An endearing antelope with a bulbous nose

Saturday, January 27th, 2018

The saiga is “an endearing antelope” that roams Central Asia. Its “bulbous nose gives it the comedic air of a Dr. Seuss character,” Ed Yong says:

It typically wanders over large tracts of Central Asian grassland, but every spring, tens of thousands of them gather in the same place to give birth. These calving aggregations should be joyous events, but the gathering in May 2015 became something far more sinister when 200,000 saiga just dropped dead. They did so without warning, over a matter of days, in gathering sites spread across 65,000 square miles — an area the size of Florida. Whatever killed them was thorough and merciless: Across a vast area, every last saiga perished.

Saiga calf

At first, the team suspected that a new infectious disease had spread through the population, but the pattern of deaths just didn’t fit. The saiga were dying too synchronously and too quickly. Also, all of them had died. “In biology, there’s certain rules, you know?” says Kock. “We accept that sometimes microbes can cause us harm, but not like this. Even very severe viral diseases or anthrax don’t do this. A good proportion of the animals would be fine.”

News of the die-off sparked outlandish explanations about Russian rocket fuel, radiation, and even aliens. But while conspiracy theories raged, a huge international team of scientists, led by Kock, got to work. Vets autopsied as many saigas as they could. Ecologists sampled the soil. Botanists checked the local plants. They couldn’t find any signs of toxins that might have killed the saiga. Instead, the actual culprit turned out to be a bacterium, one that’s usually harmless.

Pasteurella multocida normally lives in the saiga’s respiratory tract, but Kock’s team found that the microbe had found its way into the animals’ blood, and invaded their livers, kidneys, and spleens. Wherever it went, it produced toxins that destroyed the local cells, causing massive internal bleeding. Blood pooled around their organs, beneath their skin, and around their lungs. The saigas drowned in their own bodily fluids.

But that answer just led to more questions. Pasteurella is common and typically harmless part of the saiga’s microbiome. In livestock, it can cause disease when animals are stressed, as sometimes happens when they’re shipped over long distances in bad conditions. But it has never been linked to a mass die-off of the type that afflicted the saigas. What could have possibly turned this docile Jekyll into such a murderous Hyde?

The team considered a list of possible explanations that runs to 13 pages. They wondered if some environmental chemical or dietary change had set the microbe off. They checked if biting insects had transmitted a new infection that interacted with Pasteurella. They considered that Pasteurella might have gone rogue because of an accompanying viral infection, in the same way that Streptococcus bacteria can bloom during a cold, leading to strep throat. “We tested for everything and we couldn’t find anything,” says Eleanor Milner-Gulland from the University of Oxford.

Only one factor fit the bill: climate. The places where the saigas died in May 2015 were extremely warm and humid. In fact, humidity levels were the highest ever seen the region since records began in 1948. The same pattern held for two earlier, and much smaller, die-offs from 1981 and 1988. When the temperature gets really hot, and the air gets really wet, saiga die. Climate is the trigger, Pasteurella is the bullet.

It’s still unclear how heat and humidity turn Pasteurella into a killer, and the team is planning to sequence the bacterium’s genome to find out more.

None more black

Thursday, January 25th, 2018

Blackbirds, Ed Yong explains, aren’t actually all that black:

Their feathers absorb most of the visible light that hits them, but still reflect between 3 and 5 percent of it. For really black plumage, you need to travel to Papua New Guinea and track down the birds of paradise.

Although these birds are best known for their gaudy, kaleidoscopic colors, some species also have profoundly black feathers. The feathers ruthlessly swallow light and, with it, all hints of edge or contour. They make body parts seem less like parts of an actual animal and more like gaping voids in reality. They’re blacker than black. None more black.

By analyzing museum specimens, Dakota McCoy, from Harvard University, has discovered exactly how the birds achieving such deep blacks. It’s all in their feathers’ microscopic structure.

A typical bird feather has a central shaft called a rachis. Thin branches, or barbs, sprout from the rachis, and even thinner branches—barbules—sprout from the barbs. The whole arrangement is flat, with the rachis, barbs, and barbules all lying on the same plane. The super-black feathers of birds of paradise, meanwhile, look very different. Their barbules, instead of lying flat, curve upward. And instead of being smooth cylinders, they are studded in minuscule spikes. “It’s hard to describe,” says McCoy. “It’s like a little bottle brush or a piece of coral.”

Bird of Paradise Ultra-Black

These unique structures excel at capturing light. When light hits a normal feather, it finds a series of horizontal surfaces, and can easily bounce off. But when light hits a super-black feather, it finds a tangled mess of mostly vertical surfaces. Instead of being reflected away, it bounces repeatedly between the barbules and their spikes. With each bounce, a little more of it gets absorbed. Light loses itself within the feathers.

McCoy and her colleagues, including Teresa Feo from the National Museum of Natural History, showed that this light-trapping nanotechnology can absorb up to 99.95 percent of incoming light. That’s between 10 and 100 times better than the feathers of most other black birds, like crows or blackbirds. It’s also only just short of the blackest materials that humans have designed. Vantablack, an eerily black substance produced by the British company Surrey Nanosystems, can absorb 99.965 percent of incoming light. It consists of a forest of vertical carbon nanotubes that are “grown” at more than 750 degrees Fahrenheit. The birds of paradise mass-produce similar forests, using only biological materials, at body temperature.

Legendary was Hacienda Napoles where Pablo Escobar decreed his stately pleasure dome

Monday, January 22nd, 2018

I’m not sure what led Steve Sailer to cite a two-year-old National Geographic story about Pablo Escobar’s escaped hippos, but I immediately remembered the story from long, long ago (2003):

Legendary was Xanadu where Kubla Khan decreed his stately pleasure dome. Today, almost as legendary is Florida’s Xanadu…or Pablo Escobar’s 7,400-acre Hacienda Napoles.

Commenter Polearm noted that we nearly filled the United States with the great beasts at the beginning of the 20th Century:

America was withering under a serious meat shortage at the time. Beef prices had soared as rangeland had been ruined by overgrazing, and a crippled industry struggled to satisfy America’s explosively growing cities, an unceasing wave of immigrants, and a surging demand for meat abroad. There were more mouths to feed than ever, but the number of cows in the country had been dropping by millions of head a year. People whispered about the prospect of eating dogs. The seriousness of the Meat Question, and the failure to whip together some brave and industrious solution to it, was jarring the nation’s self-confidence and self-image. It was a troubling sign that maybe the country couldn’t keep growing as fast and recklessly as it had been. Maybe there were limits after all.

Now, though, someone had an answer. The answer was hippopotamuses. One Agricultural Department official estimated that an armada of free-range hippos, set moping through the bayous of Florida, Mississippi, and Louisiana, would easily yield a million tons of meat a year. Already, Representative Broussard had dispatched a field agent on a fact-finding mission. The man, a native of southern Africa, found the Louisiana swamps “wildly dismal and forbidding.” (The “silence strike[s] one with an almost unforgettable horror,” he wrote in his report, titled “Why and How to Place Hippopotamus in the Louisiana Lowlands.”) Still, the place was perfect for hippos. His conclusion: “The hippopotamus would find no difficulty living in Louisiana.”

Apparently, the animals tasted pretty good, too, especially the fatty brisket part, which could be cured into a delicacy that a supportive New York Times editorial was calling, euphemistically, “lake cow bacon.” (“Toughness is only skin deep,” another reporter noted.) Congressman Broussard’s office was receiving laudatory letters from ordinary citizens, commending his initiative-taking and ingenuity. Several volunteered to be part of the expedition to bring the great beasts back.

In other words, in the encroaching malaise of 1910, it was easy to be gripped by the brilliance of the hippopotamus scheme, to feel hippopotamuses resonating not just as a way of sidestepping catastrophic famine, but as a symbol of American greatness being renewed. Burnham’s generation had seen the railroad get synched across the wild landscape like a bridle and the near solid swarms of buffalo and passenger pigeons get erased. America had dynamited fish out of rivers, dredged waterways, felled and burned forests, and peeled silver from the raw wreckage of what had once been mountains. The frontier was now closed. So much had been accomplished and so much taken. It was clear that a once boundless-seeming land did have boundaries, and with those limits revealed, you couldn’t help but feel like you were drifting listlessly between them. There was a sense in the country of: Now what? And, lurking beneath that: What have we done?

Another commenter, the one they call Desanex, shared one of his favorite paintings, The Hippopotamus and Crocodile Hunt by Peter Paul Rubens:

The Hippopotamus and Crocodile Hunt by Peter Paul Rubens

Too many cypress knees

Saturday, January 13th, 2018

Swamp Park, in southeastern North Carolina, is at the northern extreme for American alligators, which means it can get a little cold for the cold-blooded reptiles:

At first, [George Howard, the park’s general manager] thought the water had too many cypress knees – woody projections from tree roots that are a common sight in swamps.

Then he saw teeth.

Alligator Snout Poking out of Ice

When it’s cold but not icy, the alligators disappear, sinking to the bottom of the swamp for most of the day or burrowing into the mud, Howard said. “You don’t see them, but they’re under there.”

[...]

Right before the surface freezes, they stick their snouts out of the water so they can continue breathing.

Iguanas, by the way, react somewhat differently to the cold:

And in Florida, where temperatures took a rare dip into the 40s last week, iguanas also slowed their bodily functions. But because many are tree dwellers, some just fell to the ground.

It was a repeat of a cold snap in 2010, when the iguana situation caught people similarly unawares.

“Neighbourhoods resounded with the thud of iguanas dropping from trees onto patios and pool decks, reptilian Popsicles that suggested the species may not be able to retain its claw-hold on South Florida,” the Sun-Sentinel’s David Fleshler wrote.

But the story had a happy ending, Fleshler reported. The iguanas “have rebounded, repopulating South Florida neighbourhoods and resuming their consumption of expensive landscaping.”

By the way, the term brumation was coined in 1965, so reptiles could have their own term for hibernation.

Yes, dolphins are smart

Friday, January 12th, 2018

The more we study dolphins, the brighter they turn out to be:

At the Institute for Marine Mammal Studies in Mississippi, Kelly the dolphin has built up quite a reputation. All the dolphins at the institute are trained to hold onto any litter that falls into their pools until they see a trainer, when they can trade the litter for fish. In this way, the dolphins help to keep their pools clean.

Kelly has taken this task one step further. When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on. This behaviour is interesting because it shows that Kelly has a sense of the future and delays gratification. She has realised that a big piece of paper gets the same reward as a small piece and so delivers only small pieces to keep the extra food coming. She has, in effect, trained the humans.

Her cunning has not stopped there. One day, when a gull flew into her pool, she grabbed it, waited for the trainers and then gave it to them. It was a large bird and so the trainers gave her lots of fish. This seemed to give Kelly a new idea. The next time she was fed, instead of eating the last fish, she took it to the bottom of the pool and hid it under the rock where she had been hiding the paper. When no trainers were present, she brought the fish to the surface and used it to lure the gulls, which she would catch to get even more fish. After mastering this lucrative strategy, she taught her calf, who taught other calves, and so gull-baiting has become a hot game among the dolphins.

Dolphins are clever in the wild, too:

In an estuary off the coast of Brazil, tucuxi dolphins are regularly seen capturing fish by “tail whacking”. They flick a fish up to 9 metres with their tail flukes and then pick the stunned prey from the water surface. Peale’s dolphins in the Straits of Magellan off Patagonia forage in kelp beds, use the seaweed to disguise their approach and cut off the fishes’ escape route. In Galveston Bay, Texas, certain female bottlenose dolphins and their young follow shrimp boats. The dolphins swim into the shrimp nets to take live fish and then wriggle out again – a skill requiring expertise to avoid entanglement in the fishing nets.

Dolphins can also use tools to solve problems. Scientists have observed a dolphin coaxing a reluctant moray eel out of its crevice by killing a scorpion fish and using its spiny body to poke at the eel. Off the western coast of Australia, bottlenose dolphins place sponges over their snouts, which protects them from the spines of stonefish and stingrays as they forage over shallow seabeds.

This earns a “wow”:

At a dolphinarium, a person standing by the pool’s window noticed that a dolphin calf was watching him. When he released a puff of smoke from his cigarette, the dolphin immediately swam off to her mother, returned and released a mouthful of milk, causing a similar effect to the cigarette smoke.

Their ability to learn a language is impressive:

By human definition, there is currently no evidence that dolphins have a language. But we’ve barely begun to record all their sounds and body signals let alone try to decipher them. At Kewalo Basin Marine Laboratory in Hawaii, Lou Herman and his team set about testing a dolphin’s ability to comprehend our language. They developed a sign language to communicate with the dolphins, and the results were remarkable. Not only do the dolphins understand the meaning of individual words, they also understand the significance of word order in a sentence. (One of their star dolphins, Akeakamai, has learned a vocabulary of more than 60 words and can understand more than 2,000 sentences.) Particularly impressive is the dolphins’ relaxed attitude when new sentences are introduced. For example, the dolphins generally responded correctly to “touch the frisbee with your tail and then jump over it”. This has the characteristics of true understanding, not rigid training.

I’m reminded of that damn bird, Alex the African Grey parrot, who was no birdbrain, and of Rico the Border Collie.

Raptors are setting fires on purpose

Thursday, January 11th, 2018

Raptors — the black kite, whistling kite, and brown falcon — are intentionally spreading grass fires in northern Australia:

Raptors on at least four continents have been observed for decades on the edge of big flames, waiting out scurrying rodents and reptiles or picking through their barbecued remains.

What’s new, at least in the academic literature, is the idea that birds might be intentionally spreading fires themselves. If true, the finding suggests that birds, like humans, have learned to use fire as a tool and as a weapon.

Gosford, a lawyer turned ethno-ornithologist (he studies the relationship between aboriginal peoples and birds), has been chasing the arson hawk story for years. “My interest was first piqued by a report in a book published in 1964 by an Aboriginal man called Phillip Roberts in the Roper River area in the Northern Territory, that gave an account of a thing that he’d seen in the bush, a bird picking up a stick from a fire front and carrying it and dropping it on to unburnt grass,” he told ABC.

DSfUk3pV4AAtSZ7.jpg large.jpg

“MJ,” a Kimberley, (Western Australia) cattle station caretaker manager … saw kites working together to move a late dry season fire across a river by picking up, transporting, and dropping small, burning sticks in grass, which immediately ignited in several places,” they write. “The experience resulted in an uncontrollable blaze that destroyed part of the station’s infrastructure.”

Bob White, a firefighter in the Northern Territory saw a small group of raptors, likely black kites, “pick up numerous smouldering sticks and transport them ahead of a fire front, successfully helping the blaze spread up a small valley.”

Nathan Ferguson claims to have observed fire spreading about a dozen times in the Northern Territory since 2001. The long-time firefighter is adamant that the birds he’s observed — picking up twigs and starting new fires — were doing so on purpose.

That jibes with the other research Gosford and Bonta dug up. “Most accounts and traditions unequivocally indicate intentionality on the part of three raptor species,” they wrote.

Dogs are not super-cooperative wolves

Tuesday, October 24th, 2017

Dogs are not super-cooperative wolves:

She and her colleagues challenged their canines to a simple task, which other scientists have used on all kinds of brainy animals — chimps, monkeys, parrots, ravens, and even elephants. There’s a food-bearing tray that lies on the other side of their cage, tempting and inaccessible. A string is threaded through rings on the tray, and both of its ends lie within reach of the animals. If an individual grabs an end and pulls, it would just yank the string out and end up with a mouthful of fibers — not food. But if two animals pull on the ends together, the tray slides close, and they get to eat.

All in all, the dogs did terribly. Just one out of eight pairs managed to pull the tray across, and only once out of dozens of trials. By contrast, five out of seven wolf pairs succeeded, on anywhere between 3 and 56 percent of their attempts. Even after the team trained the animals, the dogs still failed, and the wolves still outshone them. “We imagined that we would find some differences but we didn’t expect them to be quite so strong,” Marshall-Pescini says.

It’s not that the dogs were uninterested: They explored the strings as frequently as the wolves did. But the wolves would explore the apparatus together — biting, pawing, scratching, and eventually pulling on it. The dogs did not. They tolerated each other’s presence, but they were much less likely to engage with the task at the same time, which is why they almost never succeeded.

“The dogs are really trying to avoid conflict over what they see as a resource,” says Marshall-Pescini. “This is what we found in food-sharing studies, where the dominant animal would take the food and the subordinate wouldn’t even try to approach. With wolves, there’s a lot of arguing and it sounds aggressive, but they end up sharing. They have really different strategies in situations of potential conflict. [With the dogs], you see that if you avoid the other individual, you avoid conflict, but you can’t cooperate either.”

“Amazingly, no one had ever studied whether carnivores could solve this type of cooperative task, and it’s fun to see that the wolves coordinated,” says Brian Hare from Duke University, who studies dog behavior and the influence of domestication. He has argued that during the domestication process, dogs began using their traditional inherited mental skills with a new social partner: humans.

Simultaneously, dogs perhaps became less attentive to each other, adds Marshall-Pescini. After all, wolves need to work together to kill large prey, and sharing food helps to keep their social bonds intact. But when they started scavenging on human refuse, they could feed themselves on smaller portions by working alone. If they encountered another forager, “maybe the best strategy was to continue searching rather than to get into conflict with another dog,” she says.

But dogs can be trained. When owners raise dogs in the same household, and train them not to fight over resources, the animals start to tolerate each other, and unlock their ancient wolflike skills. This might be why, in 2014, Ljerka Ostojic, from the University of Cambridge, found that pet dogs, which had been trained in search and rescue, had no trouble with the string-pulling task that flummoxed Marshall-Pescini’s dogs.

“It speaks to the fact that living among other dogs, without interaction with humans, is arguably less natural for dogs — as if domestication both refined attention, coordination, and even pro-sociality between species, and weakened social skills within the species,” says Alexandra Horowitz, who studies dog cognition at Barnard College. “A pack of dogs living together, without human intervention, is impaired compared to dogs living with humans.”

Being bitten by an Australian tiger snake is a wholly unpleasant experience

Saturday, September 2nd, 2017

Being bitten by an Australian tiger snake is a wholly unpleasant experience:

Within minutes, you start to feel pain in your neck and lower extremities — symptoms that are soon followed by tingling sensations, numbness, and profuse sweating. Breathing starts to become difficult, paralysis sets in, and if left untreated, you’ll probably die. Remarkably, the venom responsible for these horrifying symptoms has remained the same for 10 million years — the result of a fortuitous mutation that makes it practically impossible for evolution to find a counter-solution.

[...]

The secret to tiger snake venom has to do with its biological target — a clotting protein called prothrombin. This critically important protein is responsible for healthy blood clotting, and it exists across a diverse array of animal species (humans included). Any changes to this protein and the way it works can be catastrophic to an animal, leading to life-threatening conditions such as hemophilia. It’s this vulnerable target that makes the tiger venom so potent, but at the same time, animals are under intense evolutionary pressure to maintain prothrombin in its default, functional state. As Fry explained in a release, if the animals had any variation in their blood clotting proteins, “they would die because they would not be able to stop bleeding.”

Non-permissive even to motorcycles

Monday, August 7th, 2017

American special operations forces famously found themselves riding to war on horseback in Afghanistan in 2001:

When the 5th Special Forces Group’s Operational Detachment Alpha 595 touched down and linked up with warlord Abdul Rashid Dostum — a Soviet-trained ethnic Uzbek military officer who had sided with the Northern Alliance against the predominantly Pashtun Taliban and who ultimately became a highly controversial figure accused of multiple human rights abuses and war crimes — they found his forces already conducting cavalry raids on horseback due to the lack of roads and even established trails in the area.

“Looking back, it was the best means for travel because some of those places we went would have been non-permissive to even motorcycles,” retired U.S. Air Force combat controller Bart Decker, who had served attached to ODA 595, said in 2016.

“It was the wild, wild west,” U.S. Air Force Maj. Mike Sciortino, another former combat controller, who was then serving with the 31st Surgical Operations Squadron, added at the time. “When we first got in, they said we were probably going to ride horses … I had never ridden a horse before. I was like, are these guys serious?”

ODA 595 and Northern Alliance on Horseback in 2001

The whole situation might have been a disaster had it not be for an amazing twist of fate. ODA 595’s commanding officer, U.S. Army Major Mark Nutsch, had grown up on a cattle ranch in Kansas and competed in rodeo events while he studied at Kansas State University. “The guys did a phenomenal job learning how to ride that rugged terrain,” he said in a later interview. “Initially you had a different horse for every move … and you’d have a different one, different gait or just willingness to follow the commands of the rider. … The guys had to work through all of that and use less than optimal gear. … Eventually we got the same pool of horses we were using regularly.”

Chimps are not superhumanly strong

Wednesday, June 28th, 2017

Chimps are not as superhumanly strong as we thought they were:

“There’s this idea out there that chimpanzees are superhuman strong,” says Matthew O’Neill at the University of Arizona in Phoenix. Yet his team’s experiments and computer models show that a chimpanzee muscle is only about a third stronger than a human one of the same size.

This result matches well with the few tests that have been done, which suggest that when it comes to pulling and jumping, chimps are about 1.5 times as strong as humans relative to their body mass. But because they are lighter than the average person, humans can actually outperform them in absolute terms, say O’Neill.

His findings suggest that other apes have similar muscle strength to chimpanzees. “Humans are the odd ones,” he says.

O’Neill’s team has been studying the evolution of upright walking. To create an accurate computer model of how chimps walk, the researchers needed to find out whether their muscles really are exceptionally strong. So they removed small samples of leg muscle from three chimps under general anaesthetic and measured the strength of individual fibres.

The same procedure is used to study human muscles. Comparing the results with the many studies on those revealed that, contrary to the claims of several other studies, there is nothing special about chimp muscle. “Chimpanzee muscle is really no different than human muscle in terms of the force that individual fibres exert,” says O’Neill.

So why, on a pound-for-pound basis, are chimps slightly stronger than humans? The team went on to look at the muscle of chimps that had died of natural causes, which revealed that two-thirds of their muscle consists of fast-twitch fibres, whereas more than half of human fibres are slow-twitch.

[...]

Quite how the myth that chimps are incredibly strong came about is not clear, says O’Neill. But it may have been fuelled by a 1923 study that claimed one chimp could pull nine times its own body weight. Later studies suggested they could only pull two to four times their weight.

A parable of the lessons that can emerge from unfettered science

Tuesday, May 16th, 2017

I was immediately fascinated by the Siberian farm fox experiment and the surprisingly broad domestication phenotype, which notably includes pigmentation.

Marlene Zuk reviews Dugatkin and Trut’s How to Tame a Fox (and Build a Dog) for The New York Times, and ends on this note:

The book, however, is not only about dogs, or foxes, or even science under siege from political interests. It is an exploration of how genes, evolution and then environment shape behavior, and in a way that puts paid simplistic arguments about nature versus nurture. It may serve — particularly now — as a parable of the lessons that can emerge from unfettered science, if we have the courage to let it unfold.

Marlene Zuk wrote Paleofantasy: What Evolution Really Tells Us About Sex, Diet and How We Live.

Researchers find yet another reason why naked mole-rats are weird

Wednesday, May 3rd, 2017

Researchers find yet another reason why naked mole-rats are weird:

For example, instead of generating their own heat, they regulate body temperature by moving to warmer or cooler tunnels, which lowers the amount of energy they need to survive. They’re also known to have what Park calls “sticky hemoglobin,” which allows them to draw oxygen out of very thin air. And because they live underground in large social groups, they’re used to breathing air that’s low in oxygen and high in carbon dioxide.

[...]

To start out, he and his colleagues tested how well the mole-rats fared in a chamber with only 5 percent oxygen, which is about a quarter of the oxygen in the air we breathe, and can kill a mouse in less than 15 minutes.

They watched closely, ready to pull the mole-rats out at the first sign of trouble.

“So we put them in the chamber and after five minutes, nothing. No problems,” Park says. An hour later, there were still no problems.

Five hours later, the researchers were tired and hungry and ready to go home, but the mole-rats could’ve kept chugging along.

“Oh, I think so,” says Park. “They had more stamina than the researchers.”

The animals had slowed down a bit, he says, but were awake, walking around and even socializing.

“They looked completely fine,” he says.

Next, the researchers decided to see how the mole-rats dealt with zero percent oxygen.

“And that was a surprise, too,” he says.

Such conditions can kill a mouse in 45 seconds.

The four mole-rats involved in this leg of the study passed out after about 30 seconds, but their hearts kept beating and — a full 18 minutes later — the mole-rats woke up and resumed life as usual when they were re-exposed to normal air. (The three mole-rats that were exposed for 30 minutes, however, died.)

[...]

When the researchers looked at tissue samples taken from the mole-rats at various times during the oxygen deprivation, they noticed a spike in levels of another sugar, fructose, about 10 minutes in.

“We weren’t looking for it, but bang, fructose goes way up in the blood and then it goes way up in the organs and it gets used by heart and brain,” Park says.

The naked mole-rats appear to have the option of switching fuels from glucose, which requires oxygen to create energy, to fructose, which doesn’t.

Humans are capable of storing and using fructose in the liver and kidney, but as Park explains, we don’t have enough of the correct enzyme to create energy directly from fructose. Nor do we have enough of the proteins necessary to move fructose molecules into the cells of vital organs. Our cells have to convert it into glucose in order to use it.

The cells in the brain, heart, liver and lungs of naked mole-rats are all outfitted with proteins that moves fructose into the cells, and with the right enzyme to create energy from it.

“They have a social structure like insects, they’re cold-blooded like reptiles, and now we found that they use fructose like a plant,” Park says.

No sci-fi alien is as strange as an octopus

Tuesday, May 2nd, 2017

“No sci-fi alien is so startlingly strange” as an octopus, Sy Montgomery noted, but they’re even stranger than we realized:

Rosenthal and Eisenberg found that RNA editing is especially rife in the neurons of cephalopods. They use it to re-code genes that are important for their nervous systems — the genes that, as Rosenthal says, “make a nerve cell a nerve cell.” And only the intelligent coleoid cephalopods — octopuses, squid, and cuttlefish — do so. The relatively dumber nautiluses do not. “Humans don’t have this. Monkeys don’t. Nothing has this except the coleoids,” says Rosenthal.

It’s impossible to say if their prolific use of RNA editing is responsible for their alien intellect, but “that would definitely be my guess,” says Noa Liscovitch-Brauer, a member of Rosenthal’s team who spearheaded the new study. “It makes for a very compelling hypothesis in my eyes.”

[...]

Only about 3 percent of human genes are ever edited in this way, and the changes are usually restricted to the parts of RNA that are cut out and discarded. To the extent that it happens, it doesn’t seem to be adaptive.

In cephalopods, it’s a different story. Back in 2015, Rosenthal and Eisenberg discovered that RNA editing has gone wild in the longfin inshore squid — a foot-long animal that’s commonly used in neuroscience research. While a typical mammal edits its RNA at just a few hundred sites, the squid was making some 57,000 such edits. These changes weren’t happening in discarded sections of RNA, but in the ones that actually go towards building proteins — the so-called coding regions. They were ten times more common in the squid’s neurons than in its other tissues, and they disproportionately affected proteins involved in its nervous system.

Having been surprised by one cephalopod, the team decided to study others. Liscovitch-Brauer focused on the common cuttlefish, common octopus, and two-spot octopus. All of these showed signs of extensive RNA editing with between 80,000 to 130,000 editing sites each. By contrast, the nautilus — a ancient cephalopod known for its hard, spiral shell — only had 1,000 such sites.

This distinction is crucial. The nautiluses belong to the earliest lineage of cephalopods, which diverged from the others between 350 and 480 million years ago. They’ve stayed much the same ever since. They have simple brains and unremarkable behavior, and they leave their RNA largely unedited. Meanwhile, the other cephalopods — the coleoids — came to use RNA editing extensively, and while evolving complex brains and extraordinary behavior. Coincidence?

Liscovitch-Brauer also found that around 1,000 of the edited locations were shared between the coleoid species — far more than the 25 or so sites that are shared between humans and other mammals. These sites have been preserved over hundreds of millions of years of evolution.

No invertebrate on land would have been a match for it

Friday, March 10th, 2017

The earliest tetrapods had much bigger eyes than their fishy forebears, and those bigger eyes evolved before walking legs:

Eyes don’t fossilize, but you can estimate how big they would have been by measuring the eye sockets of a fossilized skull. MacIver and his colleagues, including fossil eye expert Lars Schmitz, did this for the skulls of 59 species — from finned fish to intermediate fishapods to legged tetrapods. They showed that over 12 million years, the group’s eyes nearly tripled in size. Why?

Eyes are expensive organs: it takes a lot of energy to maintain them, and even more so if they’re big. If a fish is paying those costs, the eyes must provide some kind of benefit. It seems intuitive that bigger eyes let you see better or further, but MacIver’s team found otherwise. By simulating the kinds of shallow freshwater environments where their fossil species lived — day to night, clear to murky — they showed that bigger eyes make precious little difference underwater. But once those animals started peeking out above the waterline, everything changed. In the air, a bigger eye can see 10 times further than it could underwater, and scan an area that’s 5 million times bigger.

In the air, it’s also easier for a big eye to pay for itself. A predator with short-range vision has to constantly move about to search the zone immediately in front of its face. But bigger-eyes species could spot prey at a distance, and recoup the energy they would otherwise have spent on foraging. “Long-range vision gives you a free lunch,” says MacIver. “You can just look around, instead of moving to inspect somewhere else.”

Tiktaalik with Eyes Above Surface

Those early hunters would have seen plenty of appetizing prey. Centipedes and millipedes had colonized the land millions of years before, and had never encountered fishapod predators. “I imagine guys like Tiktaalik lurking there like a crocodile, waiting for a giant millipede to walk by, and chomping on it,” says MacIver. “No invertebrate on land would have been a match for it.”

Monarch miscalculation

Tuesday, February 28th, 2017

It looks like a scientific error about butterflies has persisted for more than 40 years:

A few years ago, Christopher Hamm was reading up on monarch butterflies when he noticed something peculiar. All of the scientific articles that mentioned the number of the insect’s chromosomes — 30, it seemed — referenced a 2004 paper, which in turn cited a 1975 paper. But when Hamm, then a postdoc at the University of Kansas in Lawrence, did a genetic analysis of his own, he found that his monarchs only had 28 chromosomes, suggesting that an error has pervaded the literature for more than 40 years. Another twist, however, was just around the corner.

Hamm suspected a mistake when he read the original 1975 paper. The authors, biologists N. Nageswara Rao and A. S. Murty at Andhra University in Visakhapatnam, India, had studied what they claimed was an Indian monarch butterfly in their work. But there’s a problem: Monarchs are nearly exclusively a North American species. “It’s implied they just went outside their building and collected some butterflies,” Hamm says. “I immediately thought, ‘Monarch butterflies in India? Really?’”

Sure monarchs are master travelers, with the longest-known seasonal migration of any insect. And it’s not uncommon for a few to get blown off course to Australia, the Philippines, the United Kingdom, and a handful of other places from time to time. But ending up as far away as India seemed like a stretch. Hamm, now a data scientist at Monsanto in Woodland, California, also knew that taxonomists since Carl Linnaeus have struggled to distinguish species in Lepidoptera, the order of insects to which monarchs belong. For example, the monarch (Danaus plexippus) and a similar-looking butterfly known as the common tiger butterfly (D. genutia) were thought to be the same for more than a century until they were reclassified as separate species in 1954. And guess what: D. genutia lives in India.

Common Tiger Butterfly and Monarch Butterfly

Hamm thinks that Rao and Murty, perhaps not knowing about the reclassification, netted bugs they assumed were monarchs but were actually common tiger butterflies. Back in the lab, they performed a technique known as a chromosome squash — squeezing the butterflies’ cells between thin films of glass until individual chromosomes are visible under a microscope — counted to 30, and published the results. Then, in 2004, Brazilian zoologist Keith Brown Jr. cited the work in his own research exploring the evolutionary history of butterflies; he never suspected that Rao and Murty might have been working with a misidentified species. Brown’s paper has been cited a dozen times since, and the idea that monarchs have 30 chromosomes is now well established in the literature.