On October 6th, 2015 we learned about

Dinosaur biographies revealed through survey of shin bones

Paleontologists can tell a lot from a single bone. An identifiable piece of a skeleton can be used to estimate the overall size of the animal. Single teeth have been used to name new species. These bones can help describe the shape and size of an animal, but can’t say as much about how that animal lived, because comparing one species to another will likely introduce too many other variables to know what caused what. However, when that single bone has been found from 50 individual specimens of the same species, a very different kind of analysis becomes possible.

A bone bed in Montana has yielded a vast collection of Maiasaura peeblesorum skeletons from the late Cretaceous. Maiasuara were large, plant-eating hadrosaurs, growing up to 30 feet long. They famously lived in groups, tending to young in their nests much like some modern birds’ nesting colonies. Aside from earning the name “good mother lizard,” this communal care-taking led to the multi-generational group at the center of this study. Scientists compared the tibiae, or shin bones, of 50 specimens to see just what it meant to be a young or old Maiasuara, focusing on the growth patterns within each fossil.

Lives lived in less than a decade

These hadrosaurs weren’t living long, luxurious lives. Most of the young died by the time they were one year old. At that age they were more likely to walk on only their hind legs, and their clustering in nests indicate that they needed a lot of care. By age three, the surviving youngsters were sexually mature. The adults seemed to live fairly peacefully, growing up to 2.3 tons, and eventually living more of their life on all fours. By age eight, they were over the hill already, with signs of increased mortality. This growth curve may seem short and steep when compared to large modern animals, like a 50-year-old African elephant. Researchers instead compared their maturation to modern birds, who have a similar rate of growth.

The story told by shins

This look at shin bones is based around the idea that each Maiasuara‘s health and lifestyle would shape their growth, and that that growth would then be recorded in their bone structure, almost like rings in a tree trunk. Aside from the biographies of each specimen, the variations seen in the shins indicated that we might need to couch our size estimates when discovering other fossils. The size of a bone has often been used to determine the size and/or age of a specimen, but the variety in these 50 animals shows that that’s not a reliable metric. As more skeletons of Maiasuara are examined, there is hope that we’ll be able to further understand not just the range of sizes and shapes of these dinosaurs, but more about their lifestyle as well.

Source: Largest dinosaur population growth study ever shows how Maiasaura lived and died by MSU News Service, MSU News

On October 6th, 2015 we learned about

British bones bear badge of Bronze Age mummification

Identifying a mummy should be pretty cut and dry, right? Preserved bodies, sealed in pyramids, surrounded by gifts for the afterlife, case closed? We’ve actually known for some time that ancient Egypt was not the only culture to mummify their dead, and new research techniques may be about to expand that list significantly. The latest addition came from as far from a desert pyramid as you could imagine, having been exhumed from a bog in England.

One of the advantages of preserving the dead in a desert is the dry conditions should help slow the body’s decomposition. However, swampy conditions can help preserve a corpse as well, thanks to the fine sediment sealing the body away from disturbances and savaging organisms (which has also helped create a lot of fossils we find today). The body wasn’t really comparable to an Egyptian pharaoh though, as the flesh wasn’t still present. Fortunately, even the remaining bones can tell the story of the earlier mummification.

Bones without (major) bioerosion

Microscopic analysis of the bones were looking for signs of putrefactive bioerosion. Most bones have plenty of evidence of decomposition, unless they’ve been preserved in some way. Once the newly discovered bones were examined, they were compared to known mummies from Ireland and Yemen. Since they had similar patterns of bioerosion, it seems safe to say that the skeleton from Bronze Age England had be preserved after death, possibly from techniques like organ removal or even smoking over a fire.

This new technique for examining bones is likely to change our conception of the practice of mummification and burial rituals. Other bodies from Bronze Age England have shown signs of preservative efforts, but this microscopic analysis technique opens the door to finding mummification in the story of many more skeletons. It’s possible that these burial rituals were much more widespread than we’d even thought to look for, in England and beyond.

Source: Mummification was commonplace in Bronze Age Britain by University of Sheffield, Phys.org

On October 5th, 2015 we learned about

The fierce but faint roars of mirid bugs

You’ve probably never heard of Macrolophus pygmaeus or Macrolophus costalis, but more importantly, you’ve never heard them either. They’ve been found to produce some impressive sounds, comparable to a lion’s roar, but since they’re not normally audible to human ears we’ve been missing some amazing exchanges between these small insectivores. While we’ve now figured out how to listen in, the next step is to figure out how they’re even making these tiny roars in the first place.

Both species are mirid bugs, which live around the world eating things like aphids and whitefly. They save their auditory ferocity for their peers though, with males roaring when a second male turned up on the first male’s leaf. The defending male’s roar almost always elicited a response from the new arrival, suggesting that the two were shouting each other down for either territorial or possibly mating dominance.

Listening with lasers

While recordings of the roars sound impressively like big cat when amplified, “roar” may be a touch misleading. There’s no hint these insects are opening their mouths to emote, as the sound is actually produced by vibrating the leaf beneath their feet. The sound produced includes a variety of frequencies, helping it carry through the various materials that make up the plant they’re standing on. As such, they’ve only been recorded by placing laser vibrometers on the leaves themselves to pick up the vibrations the bugs are somehow creating.

Source of the sound

There’s still some questions about how they’re doing that. Despite the dramatic output of a bug-scaled roar, there’s no obvious action creating the sound. Unlike a cricket that can clearly be observed rubbing their ridged wings together to produce their distinctive chirps, the mirid bugs sound off without any unusual movements. The one clue is that they seem to need to be in motion to make the sound, but what piece of anatomy is otherwise vibrating has yet to be determined.

Source: Zoologger: The tiny insects that roar at each other like lions by Robin Wylie, New Scientist

On October 5th, 2015 we learned about

The mishmash of meanings we’ve manufactured for “vegetables”

I’m probably going to regret sharing this with my kids, but… vegetables are a bit of a lie. Obviously carrots, potatoes, and broccoli are all real plants, but the idea that a “vegetable” is actually something more specific than “foods my kids will whine about” isn’t really true. The word itself originally just referred to plant life. It wasn’t until the 1700s that it took on the now common meaning of “plants we eat.”

Botanically bankrupt

Compared to fruit being structures meant to carry a plant’s seeds, the idea of a vegetable has sort of been mushed into a catch all for “everything else.” From a botanical perspective, there’s no real relationship between carrots, lettuce, onions or mushrooms. As a root, leaf, bulb and a fungus-that’s-not-even-a-plant, it’s clear that the ingredients of a vegetable soup are there because of our taste preferences more than anything else. But even with that degree of flexibility, the categorization of different edible plants has been stretched to a degree where you might be tempted to define “vegetables” simply along the lines of “I know one when I see one.”

Legal logic

In 1883, the Tariff Act in the United States was raising prices on imported vegetables, but not fruit. It would seem that this distinction would be pretty cut and dry, thanks to tomatoes carrying seeds and thus clearly being fruits. The Supreme Court disagreed though, basically saying the common usage of tomatoes as vegetables in most cooking trumped stricter definitions, and that the tariff could be imposed. The European Union has gone the other way, ruling that rhubarb, carrots and sweet potatoes are all fruit, at least if they’re being used in jams.

These legal rulings can matter to more than just tariffs though. In regulating the nutritional standards for school lunches, Congress has waded into the murky waters of defining vegetables, far beyond concerns over seeds, roots or leaves. In the 1980s, changes were made that would effectively allow ketchup to be counted as a serving of vegetables because of the tomato content, (probably not thanks to the onion powder.) Going further with this idea, in 2011 Congress allowed reduced portions of tomato paste to count as a serving of vegetables, which effectively allowed pizza to be the equivalent of a serving of carrots (or any other non-fruit flora.)


 

My first grader said: Well, since kids this age have the instinct of a lawyer looking to follow the letter but not the spirit of a law, we immediately had to discuss a new label for our requests that she eat her… plants. “Greens” was out for being too narrow, “non-fruit plants” brought up the whole tomato problem again, and we obviously had to avoid suggestions like “things that are yucky.”

For now we’re going with the pleasant notion of eating a “whole rainbow” of foods to push some variety, although I’m curious to see how much eggplant or grapes she’s willing to eat to cover her purple obligations.

Source: Do vegetables really exist? by Henry Nicholls, BBC Earth

On October 4th, 2015 we learned about

Chameleons climb with consolidated but complex toes

Opposable thumbs are, ahem, very handy for grabbing things. Humans have obviously made great use of our hands, and other animals like orangutans rely on their digits so much, they still have them on all four limbs. Tree-borne chameleons seem to be in the process of taking this concept to the next level, as their feet more or less resemble two thumbs that they can use to clamp onto sticks and branches. Oddly, as they consolidate the number of digits on their hands and feet, they’re simultaneously increasing the number of bones in their bodies.

The structure of the chameleon’s two-toed foot is hinted at by the small array of claws on one of the toes. One “toe” is comprised of two digits, and the other is made of the remaining three fingers, fused by muscles and tendons, sort of like a mitten when you misalign your fingers. More primitive, grass-dwelling chameleons don’t have these fused digits, suggesting that this is an evolutionary recent adaptation to life in the trees. The consolidation allows arboreal chameleons, like the veiled chameleon (Chamaeleo calyptratus), to move more quickly and nimbly along narrow branches.

Flexible over firm

It would make sense to assume that over time these fused-digits will become one appendage, saving the chameleon the trouble of growing the extra bones. However, observations of chameleon growth shows that their bodies are working in the opposite direction. Embryos were found to have extra wrist and ankle bones, so that do eventually fuse, leading to more flexible ball-and-socket joints for the feet. A series of small bones allows for better flexibility and grip compared to fewer, larger bones, so the reptiles might not be in a hurry to simplify their toes too much.

Source: Why Some Chameleons Are Expert Tree Climbers by Charles Q. Choi, Live Science

On October 4th, 2015 we learned about

How wildlife holds out during a hurricane

One of the problems with natural disasters like a hurricane is that they can turn any and all of your surroundings into a potential threat. Even a home can be stripped, shaken and flooded, transforming it from a haven to a hazard. This is true for animals as well as humans. Even though a fish or a rabbit isn’t worried about something like their windows breaking, they still face many of the same dangers humans do, from the destruction of their homes to a lack of accessible food once the storm is over.

Out at sea, fish don’t worry about their home being “broken” per se, but that doesn’t mean they’re out of danger when a hurricane comes to their patch of ocean. The strong winds of a storm and disrupted currents can mix and move warm and cold water, leaving fish in an environment they’re ill suited to until things settle. These strong currents and winds can also move the animals entirely, leaving them beached in a worst case scenario. In shallower areas, the violent waves and swirling debris can also destroy coral, leaving ecosystems in disarray for years.

On land, the question becomes flooding. Animals in surviving trees have a decent chance of using the tree as shelter, assuming the winds don’t destroy the tree. Riding the storm out along the ground is harder. Burrowing animals are especially at risk from flooding and falling debris. Once things dry out, the winds often disrupt food chains, stripping plants of valued seeds, fruits and leaves that would have normally been an herbivore’s lunch.

Some silver linings

A hurricane doesn’t have to be the end of the world though. Sharks seem to sense shifts in barometric pressure, and have been known to vacate regions where a hurricane is approaching. Some animals caught in storms can ride them out, and have even been transported huge distances on natural rafts, only to do quite well in their new environment. Animals who remain at the site of the hurricane may face a temporary loss of food sources, but similar to the regrowth after a forest fire, new plants can often take advantage of freshly cleared land, inviting larger and larger species to return.

Source: What happens to animals in a hurricane? by Sarah Zielinski, Wild Things

On October 1st, 2015 we learned about

The multi-faceted misfortunes of the Mesozoic’s mass extinction

66 million years ago, the dinosaurs went out with a bang. And apparently some rumbling. And explosions. And drowning, and poisoning, and eventual starvation. But not firestorms, at least, as those have been mostly ruled out. While it may seem like these ancient creatures had everything but the kitchen sink thrown at them, it appears that the extinction of non-avian dinosaurs was the result of a trifecta of problems: a dip in biodiversity, an asteroid or comet strike, and then up to 500,000 years of volcanic eruptions.

Susceptible species

The first concern is probably the least flashy. Steve Brusatte of Edinburgh University is looking at the idea that dinosaurs were suffering from a lack of biodiversity around 66 million years ago, right before the famous extinction event. On it’s own, this wouldn’t really matter, but homogeneous populations are potentially more fragile than those with a wider array of speciation. Shifts in the food web may not favor the dominant species, but others might not be ready to pick up the slack and keep the ecosystem from falling apart. This would be especially true in an environment that changed suddenly, such as when an asteroid hits the Earth with the force of a billion nuclear bombs.

Annihilation by asteroid (or comet!)

The 110-mile-wide crater at Chicxulub, Mexico is just one scar left from the comet or asteroid that hit the Earth 66 million years ago. The object was likely six miles across, and exploded on impact with enough force to leave a layer of debris across the entire globe. The impact also would have triggered seismic activity, including magnitude-11 earthquakes, tsunamis and maybe most importantly, volcanic eruptions.

Volcanic violence

There was plenty of volcanic activity in the late Cretaceous period, with some hot spots like the Deccan Traps in what is now India. Massive collections of volcanic rock speak to  massive eruptions, but new research indicates that, within a 50,000 year window, the asteroid that hit at Chicxulub may have exacerbated this volcanic activity, even on the other side of the world. The huge earthquakes that followed the impact may have disrupted and shifted the network of lava tubes and tectonic plates around the world in a sort of chain reaction, leading to increased output from volcanoes.

While magma is obviously dangerous, the real threat to life was in the air. Smoke and debris from the asteroid impact and volcanic eruptions would have been hard for plant life to cope with. Continuous eruptions would have then added sulphur dioxide and carbon dioxide to the atmosphere, shifting global temperatures and further stressing flora. Animals that weren’t poisoned by all this would have then had to battle the collapsing ecosystem as food sources ran scarce, especially for the larger, non-avian species that required large amounts of food to subsist on.

Fortunately, after half-a-million years, this apocalypse seemed to calm down. Volcanoes, like those in India, calmed and organisms seemed to begin to rise again, eventually leading to the rise of mammals. Let’s just hope we never have a chance to directly observe this theory in action.


My first grader said: Wow, it was like the dinosaurs’ grand finale! She then started inventing even more catastrophic scenarios, such as if the asteroid was “waiting” for just the right moment to hit. And if it was also carrying extra magma inside. And if…

Well, at least she wasn’t scared.

 

Source: Asteroid impact, volcanism were one-two punch for dinosaurs by Robert Sanders, Berkeley News

On October 1st, 2015 we learned about

Dampening dangers throughout your digestive tract

It might seem like your taste buds are there to add pleasure to your life, letting you enjoy a sweet chocolate, tangy nectarine or perfectly bitter coffee. The pleasure of tasting is actually a gift from our brains to keep us focused on finding the right things, because a lot of what our taste receptors are doing is actually trying to keep us safe. That’s true of the receptors in our mouths, and especially true for the receptors in our stomachs and even our colons. As fun as it might be to taste a great cup of coffee a second time in our belly, receptors throughout our digestive tract are keeping watch to ensure we’re not being poisoned.

Tasting toxins

Even with so many examples of tasty, healthy and life-affirming bitter foods, bitterness is actually a flavor animals have evolved to be wary of thanks to poisonous compounds like solanine. Things that are too bitter can be fairly revolting, and children usually have a higher sensitivity to such flavors than adults, which makes sense considering the larger threat of poison to a smaller body. Of course, in measured doses, some would-be poisons aren’t really a problem the way they were intended to be, and that’s where our stomach’s taste receptors come in.

Portioning versus purging

The taste receptors in our stomachs don’t trigger a sensation of taste of course, but they’re mechanically the same as what’s on your tongue. When the right molecule comes along, it can fit into the receptor on the surface of your cell, activating it. In your mouth, this activation sends a signal to your brain so the stimulation can be processed as taste. In your stomach, it’s automatically used to control the amount of bitter substances you may be about to digest. After a larger meal, too many bitter activations may tell your stomach to slow down and hold food longer. This way, you’ll be less likely to digest and metabolize a dangerous amount of a toxin at once, instead doling out small and presumably manageable amounts over time. It also means you won’t feel hungry too soon.

If you’ve somehow ingested too much of a bitter, poisonous substance, your colon is also looking out for you. In fact, the receptors in your colon can trigger a sort of retroactive poison-control, telling your gut to fill with water to flush your digestive tract. Instead of holding onto potential threats before they get out of hand like your stomach, your colon uses diarrhea to flush things out. Clearly, you want your stomach’s receptors to be good at their job to avoid such emergency measures.

 

Source: You Have Taste Receptors in Your Colon. Here's Why. by Esther Inglis-Arkell, iO9

On October 1st, 2015 we learned about

Harris hawks coordinate when pursuing their prey

Many species of animals live and work in groups. Herds of deer, zebras, etc. will move and graze together, relying on each other to keep watch for predators, and then add to the chaos that will hopefully result in a successful escape should danger arrive. There’s not a lot of clear cooperation in these behaviors though, much less what you’d call coordination. For that, you might need to look to Harris hawks (Parabuteo unicinctus), who have been seen not only coordinating with each other, but also relying on specialization and basic divisions of labor to make sure they get the most out of each hunt.

Roles and routines

Harris hawks in the southern United States have been observed using a variety of techniques in group hunts. They start by scouting for prey, with the hawks standing on each other’s backs in stacks of two to three birds, maximizing their view of their surroundings. Hawks with better vision seem to become the group’s designated spotter, while the others wait at the ready to provide support.

When prey is found, the hawks let the bird who found the rabbit or mouse take the lead unobstructed. The next two birds act as wingmen, ready to pick up the trail if the prey dives left or right, or if the first bird misses their initial strike. They can cycle through each member of the hunting party, minimizing the amount of breathing room for their target.

If the target does find shelter, they team jumps into new roles on the ground. Some hawks will attack bushes to flush prey out towards their teammates. If the target gets as far as burrow, one hawk might guard the burrow’s entrance, blocking it with their clawed feet while others pursue other openings.

Shared success

In each phase of the hunt, the nearly every hawk likely giving up the chance to make the kill themselves, and thus risking their next meal. The benefits of working together seem to outweigh this concern though, as they share their kills with each other, making the coordination worth it to each member of the team. It’s thought that the abundance of cover, in the form of shrubs, bushes and burrows, make this strategy worth it to the hawks. Working together must net more food on a regular basis than occasional feasts alone.

The origins of these sophisticated methods is the next focus of study. Harris hawks roost together, and researchers would like to figure out of cohabitation led to coordinated hunting, or the other way around. They plan to study other populations of Harris hawks in South America, looking for similar behavior patterns in their hunting. If these skills are somehow limited to the birds in the United States, the question of a local culture comes into play, as these advanced techniques might be taught rather than innate.

 

Source: Zoologger: The only raptor known to hunt in cooperative packs by Joshua Sokol, New Scientist

On September 30th, 2015 we learned about

Finding the bugs and bacteria that will dine on our debris

While petroleum products are made from oil extracted out of the ground, they become a huge problem when we try to put them back there. With the average American throwing away 185 pounds of plastic a year, it’s obvious that landfills aren’t a sufficient way to “deal” with the waste we generate. Recycling is a start, but certain types of plastic products, like Styrofoam, can’t be recycled directly into new packing peanuts, coffee cups, etc. New research from Stanford University is instead looking into even greener options, like recycling those cups into plants. We just need to find the digestive tract to do it.

As neat as it would be if we could eat a disposable coffee cup like some sort of caffeinated bread bowl, mealworms have been found to be much better suited to the task. Darkling beetle larvae were found to consume up to 39 milligrams of polystyrene per day. Since they are truly digesting the plastic, the waste products are the worms’ usual mix of carbon dioxide and droppings that will hopefully prove suitable for gardening and farming, thereby potentially making into our stomachs some day. While the worms are promising, researchers are also looking into their microbiomes to try to isolate the exact gut bacteria that are breaking up the Styrofoam.  If they could be cultivated outside the worms, it would be a more efficient method for processing large amounts of waste.

More plastic to go around

The mealworms are part of a growing search for biological agents capable of reducing our plastic waste footprint. They join the ranks of waxworms, larvae of Indian mealmoths, who have already been found to carry bacteria that eat polyethylene, the key ingredient in many plastic bags. Beyond terrestrial biodegraders, researchers also hope to find a bacteria capable of breaking down the growing collection of plastic trash in the oceans, although anything in the ocean would be harder to control than bacteria kept in a processing facility. To avoid yet another entry in the list of mis-managed invasive species, the ultimate goal would be to start engineering plastics that use some of the bacteria’s enzymes to break down more safely on their own, before the worms, moths and bacteria are really needed.

Source: Plastic-eating worms may offer solution to mounting waste, Stanford researchers discover by Rob Jordan, Stanford News Service