On February 22nd, 2018 we learned about

Understanding why so many armored ankylosaurs were found buried on their backs

As jumbled, crunched and scattered fossils make clear, dinosaurs were not buried in an orderly fashion. Bones are often missing, broken or just separated from a body enough to give paleontologists a challenging puzzle to put them back in the same configuration and posture that they had in life. Some of the strange, contorted poses we find skeletons in actually make a lot of sense, such as the bent necks seen on many theropods. In other cases, there’s more of a mystery to be solved, such as why the hulking, armored dinosaurs known as ankylosaurs somehow managed to always get themselves buried upside-down.

The first step to unraveling this mystery to was to confirm if it really existed in the first place. Researchers needed to make sure that a couple of memorable anecdotes about upside-down ankylosaurs hadn’t skewed people’s perception of how common this kind of interment really was. So a short survey of ankylosaur excavations was conducted, looking at both the fossils and field notes concerning 36 different specimens. Sure enough, 26 of those dinosaurs were found laid out on their backs, showing that these animals were unusually likely to be buried upside-down.

Fatal falls

Four hypotheses were developed then tested to see which seemed to be the most plausible explanation for this flipped dinosaurs. Well, they were mostly tested– one suggestion was that these particular dinosaurs were simply unusually clumsy, and did a great job of rolling onto their backs with no way to right themselves. There wasn’t really any evidence to support this idea, and it seemed unlikely that multiple species would have survived as long as they did if something so trivial could lead to their deaths. So option one was essentially discounted from the start.

Pushed by predators

The second hypothesis was that the upside-down ankylosaurs had been flipped by hungry predators. Since their backs were so well protected by bony plates and bumps, called osteoderms, this model suggested that predators could only eat the ankylosaurs’ relatively soft bellies. This kind of activity would presumably be a bit destructive though, and only one specimen out of the 26 was found to have a tooth mark on it. Unless predators were eating ankylosaurs with a very sharp straw, the fossils just didn’t carry signs of damage from other dinosaurs.

Turned over by tummies

If the ankylosaurs were apparently dying peacefully, the focus then looked at the process of decomposition itself. As a body begins to break down, microbes in the stomach can cause it to inflate with gas, leading to bloating in the abdominal cavity. With such a tough, rigid back, a swollen abdomen might push the dead animals off their feet, rolling them over before they were buried and later fossilized. Without any trace fossils of bloated bellies documenting this kind of deformation, researchers looked for analogs in living animals to see if this kind of decomposition was possible in the first place.

While rhinos are large, tough herbivores, they don’t have the right body structure to act as a proxy for ankylosaur death. Instead, researchers looked to armored armadillos, which were said to experience bloating and flipping after they died. Nearly 200 fresh carcasses were located and examined, but none of them were about to roll over as they rotted. A few were even brought to researchers own backyards to make sure they weren’t bothered by scavengers, but their stomachs just didn’t seem to be up to the task of being a post-mortem pneumatic jack.

Whirled in the waves

The final hypothesis involved bloating, but only in a much more mobilized corpse. This model required that the flipped ankylosaur be floating in water, making its top-heavy body much easier to rotate. Armadillos were spared the indignity of being thrown in the water, as researchers tested this idea with computer simulations to see if the weight distribution of various ankylosaur species was at all amenable to rolling over in a lake, river or ocean.

In these simulations, the ankylosaurs finally ended up on their backs. Dinosaurs from the nodosaurid family flipped at the slightest provocation in the water, as even a one-degree rotation could turn them over. Other ankylosaurs, like Ankylosaurus, were a bit less likely to capsize, but some bloating and a good nudge from a wave or predator could still leave them upside-down. What’s more, the sand and silt found at the bottom of many bodies of water would then be excellent material for fossilizing the body once it sank, further increasing the odds that we’d find flipped fossils millions of years later.

Source: Most ankylosaurs were fossilized belly up. Now, scientists think they know why by Matt Warren, Science

On February 22nd, 2018 we learned about

New timeline means that Europe’s earliest painters were Neanderthals, not humans

When the cave of Altamira was first discovered in Spain in 1880, it sparked a controversy over the capabilities of primitive humans. The caves had been essentially sealed for tens of thousands of years, and yet were covered in remarkably sophisticated paintings of people, animals and abstract shapes. Some people found it unthinkable that this kind work could have been accomplished by primitive humans, leading some skeptics to claim the paintings were a hoax. An recent examination of the nearby La Pasiega caves is proving those nay-sayers were half-right, but not for reasons they’d be happy to hear. New research has confirmed that the paintings were not made by early humans, because they must have been created by even earlier Neanderthals instead, 64,000 years ago.

Dated by decay

The paintings in La Pasiega, as well as similar caves found in Maltravieso and Ardales, were originally dated based on the decay of carbon 14 atoms. By measuring the amount of carbon-14 isotopes still found in organic matter and comparing that to the known rate of decay, or half-life, of these atoms, researchers can estimate how old an object is. This method is fairly reliable in some scenarios, but it does have its limitations. In this case, a significant issue is that after 50,000 years, so much carbon-14 has decayed that its hard to detect the remaining isotope in any given sample. Since the La Pasiega paintings are now known to be at least 64,000 years old, it’s easy to see how the previous attempts to arrive at an age ran into problems.

This latest investigation then dated the cave paintings using uranium-thorium dating. Rather than sample the paint directly, this method looks at the amount of uranium and thorium found in the carbonate that has built up over time at a given location. The amount of each product of the uranium’s radioactive decay can then provide an age for that speck of carbonate, which therefore provides the latest possible age of whatever the carbonate is sitting on. So by dating the carbonate that’s naturally accumulated on the paint, we now have a more credible age for the creation of the cave’s artwork.

Advanced cultural capabilities

The technique to date the cave paintings is obviously less surprising than the new estimated age of the paintings themselves. We’re confident that humans didn’t arrive in Spain, or any of Europe, before 40,000 years ago. So with these paintings firmly predating the arrival of Homo sapiens, it seems that our species’ only role in this artwork was discovering it. The only other candidates for their creation are Neanderthals, a species of hominid that seems more sophisticated with every new archaeological discovery we make.

This is a big jump in our understanding of Neanderthals’ cognition and culture. The steps required to develop paint as a tool, pick a location to paint, then represent images of the natural and abstract world represent a variety of achievements. Most importantly, recording images for their symbolic, rather than practical, value shows that Neanderthals were able to transmit their culture in a way we had previously thought to be the invention of humans.

This isn’t to say that humans weren’t culturally innovative. Artifacts estimated to be 70,000-years-old have been found in Africa, showing that Homo sapiens has long been a creative species as well. However, the Spanish cave paintings show that Neanderthals weren’t trailing far behind our species in their development. Researchers now want to investigate other European cave paintings in case they were made by Neanderthal hands as well.

My five-year-old asked: How did they make their paints?

The caves were only painted in reds and blacks. The black was from charcoal, most likely retrieved from a fire, and the red was made of pigments like ochre. The painters probably started by crushing the minerals into a fine powder, then moistening them with water or oil to make them spreadable on the stone walls of the cave.

Source: Neanderthals were artistic like modern humans, study indicates by Andrew White, Phys.org

On February 21st, 2018 we learned about

The sounds of snapping shrimp used by scientists, and whales, to estimate the abundance of coastal wildlife

Your alarm clock may play soft, soothing sounds of distant waves to help you nod off to sleep, but you’re only getting a tiny portion of the cacophony of noise echoing through the ocean. From whale greetings to acoustic gravity waves, there are a lot of vibrations moving through the water. Researchers are learning to listen in more carefully, as these sounds are a great way to monitor what’s happening in underwater ecosystems, although they may be a bit late to the party. Some studies are finding that the residents of the ocean, like Pacific gray whales, may regularly be tuning into specific sounds as indirect indicators of where to find a bite to eat.

Popping as a population proxy

One of the louder sea creatures capturing human and cetacean ears is the snapping shrimp. Like its infamous cousin, the mantis shrimp, this crustacean can snap its claw shut so quickly that it causes a tiny, temporary vacuum in the water, called a cavitation bubble. That bubble then collapses, releasing a lot of energy in the process, hopefully stunning the shrimp’s prey so it can capture its dinner. Like less dramatic bubbles, the bubbles also make a loud popping noise that can be heard from a considerable distance away.

When enough snapping shrimps are hunting at once, these pops start to sound like a bit like something sizzling and splattering in hot oil. Because it’s coming from groups of shrimp hunting at once, researchers have started using the sound to estimate shrimp populations and activity levels. For instance, summer waters off the coast of North Carolina see a 15 decibel increase, as shrimp crackle and pop up to 2,000 times a minute. In the winter, they calm down considerably, with no more than 100 pops being recorded in a minute.

Signaling snack time

Snapping shrimp surprised researchers off the coast of Oregon when they dipped a hydrophone into the water. The shrimp were previously unknown in the area, and yet they were clearly turning up in sizable numbers in researchers’ recordings. What’s more, the researchers apparently weren’t the only one’s listening for snapping shrimp, as Pacific gray whales often turned up when the shrimp started hunting.

The whales weren’t following the popping sounds to eat the shrimp though, as the noisy crustaceans just aren’t part of their diet. The best guess at this point is that the whales understood that the shrimp’s activity meant there was other food nearby. Since so much of the ocean is essentially devoid of food, following the sound of the popping bubbles saves the whales a lot of trouble. They’ve learned that when the shrimp are hunting, there’s probably something for whales to eat in the same location. With whales’ keen sense of hearing, the noisy bubbles must be hard to ignore.

Like those whales, ecologists are looking to figure out just how reliable a signal the snapping shrimp can be. If they’re consistent enough, listening for the sound of shrimp bubbles may be a relatively quick and inexpensive way to assess the health of coastal ecosystems, and maybe find some hungry whales at the same time.

Source: Snapping Shrimp May Act as 'Dinner Bell' For Gray Whales Off Oregon Coast, AGU.org

On February 21st, 2018 we learned about

Tsunamis may soon be detected with a single hydrophone and a decent amount of math

Tsunamis aren’t subtle, but they do still manage to be surprising. They’re created by earthquakes under the sea, sometimes so far from a coast that people will have no idea any seismic activity occurred. Then, once the surge of water reaches a shoreline, anyone there has very little time to react and escape the area. As we get better at monitoring the ocean floor for earthquakes, these events are becoming slightly easier to predict, but the sea floor is so vast that it’s not the most practical endeavor. However, new research is suggesting that the key to catching tsunamis earlier may come down to listening to the sea, and acoustic gravity waves in particular, in just the right way.

Massive amounts of movement

When an earthquake occurs in the ocean, there’s obviously a lot of shaking and vibrating going on. In addition to massive amounts of displaced water, a quake will send out acoustic gravity waves (AGWs) in every direction. These waves are a bit like a hybrid of sound waves moving laterally through the air, and the gravity-sensitive waves you see shaping fluids like the average waves near a beach. This has made AGWs tricky to study and model, since they don’t follow the exact patterns we see in more common wave activity. One trait that has stood out, however, is that an AGW can move through the ocean at the speed of sound across huge distances. Because of their impressive sizes and speeds, researchers have long hoped that they could be detected well in advance of a tsunami’s arrival, buying people more time to get to safety.

The difficulty hasn’t been detecting the AGWs, but making sense of them. Fortunately, scientists from the University of Cardiff are now suggesting that this kind of analysis is not only possible, but practical even with only a single hydrophone sensor in the ocean to detect the wave. The distinct shape and speed of any AGW should reveal various aspects about the earthquake that created them. With more information in the system, such as details about the suspected fault location, researchers state that the tsunami’s amplitude and potential impact on a shoreline can be predicted. Once compiled, these data could then be used to trigger tsunami alarms in the tsunami’s path, giving people crucial time to find safety.

Heard through single hydrophone

On a basic level, this is similar to the tsunami alarms we have today. Devices known as dart buoys are anchored at sea, and can then detect unusual pressure changes in the water below them. This works if the buoys are in the tsunami’s path, which then requires that they’re located in all the right locations at all the right times. Measuring AGWs, however, don’t require that kind of specific placement. Because AGWs expand in multiple directions from an earthquake’s epicenter, hydrophones in any direction could detect clues about the formation of a tsunami. This then leads to a much more practical system for early warnings, increasing the chances that an alarm will reach people with enough time to get away from the water.

Source: Could underwater sound waves be the key to early tsunami warnings? by Cardiff University, Science Daily

On February 19th, 2018 we learned about

Bat feces is a crucial fertilizer for Cambodian farmers

Even though nobody can grow or eat it, bat poop has become one of the most lucrative markets in Cambodian agriculture. Farmers have long encouraged bats to roost in the palm trees near their fields so that they could ‘harvest’ the guano that accumulates on the ground to use as fertilizer. In many cases, they will even tie extra palm fronds to trees in order to make them denser and more accommodating to the flying mammals. The effort is worth it, as bat poop is in such demand that guano-cultivators don’t even need to haul it to markets- clients will come to them, then buy the poop for around 38 cents a pound. That may not seem like much, but earning up to $10 a day for maintaining a bat latrine is attractive enough for some farmers to drop their other crops and focus on guano exclusively.

Fantastic feces for farmers

The idea that poop makes a good fertilizer isn’t new. Horse manure, bird poop and bat poop have all been used as a source of nutrients for plants around the world. In Cambodia, part of particular attraction to bat guano is just how well it performs. Controlled experiments have found that crops like eggplant, jackfruit and longan fare better with bat poo than commercial fertilizers, even though the feces has less nitrogen, phosphorus and potassium per pound. The magic of the bat droppings hasn’t been conclusively proven, but it’s thought that the other materials commonly found in bat poop, right down to beneficial bacteria, likely plays a role. The fact that the guano also helps with things like water retention in the soil makes it even more attractive, as farmers feel like the poo just makes for higher quality crops and soil.

In the case of certain crops, the bat poop is actually required. Heritage crops like the Kampot pepper are not allowed to be grown with industrial products like commercial fertilizers, as per the Kampot Pepper Promotion Association. Bat guano, having been a part of Cambodia’s ecosystems long before people were farming there, is allowable, driving those farmers to stock  up on bat droppings every year.

Bats versus bug spray

While bat feces are clearly a winner against other fertilizers, there’s growing conflict with farmers’ use of pesticides. While insect-eating bats are saving rice farmers as much as $300,000 per year in pesticide purchases, enough of the poisons are being used in Cambodia to pose health risks to the bats. While the rapid reproductive rates of insects give them a chance to develop resistances to pesticides, bats aren’t keeping up as well, and their populations are being hurt by the increasingly strong doses of poisons being used around farms. That then leads to fewer bats to hunt the insects and fewer bats to make new fertilizer.

It seems like the bats present a win-win for farmers, but conservationists are still concerned about their well-being. Farmers exposed to advertising for commercial fertilizers and pesticides were less likely to rely on bats, meaning the guano-harvesters may need to start investing in bat guano’s branding to make sure it’s properly appreciated in the public eye.

Source: Bat faeces: how this ‘black gold’ improves the fortunes of Cambodian farmers by Claire Baker-Munton, Southeast Asia Globe

On February 19th, 2018 we learned about

A runny nose’s excessive boogers are made in our body’s best interest

It’s only been three days since my son’s nose started getting snotty, but that’s long enough to make you wonder why, and how, all this mucus keeps coming out of his nose. At just shy of five-years-old, he’s technically able to handle a tissue himself, but not to the point where he can be expected to be effective in his booger management. Coupled with the sore throat and cough of a nasty cold virus, all this mucus-production feels like a bit of a curse. Of course, it’snot— it’s simply our body’s way of purging pathogens that are trying to take up residence in our respiratory tract.

On any given day, your sinuses are doing double-duty at a minimum. They warm and moisten air before it gets to the sensitive tissue in our lungs, plus captures junk that we don’t really want to be inhaling in the first place. That can be dust, dirt, pollen and of course, viruses and bacteria. Ideally, the layer of mucus that coats the inside of your nose and sinuses is enough to capture these potential irritants, moving the sticky stuff back down your throat with hair-like structures called cilia.

Purging pathogens

As my son’s clogged nose can attest, sometimes things get through. There’s likely to be some resistance in your mucus from benign bacteria, but your immune system revs up when a pathogen start penetrating cell walls in your nose. Proteins called cytokines are released, which then activate T and B cells that will attack the pathogen directly. To help in that battle, the lining of your nose swells and increases its booger production, hopefully creating enough mucus to grab and flush the offending pathogens out of your body. Unless of course you’re five, in which case you’ll probably get the contaminated snot on your hands and spread it far and wide, infecting everyone around you. (Not that we hold that against you, son!)

From the outside, this all looks like a runny nose. The excess fluid in the swollen mucus lining can lead to gross, drippy discharge in a condition known as rhinorrhea. Sometimes the extra mucus just clogs things up, making us feel horribly congested in the process. You can blow your nose to help with that, but violently trying to force the boogers out of your face can actually damage the cilia that help move mucus around. It can also end up sending pathogens deeper into your sinuses, kicking of new infections. So even though a drippy nose is annoying, it’s actually working as intended.

External influences

Of course, sometimes your nose is drippy when it doesn’t need to be. For instance, cold weather can trigger a runny nose in healthy people, albeit for very different reasons than described above. In those cases, the air is probably cold and dry enough to make your mucus linings activate in an effort to keep air properly warmed and moistened on its trip to the lungs. That can lead to extra fluid in your nose that then starts dripping out. Alternatively, there’s a chance that moisture in the air is condensing just inside your nose, forming noticeably large droplets that feel like snot.

Finally, crying can lead to a runny nose because eyes are just filling the place with fluid. As tears drain into your nose, they soften the layer of mucus that’s always present enough to start flowing. That way, your emotional moment can feel a bit sticky too.

My third grader asked: Is the runny nose you get from cold air the reason we call it a ‘cold?’

Basically. A “cold” was first used to describe illness in the 1530s, long before anyone knew to look for the rhinovirus or coronavirus that was actually causing a person’s symptoms. The resulting infection felt enough like the unpleasant effects of being chilled that it easily described what was wrong with someone, even if it did lead to confusion about what actually causes the illness (mostly.)

Source: Why Does Your Nose Run When You’re Sick? by Alexandra Ossola, Popular Science

On February 18th, 2018 we learned about

Mulan versus history: women who assumed male identities to join the military

When watching a cartoon like Disney’s Mulan, my kids are fairly confident that things like the ancestors’ spirits, talking dragon and lucky cricket never really happened. When I press further, they’re hesitant about the rest of the story too. Movies are, by default, fiction in the eyes of my eight- and four-year-old, so why would Mulan be any different? As it turns out they’re both right and wrong about this— as far as anyone can prove, Fa Mulan never existed outside of folklore. However, the core premise of a woman disguising herself as a man to fight in the army seems to have been repeated in history often enough to make the story very easy to believe.

Disney didn’t invent the story of Mulan, although their version is definitely different from how she’s been represented in Chinese ballads and storytelling. Every version starts with the idea that Mulan wants to take her father’s place in the Chinese emperor’s army, the context and reactions to that choice diverge immediately. Whereas the Disney cartoon is based around a teenager who feels like she doesn’t fit society’s image of a woman secretly donning her father’s armor, a Ming Dynasty ballad by Xu Wei called The Female Mulan Joins the Army in Place of her Father is based around a girl who is comfortable with the idea of staying at home and sewing, but was also explicitly trained by her father to be a fighter as she grew up. She hides her sex from the army when she joins, but convinces her parents that her enlistment is the only sensible option for the family if they want to fulfill their duties to the emperor. She does unbind her feet to make this transition, but while planning to rebind them once she returns home. It’s a very different approach to gender roles than a modern audience might expect.

Incentives for enlistment

Of course, gender expectations have long been rigid enough to block women from enlisting under their own identities for most of recorded history. Even without a real Mulan to point to, many other women have fought under assumed male identities, usually to stay closer to a brother or husband, escape an abusive family, earn more money than a woman would otherwise have access to or, as in the Chinese ballad, fulfill a sense of duty and patriotism.

Elisa Servenius dressed as a Swedish man to fight in the Finnish War of 1808 in order to remain close to her husband, who was also a soldier. He went missing in 1809, but Servenius continued to serve, partially so that she could try to find her lost spouse. Having been captured, Mr. Servenius was released in 1810, and the two were reunited.

Sarah Malinda Pritchard Blalock signed up with the American Confederate Army to follow in her husband’s footsteps towards defecting to the Union Army. William Blalock purposely enlisted in a company he figured would be sent to the Virginia border so that he could flee north more easily. He didn’t realize that his wife, after cutting her hair and adopting the name Sam, would attempt the same strategy. It didn’t work for either Blalock as intended, and both had to simply flee north after getting medical discharges. In the end, they both joined the Union Army, fighting in raids in the Appalachian Mountains.

In a reversal from Mulan’s reverence for her father, Sarah Emma Edmonson joined the Union Army in 1861 to avoid her father. She’d fled her native Canada in 1857, starting a new life first as Sarah Edmonds, then later as Franklin Thompson. As “Thompson,” Edmonds enlisted and took on a number of roles in the war, from hospital attendant to spy to battlefield courier. While she managed to survive a broken leg and other injuries, she felt the need to desert the army when she came down with malaria, lest her disguise be revealed while hospitalized.

Earning, and claiming, income

Edmonds’ desertion raises the issue of how secretive these women had to be, and what the consequences were once their sex was found out. From the records we have, Disney actually suggested more severe penalties than anyone actually faced. Their version of Mulan feared not only the disapproval of her parents, but also execution by the state of the army discovered that she was a woman. Even the Ming Dynasty version has Mulan’s friends immediate embrace her identity once she reveals a 12-year deception, and nobody in the story worries about an execution in the slightest. While not every woman was able to leave the armed services on quite so favorable terms, multiple women did manage to receive pensions for their status as veterans.

In Edmonds’ case, her desertion did work to preserve her secret identity. Once she recovered, she worked as a nurse, but also wrote about her time in the Union Army. She even managed to get her alter-ego’s desertion charges cleared in order to claim her pension in 1884.

Mary Lacy posed as a 19 year-old-boy named “William Chandler” to join the British Navy in 1759. She was a successful sailor and shipwright, at least until rheumatism force her to stop working in 1771. Still, she did manage to not only earn a pension, but also receive it under her original identity, Mary Lacy.

Jennie Hodgers adopted the name Albert Cashier to fight in the American Civil War. She managed to keep her identity secret not only throughout the war, but even afterwards, as she chose to keep her male identity for the rest of her life. Not only did she receive the pension she earned under her new name, but also lived in a soldiers’ rest home in Illinois. The staff there did eventually discover her secret, but they never disrupted her life by making it public.

Consequences when caught

Not every woman managed to control their identity this well though. As in Disney’s Mulan, injury and illness that required medical treatment would, understandably, expose people’s secrets. Some were temporarily detained (sometimes to be guarded by another woman posing as a man!) while others were just sent home. In the case of Dorothy Lawrence, the British Army was more concerned with how easily she’d faked her way to the front lines of World War I. After confirming that she wasn’t a spy, the biggest concern was to make sure her story didn’t get out and embarrass the Army, or encourage more women would attempt the same feat Lawrence had. Luckily for the top brass, the multiple versions of Mulan weren’t in wide circulation at in England at the time.

Source: Mulan vs. The Legend of Hua Mulan, Disneyfied, or Disney Tried?

On February 15th, 2018 we learned about

Fossil footprints suggest that lizards have long been able to run on only two legs

110 million years ago, a small lizard near the coast of what is now South Korea was being pursued by a pterosaur. To better evade the predator’s attack, the lizard appears to have reared up, sprinting on its back legs across the moist sand. This upright-sprinting not only gave the lizard a boost in speed, but probably helped the lizard’s maneuverability, making it that much harder for the pterosaur to catch.

My third grader asked: Wait, the lizard ran upright? Like a human?!

Well, not exactly like a human, as lizards’ legs are angled out to the sides of their bodies, rather than under them. Looking at the 50 species of living lizards that can also pull off this maneuver, they don’t look a whole lot like humans as they run. In some cases it’s almost supernatural looking, as when the basilisk or “Jesus Lizard” (Basiliscus basiliscus) sprints across the surface of water.

My third grader said: Oh, like Dash from The Incredibles.

Ok, they’re not quite that fast, but the lizards that run on their hind legs today to move pretty quickly. That speed may even help explain how they started running this way to begin with— one hypothesis is that as a lizard with smaller front legs picks up speed, their center of gravity effectively moves back to their hips. They can then tip up over their hips, making turning easier compared to running on all four legs. However, that uses a lot of energy for a cold-blooded animal, which is probably why they’d save it for critical moments instead of becoming bipedal all the time.

Scientists aren’t actually sure how, or when, this behavior got started. Small lizards don’t get fossilized as often as bigger animals, so we don’t have tons of examples of every intermediate form that would hint at changes in the reptiles’ gait. Fossilized footprints aren’t common either, and these particular tracks aren’t only the first record of a bipedal lizard’s movement, but of any lizard at all.

My four-year-old asked: How are they sure the tracks are from the back feet only?

The tracks are clear enough to preserve specific details about the feet that made them, right down to toe and claw placement. There are a couple of prints that appear to be from the lizard’s front feet towards one end of the trackway, which help contrast from the back feet as well, particularly in their size. Combined with the distance between each foot, it all matches what might be expected when a small lizard was making a quick dash on its back legs.

Of course, it’s hard to be absolutely certain about something like a footprint. There is always a chance that the lizard was walking on all four limbs, but that the smaller front legs just weren’t making impressions in the soil. There’s not a lot to suggest that that’s the case, but it’s good to keep in mind that footprints alone aren’t giving us the whole story.

My third grader asked: So are we sure it was a lizard? How do they know it was being chased by a pterosaur?

The feet do match the anatomy of a lizard, and there’s no doubt that this type of animal was alive 110 million years ago. What motivated this particular critter to take off running is much more speculative— Yuong-Nam Lee, the paleontologist who discovered the tracks, was originally searching in those rocks for pterosaur prints. At first, he barely paid attention to the lizard prints once he realized they weren’t from a pterosaur. So while pterosaurs likely lived in the vicinity of the sprinting lizard at some point, there’s no direct evidence that these tracks were made to avoid being eaten.

Source: Lizards ran bipedally 110 million years ago by Hang-Jae Lee, Yuong-Nam Lee, Anthony R. Fiorillo & Junchang Lü, Nature

On February 14th, 2018 we learned about

Magpies’ mental capabilities may stem from the size of their social circle

As a brain-heavy species, it can be hard for humans to imagine how more brains aren’t always the best option for an animal’s evolution. After all, without our cognitive abilities, how could we synthesize medicines, build rockets, and argue on social media all day? Oddly enough, as stupid as the “discussions” on social media can feel sometimes, they may be a part of what drives cognitive development in the long run. A study of highly social birds has found a correlation between social interactions, intelligence and even reproductive success. At least for Australian magpies, a bigger social group seems to be tied to better problem solving and a fitter family.

Like other crows, ravens other notably-brainy birds, Australian magpies (Gymnorhina tibicen) are very social animals with excellent memories. In the course of their 25- to 30-year life spans, they can build lifelong bonds with their social groups, which can vary anywhere from three to 12 birds in a flock. Like crows, they’ve even been known to learn the faces of specific humans, remembering how those humans treated them in the past to interact more appropriately in the future. This alone seems like a benefit of their intelligence, but clearly that intelligence has been developing before the birds had to react to humans on a daily basis. It’s been hypothesized that needing to understand and interact with their fellow magpies may have been enough to push the birds’ brain development.

Better brains from bigger groups

To test the connection between a magpie’s social group and problem solving skills, researchers tested individual wild birds with different sorts of tasks, generally designed around gaining access to some food. The birds were different ages, but all generally younger to reduce the chance that they would have prior experience with these tasks. The challenges consisted of things like retrieving food from a clear tube, requiring the bird stop approaching it directly from the side of the tube, and muster the self-control to go after it from the ends where an opening was. Another task required that the birds remember a specific color cue over time to earn a food reward.

In each case, birds that lived with larger social groups performed better than those that lived in smaller groups. That alone doesn’t really explain the origin of the birds’ intelligence though, as it doesn’t demonstrate that one attribute lead to the other. However, researchers also found that the more successful female magpies tended to have more offspring than their more befuddled peers. Since the average magpie only has a 14 percent chance of successfully breeding, even a small reproductive advantage would be important. While this doesn’t specify how problem solving or living in a large group directly benefits reproduction, there’s a least a model for how these traits would be propagating in the magpie population.

My third-grader asked: What if the bigger groups just have more teamwork to solve problems? Or what if they can share more information with each other?

By working with juvenile birds, they hopefully had to approach their food-finding tasks without prior knowledge of how to solve them. With that said, magpies have been observed watching and apparently learning from each other’s behavior, so the idea that these birds are sharing knowledge as some kind of culture can’t be written off entirely.

Source: Large-group living boosts magpie intelligence by University of Exeter, Science Daily

On February 14th, 2018 we learned about

TRAPPIST-1 planets orbits suggest they’re soaked in substantial amounts of water

In 2016, astronomers located a batch of presumably rocky exoplanets orbiting TRAPPIST-1, a red dwarf star 40 light years from Earth. While red dwarf stars are generally cooler than our own Sun, some of these planets have tight enough orbits to put them in habitable temperature ranges for life, assuming that life was happy living under a dim red sky. Continuing observations of the TRAPPIST-1 system has revealed more details about these worlds, including the likelihood of vast amounts of liquid water on their rocky surfaces.

Calculating exoplanet composition

At 40 light years away, astronomers aren’t observing signs of water or ice directly. Instead, they’re taking measurements of planets TRAPPIST-1b through TRAPPIST-1h and comparing how they interact with each other’s orbits. Like all matter, each planet creates its own gravitational field that pulls on its neighbors. While they’re not overpowering the pull of their star, researchers have been able to detect small wobbles in the tight orbits of each planet when they move near each other, allowing them to come up with estimates for how massive each planet might be. That information is then compared to estimates for the planets’ volumes, a figure based on how much light each planet blocks when passing in front of the TRAPPIST-1 star. To verify these estimates, researchers then plugged them into simulations of the system, making adjustments until their virtual orbits matched observed data.

Once each planet’s mass and volume were known, researchers calculated their density. The resulting picture of each planet’s composition isn’t inert pieces of rock, but worlds with large amounts of “volatile,” or more dynamic, materials on their surface. Based on the planets’ close proximity to their star, there’s a good chance that this volatile material is some form of water thanks to that molecule’s abundance in the materials that eventually go on to form planets. What’s more, there’s a good possibly that this water exists as a liquid under a thick, steamy atmosphere. Before you picture a second Earth under a reddish sky, planets like TRAPPIST-1b and TRAPPIST-1c may actually make our own planet look dry, as they’ve been estimated to be made of up to five percent water, versus Earth’s 0.02 percent.

Home to water, but without being wet

Not every TRAPPIST-1 planet is expected to be wet, spherical sauna though. TRAPPIST-1d is the smallest of the group, and may have a layer of ice on its surface. TRAPPIST-1e is a little denser than Earth, probably thanks to a more substantial iron core. It likely lacks a considerable atmosphere, with rockier composition overall. Further out, TRAPPIST-1f, g and h are probably too far from their star to maintain a large amount of liquid water, much less vapor. Any water they have would be frozen, and there’s no sign of a substantial atmosphere at this point.

Is there water around every red dwarf?

While there’s more to be learned about the TRAPPIST-1 system, researchers would also like to start using these simulations and analytical techniques on other red dwarf solar systems. It seems that not every star needs to be yellow-hot to be home to some very attractive-looking planets, but it would be great to know just how common these sorts of water-soaked spheres really are.

Source: TRAPPIST-1 planets probably rich in water by ESO, Science Daily