Florida has issued a warning about vibrio vulnificus, an often deadly bacteria that can be transmitted by eating undercooked or raw shellfish such as oysters, clams, or crabs.

Eight people have been infected by the bacteria in Florida this year, and two have died — one from eating raw seafood and another from “multiple exposures” to the bacteria. (The bacteria killed at least seven people in Florida last year, but the state says that number is underreported.)

Vibrio vulnificus can also be contracted by wading in bacteria-infected water with an open wound, but ingesting raw seafood is by far the biggest culprit, infectious disease specialist Dr. Amesh A. Adalja, an assistant professor at the University of Pittsburgh Medical Center, tells Yahoo Health.

Most people who contract this bacteria will experience vomiting, diarrhea, and abdominal pain, but it can also infect the bloodstream, causing fever, chills, decreased blood pressure, and blistering skin lesions.

This bacteria also has a high mortality rate. According to the Centers for Disease Control and Prevention, vibrio vulnificus bloodstream infections are fatal 50 percent of the time.

Before you panic, know this: Most people who died from vibrio vulnificus had liver disease or had compromised immune systems. However, anyone can become infected.

Related: Salmonella Outbreak Linked to Raw Sushi

Vibrio vulnificus is most common in warm waters in Gulf states, Adalja says, but he points out that 100 percent of Chesapeake Bay oysters have vibrio vulnificus in them. “It’s not uncommon; just not everybody who comes into contact with it gets infected,” he says.

According to Adalja, some people may be genetically predisposed to infection, adding, “The more raw shellfish you eat, the more likely you are to get vibrio vulnificus.”

Michael Doyle, director of the Center for Food Safety at the University of Georgia, tells Yahoo Health that you should be wary of eating raw oysters in general. “It’s considered to be a potential high risk, whether you’re immunocompromised or not,” he said.

However, he says, there is one way you can make sure your raw shellfish is safe: Look for foods that undergo high-pressure processing. This process inactivates harmful microbes that could be in your shellfish, including vibrio vulnificus, but doesn’t kill the oysters. “You still have a fresh flavor, but they’re pasteurized,” Doyle says, noting that more restaurants are buying these types of oysters.  

If you experience symptoms of vibrio vulnificus infection after eating oysters or raw shellfish, call your doctor immediately. “This can quickly spread systemically,” says Adalja. “Getting antibiotics quickly is crucial.”

How a history of eating human brains protected this tribe from brain disease

By Sarah Kaplan June 11 at 6:57 AM

 

 

A real human brain is displayed in the 2001 interactive exhibit “Brain: The World Inside Your Head” at the Smithsonian’s Arts and Industries Building in Washington. (Andrea Bruce Woodall/The Washington Post)

 

The sickness spread at funerals.
The Fore people, a once-isolated tribe in eastern Papua New Guinea, had a long-standing tradition of mortuary feasts — eating the dead from their own community at funerals. Men consumed the flesh of their deceased relatives, while women and children ate the brain. It was an expression of respect for the lost loved ones, but the practice wreaked havoc on the communities they left behind. That’s because a deadly molecule that lives in brains was spreading to the women who ate them, causing a horrible degenerative illness called “kuru” that at one point killed 2 percent of the population each year.
The practice was outlawed in the 1950s, and the kuru epidemic began to recede. But in its wake it left a curious and irreversible mark on the Fore, one that has implications far beyond Papua New Guinea: After years of eating brains, some Fore have developed a genetic resistance to the molecule that causes several fatal brain diseases, including kuru, mad cow disease and some cases of dementia.
The single, protective gene is identified in a study published Wednesday in the journal Nature. Researchers say the finding is a huge step toward understanding these diseases and other degenerative brain problems, including Alzheimer’s and Parkinson’s.
The gene works by protecting people against prions, a strange and sometimes deadly kind of protein. Though prions are naturally manufactured in all mammals, they can be deformed in a way that makes them turn on the body that made them, acting like a virus and attacking tissue. The deformed prion is even capable of infecting the prions that surround it, reshaping them to mimic its structure and its malicious ways.
The prions’ impact on their hosts is devastating and invariably fatal. Among the Fore, the prions riddled their victims’ brains with microscopic holes, giving the organ an odd, spongy texture. In cattle, prions cause mad cow disease — they are responsible for the epidemic in Britain of the late ’80s and ’90s that required hundreds of thousands of cattle to be destroyed. They have been linked to a bizarre form of fatal insomnia that kills people by depriving them of sleep. And they’re the source of the degenerative neurological disorder Creutzfeldt-Jakob disease (CJD), characterized by rapid dementia, personality changes, muscle problems, memory loss and eventually an inability to move or speak.
The vast majority of prion-diseases are “sporadic,” seemingly appearing without cause. But a lead author of the Nature study, John Collinge, said in an interview with Nature that a portion of cases are inherited from one’s parents, and an even smaller percentage are acquired from consuming infected tissue. Variant CJD, often called the “human mad cow disease,” is caused by eating beef from infected cows.
Prions are especially insidious because there’s no way of stopping them, science writer D.T. Max, author of a book on prions and fatal familial insomnia, told NPR in 2006. In the hierarchy of pathogens, they’re even more elusive and difficult to quash than a virus. They can’t be treated with antibiotics or radiation. Formalin, usually a powerful disinfectant, only makes them more virulent. The only way to clean a prion-contaminated object is with massive amounts of extremely harsh bleach, he said. But that technique isn’t helpful in treating a person who has already been infected.
The study by Collinge and his colleagues offers a critical insight into ways that humans might be protected from the still-little-understood prions. They found it by examining the genetic code of those families at the center of the Fore’s kuru epidemic, people who they knew had been exposed to the disease at multiple feasts, who seemed to have escaped unscathed.
When the researchers looked at the part of the genome that encodes prion-manufacturing proteins, they found something completely unprecedented. Where humans and every other vertebrate animal in the world have an amino acid called glycine, the resistant Fore had a different amino acid, valine.
“Several individuals right at the epicenter of the epidemic, they have this difference that we have not seen anywhere else in the world,” Collinge told Nature.
That minute alteration in their genome prevented the prion-producing proteins from manufacturing the disease-causing form of the molecule, protecting those individuals from kuru. To test whether it might protect them from other kinds of prion disease, Collinge — the director of a prion research unit at University College London — and his team engineered the genes of several mice to mimic that variation.
When the scientists re-created the genetic types observed in humans — giving the mice both the normal protein and the variant in roughly equal amounts — the mice were completely resistant to kuru and to CJD. But when they looked at a second group of mice that had been genetically modified to produce only the variant protein, giving them even stronger protection, the mice were resistant to every prion strain they tested — 18 in all.
“This is a striking example of Darwinian evolution in humans, the epidemic of prion disease selecting a single genetic change that provided complete protection against an invariably fatal dementia,” Collinge told Reuters.
The Fore aren’t the only people to demonstrate prion resistance. More than a decade ago, Michael Alpers — a specialist on kuru who has studied the Fore since the 1960s and was a co-author of the Nature study — conducted similar research on prion protein genes in humans worldwide. In a study published in Science, he found that people as far-flung as Europe and Japan exhibited the genetic protection, indicating that cannibalism was once widespread and that prehistoric humans probably dealt with waves of kuru-like epidemics during our evolution.
But the gene found in the Fore is special because it seems to render mutant prion-producing proteins (the kind that would be passed down from one’s parents, causing inherited prion diseases) incapable of producing any kind of prion whatsoever. It also stops the wild-type protein — the phenotype that most people have — from making malformed prions.
Scientists say that the benefits of this discovery don’t stop at prion diseases, which are relatively rare — only about 300 cases are reported each year in the United States. According to Collinge, the process involved in prion diseases — prions changing the shape of the molecules around them and linking together to form long chains called “polymers” that damage the brain — is probably responsible for the deadly effects of all kinds of degenerative brain illnesses: Alzheimer’s, Parkinson’s and dementia chief among them.
According to the World Health Organization, there are 47.5 million people worldwide living with dementia. An additional 7.7 million are diagnosed each year.
If Collinge and his colleagues can understand the molecular mechanisms by which prions do their work — and how the prion-resistant gene stops them — they might better understand the misshapen proteins that are afflicting millions with those other degenerative brain illnesses.
Eric Minikel, a prion researcher at the Broad Institute in Cambridge, Mass., who was not involved in the study, was impressed by the finding.
“It is a surprise,” he told Nature. “This was a story I didn’t expect to have another chapter.”

Scientists just found soft tissue inside a dinosaur fossil. Here's why that's so exciting.

http://www.vox.com/

Updated by Joseph Stromberg on June 9, 2015, 11:00 a.m. ET

A theropod claw fossil, in which microscopic structures resembling red blood cells were found. (Laurent Mekul)

 

Dinosaur fossils, it was long thought, are simple objects. The fossilization process leaves the overall shape of a dinosaur's bones intact, but all the microscopic structures inside them — the blood cells, connective fibers, and other sorts of soft tissue — inevitably decay over time.
But that view is changing — and it's possible that many ancient fossils may preserve more detail than meets the eye. The sort of biological tissue now being found in some fossils could tell us about dinosaur anatomy, behavior, and evolution in ways that weren't possible just a few years ago.

(Sergio Bertazzo)

The photo above, from a new study published today in Nature Communications and led by Sergio Bertazzo of Imperial College London, shows an extremely zoomed-in view of a 75-million-year-old theropod claw, taken from the London Natural History Museum's collection. When researchers scraped tiny pieces off the fossil and looked at them under an electron microscope, they found tiny structures that look a lot like collagen fibers present in our own ligaments, tendons, and bones.

Related This paleontologist just snuck a marriage proposal into his paper on a new dinosaur
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In other dinosaur fossils, the researchers found features that resemble red blood cells. Tests showed that they have a similar chemical composition to the blood of an emu (a bird thought to be a relatively close relative to dinosaurs).

  (Bertazzo et. al. 2015)

The idea that dinosaur fossils might harbor soft tissue first surfaced about a decade ago, when paleontologist Mary Schweitzer found evidence of blood cells preserved inside T. rex fossils.
But what's so exciting about this new study is that the fossils used, unlike Schweitzer's, aren't particularly well-preserved. Susannah Maidment, one of the paleontologists who worked on the paper, called them "crap" specimens. If they have preserved soft tissue inside them, it could be a sign that thousands of other fossils in museum collections do too.

How paleontologists found blood inside dinosaur fossils

(ScottRobertAnselmo)

For hundreds of years, most paleontologists never considered that their fossils might preserve these sorts of microscopic soft-tissue features. It was assumed that the proteins and other molecules they're made of would deteriorate in just a few million years.
What's more, looking inside them to confirm this would require that people damage the fossil, either by breaking it open or by dissolving the hard, mineralized outside, as Schweitzer did with her T. rex. "No right-thinking paleontologist would do what Mary did with her specimens," paleontologist Thomas Holtz told Smithsonian for a 2006 story on Schweitzer's discovery. "We don’t go to all this effort to dig this stuff out of the ground to then destroy it in acid."

Soft tissue extracted from a T. rex fossil by Schweitzer appeared to contain blood cells. (Schweitzer et al., 2005/Science)

Schweitzer did so after a veterinarian at a conference happened to see microscope slides of T. rex bone slices and observed that there were red blood cells inside it. But her claim remained controversial among paleontologists — even after her 2006 paper, which presented more thorough testing.
More recent chemical analysis has provided further evidence that the
T. rex bones do indeed contain blood cells, and Schweitzer has since found soft tissue preserved inside an 80-million-year-old hadrosaur. It's still unclear exactly how this soft tissue is able to survive, but some hypothesize that iron molecules might bind to proteins in the tissue, making it more stable.
This newest paper, conducted with weathered, run-of-the-mill fossils rather than pristine ones, suggests that this process might be the rule, not the exception. If so, these findings could be the first of many to come.

Dinosaur blood and proteins could tell us about their behavior and evolution

(Vaderxl/Dinopedia)

You can only learn so much about an organism from its bones. As much as we've discovered from the hundreds of thousands of dinosaur fossils excavated around the world, we're still debating whether dinosaurs were warm- or cold-blooded and how many of them had feathers.
Peering inside these dinosaurs' bones — to look at their blood cells, connective tissue, and other microscopic features — could dramatically improve our understanding of their biology as a whole. The structure of their blood cells, for instance, could hint at their behavior and physiology in ways that their bones simply can't.
The tissue might help scientists better understand evolutionary relationships between species
The new information might also help scientists better understand evolutionary relationships between species. In the study, researchers found that the proteins inside the collagen-like fibers are well-preserved, with the specific sequence of amino acids that they're built from largely intact. Amino acid sequences in proteins gradually evolve over time and vary from species to species, somewhat like DNA — so analyzing them in dinosaurs could lead to better knowledge about the evolutionary relationships between them and other species, like birds.
But there's one thing we can't do with this soft tissue: extract dinosaur DNA and make Jurassic Park a reality. Compared with collagen fibers and red blood cells, DNA is much, much smaller and more fragile.
Perhaps DNA could also be more readily preserved than thought. But scientists currently estimate that it has a half-life of just 521 years, and dinosaurs largely died off 65 million years ago.