On July 23rd, 2017 we learned about

Studying babies’ brains by sampling the bacteria from their butts

Parents concerned about their infant’s future aptitude may soon be fretting over their diapers. There’s no special scent or consistency to be looking for, but scientists have found a correlation between the bacteria in babies’ poop and babies’ later performance on cognitive tests. The exact mechanism at work isn’t fully understood, but it suggests that the microorganisms that call our bodies, and especially our digestive tracts, home may somehow influence our brains.

A swath of one-year-olds had their diapers sampled and analyzed to see what microbes were living in their guts. It’s well established that our bodies are colonized by trillions of microbes, many of which are crucial to our health, helping us do everything from digest food to blocking out more harmful species of bacteria. We acquire these microbes starting at birth, and so it wasn’t surprising that one-year-olds’ microbiomes were starting to look similar to what you’d find in an adult.

Better with Bacteroides

When these babies turned two, they were then given a cognitive assessment that looked at a range of skills. These included motor control, perception and language development. The results were then compared against the bacteria that had been in these kids’ diapers the previous year to see if any particular batch of microbes matched up with higher test scores. While not a clear cause and effect, kids that had had more Bacteroides bacteria scored higher on these tests, suggesting that the microbes were somehow connected to cognitive development. Surprisingly, babies with more diverse microbiomes didn’t do as well on these tests, even though that has been previously linked to other health benefits like diabetes and asthma.

There’s no known mechanism that would allow for the bacteria to directly influence brain development at this point, but the correlation suggests this is worth looking into. Even if it turns out that the increase in Bacteroides is a side effect of something else that does directly help brains, understanding that relationship may someday prove beneficial. In the mean time, don’t worry about your baby’s poopy diapers any more than practicality already requires you to.

Source: In Baby’s Dirty Diapers, The Clues To Baby’s Brain Development, Scienmag

On June 21st, 2017 we learned about

How Zinnia Huit could summon and speak with every animal, great and small

Sciencing the Sisters Eight!

The last sister showcase her new power in The Sisters Eight is Zinnia, although it also becomes clear that she’s been using it all along. While most of her sisters have to wait their turn for their powers to manifest, Zinnia spends the entire series conversing with dogs, birds and most importantly, the family’s eight cats. However, Zinnia’s abilities go beyond being able to chat with pets in the house, as she’s also able to summon animals to her from near and far, a feat that would probably require multiple modes of communication.

Calling all critters

When Zinnia calls in her zoological cavalry, human onlookers are somehow excluded from receiving her signal. This isn’t that weird an idea, as many creatures make use of similar senses to humans, but in ranges outside our perception. Elephants, for instance, have been found to make long-distance calls to each other between 1 to 20 hertz, just below the average human’s hearing range. These low-pitched calls travel a long way though, being audible over six miles away in optimal weather. It’s unclear how Zinnia would produce such a sound, but if she could it could theoretically get the attention of everything from a pachyderm to a peacock, all of whom rely on low-frequency sound for long distance communications.

Other birds might be getting called in with magnets. If Zinnia were somehow creating a strong magnetic field from her body, she could conceivably manipulate the navigation functions of many migrating birds. The birds normally rely on sensing the Earth’s magnetic poles, but if Zinnia could somehow put out a stronger signal, she might be able to convince birds that she was their actual destination.

A final way to summon other species would be to emit a batch of pheromones. Zinnia’s Zaniness doesn’t really mention how many insects arrive at Zinnia’s behest, but bugs like moths rely on these chemicals to find each other over large distances, often to find potential mates in a relatively gigantic world. Pheromones have been found to cause insects to aggregate in a wide range of species, with Cecropia moths sometimes traveling as far as 30 miles to find a mate.

Cat chats

As cool as calling in a zoo’s worth of animals is, it’s still noteworthy that Zinnia regularly converses with cats. Cats are famous for being less socially oriented than other domesticated animals like dogs, but that doesn’t mean they don’t pay attention to what humans might have to say. After all, cats don’t meow to communicate with each other as much as they do it for the people in their lives, which indicates a pretty solid effort to share their thoughts with us, even if those thoughts seem to mostly concern when they’d like to be let in or out the front door.

If you’re not Zinnia, there are still ways to try to “speak” with your cat. Body language counts for a lot, and training a cat to do specific tasks is likely to work better if it’s built around gestures instead of vocal cues alone. Following this idea, facial expressions count for a lot with cats, and learning to read them can help you understand what’s on your kitten’s mind. Some expressions probably what mean what you’d guess they mean based on human faces, such as signs of stress. However, a long, slow blink is tied to being relaxed and at ease, and cats will do this for humans and other cats when their stress levels are low enough. On the other hand, one thing people likely misinterpret is purring— even injured cats will purr, and so it doesn’t always mean a cat is happy with it’s situation, but is more likely a way for the cat to request your continued attention. So a purr might mean help is needed, or that continued petting is still required.

Zinnia seems to take all these concepts, and crank them up to enable even more sophisticated communication with the fauna in her life. Researchers haven’t pinned down the body language for complicated statements like “stop stealing the other cats’ food while invisible,” but we do at least know that there’s a foundation for her chats. Even if we can’t herd cats (or flocks of birds and bugs) very easily, there are definitely ways to start “speaking” with them.

Source: Your Cat Is Trying to Talk to You by Melissa Dahl, Science of Us

On May 25th, 2017 we learned about

Biological components in fabric aim to make responsive and self-repairing clothing

If your wardrobe is feeling a bit lifeless, you’ll be pleased to know that researchers are looking into adding bits of biology to clothing, turning them into dynamic, changing pieces of fabric. Unlike work to create wearable electronics, these concepts shouldn’t require any new batteries or other power sources, as evolution has primed these cells and proteins to do the work without needing to be plugged in. At this point, neither project is worried about fashion as much as function, but that’s OK when you’re talking about self-repairing, shape changing pants and shirts.

Moving with microbes

The MIT Media Lab’s Tangible Media Group has recently unveiled their “biohybrid” workout suit, which is designed to help athletes stay cool and dry during a workout. To do this, they’re basically co-opting a lot of existing concepts, but putting them together in a new, shirt-shaped way. The cooling is still handled by sweat evaporating off the body to cool down, but that sweaty skin will have better access to the air thanks to the clothes’ built-in bacteria.

Now most people aren’t looking for more bacteria on their body, but these microbes are actually built into the fabric itself. Harmless bacteria like Bacillus subtilis is integrated into small flaps in the cloth, with those openings being clustered over where people sweat the most. As moisture, in this case from sweat, builds up, the bacteria naturally absorb it, and basically puff up like a wet sponge. Since they’re unevenly distributed on the clothing’s flaps, as they expand, they can cause the small flaps to curl open, exposing the sweaty skin to fresh air. Even having sweat-ports in your shirt isn’t your thing, the team is also looking at other applications for geometry-shifting bacteria, like lampshades that open up when exposed to heat, or shades that close in response to ambient humidity.

Sealed by squid proteins

If you just don’t like holes in your clothes, chemists at the U.S. Naval Research Laboratory in Washington, D.C. have got you covered, albeit covered in squid proteins. Squid suction-cups have been found to be very adaptable, and can basically be reshaped and fused into shapes needed to help the squid grab hold of prey. Researchers have now isolated the proteins that make this possible, and are looking into using it on common fabrics, like linen or wool.

The most pressing use for this idea is to help protective clothing, like hazmat suits, be repaired more easily, although there is interest in expanding it to wider public use as well. Since the proteins can basically “glue” two pieces of fabric together with water and some pressure, there’s a chance that it could someday be used to patch up small tears in clothes in washing machine.

For now, both sets of biologically-enhanced clothes aren’t available for general use, but as growing proteins and bacteria becomes more common in commercial processes, we might soon have clothes that really are closer to a second skin.

Source: MIT Has Designed a Workout Suit Covered With Living Cells to Keep You Cool by Leah Rosenbaum, Seeker

On May 10th, 2017 we learned about

Food on airplanes tastes bland because your taste perception breaks in the air

It turns out that there’s one unpleasant part of flying that’s not the airlines’ fault, at least not directly. The food served on commercial airlines has long been famous for being bland and unappetizing, although since every snack on planes is now sold at prices that would make a movie theater blush, we might not being paying attention to this as much. Still, there’s not a lot an airline can do to make food tastier, aside from make us eat it on the ground. That’s because flying at high altitudes demands an environment that basically breaks our sense of taste. Even your favorite homemade dish would taste wrong if you ate it at 30,000 feet.

The air up there

The mechanism behind this isn’t actually flying, or being in the sky. Your taste buds aren’t somehow sensitive to altitude or anything. The issue is primarily how the air in a pressurized cabin messes with your sense of smell. Our perception of a flavor isn’t just what receptors are triggered on our tongues, as the exact ratios of different smells we experience as we chew provides a lot of information about what we’re eating. So when you’re stuffed up, food seems to have less flavor because you can’t detect those smells as well, which brings us back to airplanes.

While airplanes do pressurize their cabins so that you have enough oxygen to watch a movie at 30,000 feet in the air, they’re not recreating atmospheric conditions on the ground. The air pressure in the plane is closer to sitting on a 6,000- to 8,000-foot-tall mountain, meaning there’s less air to move yummy smells around the cabin. That air is also exceptionally dry, with less humidity that many deserts. This makes the mucus membranes in your sinuses drier, and less smells get registered by your brain, meaning you can’t detect a food’s flavor as well.

Upended ingredients

Weirdly, not all flavors are affected equally. The air pressure issues seem to knock out salt and sweet perception more than other types of flavors, such as umami. This is tough, since small amounts of salt are often used to enhance sweet flavors, and recipes have to be rethought to taste normal in flight. Further throwing things off is the fact that large amounts of salt bring out umami flavors, so just throwing salt at a bland snack may end up confusing things. On the other hand, this also explains why people tend to enjoy some foods more in the sky— tomato juice that’s got more umami is apparently preferred by lots of people that would never order a Bloody Mary on the ground.

Even if perfectly rebalanced recipes were concocted, and the air pressure optimized again to better match eating at sea levels, airplanes would still have an ambiance problem. As much as taste pivots on the balance of smells and flavors, our dining experience actually depends on nearly all our senses. Lighting has been found to influence how we perceive food, as does ambient sound. Light levels vary on planes, but the noise of the engines is usually a constant 85 decibels. All that sound further erodes our perception of salt and sugar, although it does seem to boost how well we can detect cardamom, lemon grass and curry.

Most of the above is unlikely to be addressed by airlines any time soon. Perfecting and mass-producing recipes that work better in the air, or retrofitting planes to feel more like an afternoon at the beach is obviously costly, possibly even more than $10 for a sandwich. So the next time you fly, just try to stay hydrated as much as possible, and try not to think about how much salt and sugar you might be eating without even enjoying it.

Source: Why does food taste different on planes? by Katia Moskvitch, BBC Future

On May 4th, 2017 we learned about

Age and “sweet tooth” genes can make eating sugar less satiating

Apologies if this makes me a bad parent, but I’m not actually sure how much sugar my kids eat each day. I do know that it makes them very excited to do so, and so every possible spike in sucrose and fructose in their daily routine is something to be negotiated, connived or at least celebrated. In the case of my four- and eight-year-old, a lot of this love for sweets is probably tied to their ages— kids taste receptors don’t work the same way adults’ do, and their growth seems to help them use those calories too. If these preferences last past their 16th birthdays though, their mom and I may be to blame, not because of parenting, but because of genetics.

Dessert-oriented DNA

Danish researchers recently isolated what they believe to be a “sweet tooth” gene, FGF21. Two variations in this gene was associated with significantly higher amounts of sugar consumption on a daily basis among the 6,500 people who participated in the study. The more common variations of the gene help produce hormones that calm neurological reward responses, making sugar less exciting to our brains after a certain amount has been eaten. People with this genetic sweet tooth don’t seem to have that same cap, and happily consume more sugar without feeling sated by it. More troubling, there may this reward connection may mean these people are also more likely to consume more alcohol and cigarettes, although that hasn’t been explicitly proven yet.

Before you start blaming FGF21 for the last candy bar you ate, don’t forget the other sweet tooth gene, SLCa2. Identified in 2008, this gene produces a protein called GLUT2, which helps move glucose around the body and help us feel full after our blood sugar levels are normalized. In lab experiments, mice with a mutation on the FGF21 gene were prone to eating more food than other mice, and there may be a correlation with Type 2 Diabetes. Overall, a change in a single amino acid correlated with as much as 25 more grams of sugar than people without the sweet tooth mutation.

Caloric counterbalance

Importantly, neither sweet tooth gene mutation really synced up with serious health problems (although these test participants’ dentists may have a different opinion on that.) People with FGF21 mutations actually had lower body mass indexes on average, so if they were somehow eating more calories due to extra sugar, they were also making up for it elsewhere in their diets. People with SLCa2 mutations were similar— while they may have eaten anywhere from 3 to 15 additional grams of sugar than other people, they weren’t consuming extra calories as a result. They were just making sugar a bigger proportion of their diet. This may be problematic if the remaining calories aren’t providing enough vitamins, antioxidants and fiber, but by itself a sweet tooth isn’t necessarily a bad thing.

Source: Crave Sugar? Maybe It's in Your Genes by Dina Fine Maron, Scientific American

On May 1st, 2017 we learned about

Fish skeleton growth significantly stressed in microgravity

Humans have been sending fish to space since the 1970s. Fish were the first vertebrates to mate in orbit as of 1994. In 2012, group of Japanese rice fish, also known as medaka, journeyed to the International Space Station, not to breed or pilot any sort of seafood farming for future astronauts, but to act as a convenient stand-in for humans as we learn about microgravity. Like humans, the fish seem to be adversely affected by living in low gravity, and they conveniently start displaying symptoms almost immediately after entering Earth’s orbit. Even better, medaka (Oryzias latipes) are basically translucent, making it easier to see what’s happening in their bodies as it happens.

Fluorescent fish cells

Even though fish are separated from humans by millions of years of evolution, they share some fundamental biology with us, such as the mechanisms that recycle and create new bone tissue. Medaka also handle being transported well, spawn lots of offspring and have been studied extensively from various angles, making them a handy model organism for finding out how living in space affects a vertebrate’s bone development. We’ve known that living in microgravity can reduce bone density for some time, but the fish react very quickly to their new environment, so it’s possible to observe these changes in a practical time-frame, instead of waiting months or years to see results.

The fact that medaka have mostly translucent skin makes monitoring their bodily functions helped as well, but scientists wanted to go a step further to get the data they needed. This batch of astro-fish were genetically modified so that two types of cells associated with skeletal development would fluoresce under specific colors of light. This way, scientists could choose a specific light to watch these cells’ activity in the translucent bodies, all without disturbing the fish any more than necessary. This was also handy for the astronauts on the ISS, who are generally too busy to be doing vivisection studies of tiny fish in microgravity.

Making and breaking bone

The cells in question were osteoclasts and osteoblasts. Osteoclasts break down bone tissue that needs replacement or repair, whereas osteoblasts build the framework for bone cells to grow on. Unlike humans that take around 10 days to show any difference in bone development, the medaka fish kicked both types of cells into high gear from the start. Over the course of a week, the genes that govern these cells behaved significantly differently than on Earth. This experiment may help target future research, as the fish will likely be good models for a variety of future experiments, even beyond the regulation of bone tissue.


My kids asked: What happens to the fish now? Are they left in space?

These medaka can normally live for around a year in the wild, but they didn’t have that much time on the ISS. Their special tank was designed to handle feeding, temperature control, simulated day and night-cycles of light, plus monitoring equipment for scientists on Earth to observe their experiment. However, these deluxe accommodations only had filtration systems intended to last 90 days, so a full year in space wasn’t in the cards. That was probably enough time for the fish to mate and spawn though, possibly for as many as three generations of medaka.

Astronauts obviously didn’t flush any dead fish down their specialized toilets, but the medaka probably didn’t make it back to Earth either. That’s not to say that no animals ever return to their home planet, as a batch of zebrafish were safely brought back from the ISS in 2016… most likely to be dissected.

Source: Fish Don’t Do So Well in Space Read more: http://www.smithsonianmag.com/smart-news/fish-dont-do-so-well-space-180961817/#vUzFAxXI6SmPahjk.99 Give the gift of Smithsonian magazine for only $12! http://bit.ly/1cGUiGv Follow us: @SmithsonianMag on Twitter by Danny Lewis, Smithsonian

On May 1st, 2017 we learned about

The coordination and communication of brainless bacteria

Cooperation is a complicated process. Different parties need to understand each other’s goals well enough to adjust their behavior, even to the point of curbing their initial desires to find a compromise. With the number of variables in play, it’s even been suggested that cooperation is linked to more sophisticated brains, such as when a social lion might outperform a solitary leopard at cognitive tests. Or… it might be something that even ‘lowly’ fungi and bacteria can engage in, with absolutely no brain required.

Managing meal times

Bacteria colonies can grow into distinct populations, complete with an outer protective layer that seals in its members. These biofilms work together with the bacteria inside, but may end up competing with other bacterial biofilms for resources, even if they’re all the same species of bacteria. Rather than battle for every last speck of food in the petri dish, researchers found that Bacillus subtilis biofilms appear to coordinate their activity so that there’s enough food for both populations.

Within each biofilm, bacteria can communicate with each other, even using electrical signals that get passed between each cell. In aggregate, these signals can fall into a shared pattern of oscillating signals, and those signals have been observed to be linked to stimuli like the amount of food available at any given moment. When two biofilms meet up, their oscillations can be synced up, which results in everyone trying to eat the same resources at the same time. This was fine if there was a lot of food for each biofilm, but if food was harder to come by, they instead shifted to asynchronous oscillations. The bacteria basically adjusted their timing so that neither group was engaged in its “eat now” portion of activity at the same time, which meant they weren’t directly competing anymore. This generally resulted in better growth for both biofilms.

Sharing through smell

Electrical activity between similar cells isn’t the only form of microbial communication either. Serratia, a soil bacteria, has been observed trading information with Fusarium, a fungus that is pathogenic to plants. The two organisms weren’t exactly engaged in social banter with each other, but each was seen producing and reacting to chemicals known as terpenes. With no specific sensory organs for hearing or sight, the microbes were communicating with smells.

Further changes in behavior weren’t immediately tied to the terpene exchange, but it’s thought that smell is likely the most widely used medium for communication, with terpenes in particular being the lingua franca among most microorganisms.

Source: Distinct bacterial communities share nutrients for the common good, Scienmag

On April 30th, 2017 we learned about

Scientific tips on how to survive being swallowed

If you should find yourself being eaten by another creature, what are your odds of survival? As a human, anything putting you in it’s mouth is probably going to need to chew you up a bit first which will probably end things right away, but if you find yourself pulling a Jonah and being swallowed whole, there may be some chance of making it out of a creature’s belly alive. Ignoring scenarios involving divine intervention and parasites that intend to be swallowed in order to nest in a creature’s gut, scientists have found a handful of creatures that made it out of a another creature’s belly alive. Based on those creatures’ experiences, here are some guidelines to help you make the most of a dire situation.

Make it past the mouth

The first step is to slip past the mouth without being crushed. This isn’t entirely in your control of course, but try to be much smaller than your predator to require less chomping and crushing. Toads and birds are a good choice too, since they generally just gulp things down whole, skipping any sort of chewing activity.

Don’t be digested

Once you’ve “safely” made it to your predator’s stomach, it helps to have some sort of outer covering that will protect you from stomach acids and other digestive enzymes. Snail shells, layers of mucus coating your body, and even reptilian scales might survive the trip. If you go with a scale-like covering though, you’ll need to make sure they’re tightly interlocking, otherwise the corrosive stomach juices might find their way to your more sensitive skin underneath.

Breath slow or move fast

Assuming your body is retaining its structural integrity, you’ll need to have a plan for the lack of oxygen in a predator’s digestive tract. Once again, being small and relatively low-energy like a worm or even a snake will likely help, as a warm-blooded mammal will likely need more oxygen per second to keep their metabolism going. If you do need O2, it’s a good idea to hurry through the digestive tract as fast as possible until you reach air on the other end, rather than waiting for your predator’s intestines to slowly push you along. Even then, you might still be in trouble— a brahminy blind snake (Indotyphlops braminus) was once observed successfully wriggling out of a toad’s digestive tract once, but the escape took its toll, and the snake died within five hours of its ordeal.

Poison your predator

If wriggling through intestines seems like too much of a risk, consider the tactics of the rough-skinned newt (Taricha granulosa). When swallowed, the newt can excrete enough toxins to kill it’s predator before the stomach acid can really cause harm. At that point, the newt only has to crawl back out the esophagus and mouth, skipping its predator’s rear end entirely.

Once you’ve escaped death by digestion, the rewards of your efforts may extend beyond being able to see daylight ever again. Whoever ate you is likely to have traveled while you were on the inside, and if you’re healthy enough, may help you spread your species to new territories. Once again, try to be swallowed by a bird, because they’ve been known to take their undigested meals to new islands that otherwise would have been completely inaccessible.

Source: There are animals that can survive being eaten by Sandrine Ceurstemont, BBC Earth

On April 24th, 2017 we learned about

The many ecological rewards of sowing edible seaweed

“Where does seaweed come from?” my four-year-old asked, while stuffing crispy nori snacks into his mouth.

It seems like an obvious, I mean, it says “sea” right in the name, but he’s four, and I realized that beyond saying “the ocean,” I couldn’t really explain much more than that. I could picture kelp forests that were home to various other plants and animals (“like in Finding Dory!“) but really had no image of how humans harvest the stuff. Which, it turns out, they’re doing more and more all over the world.

The first thing about seaweed is that it’s not really a weed, because it’s not a plant. There are folks out there who try to frame it as a vegetable in order to make the idea of cooking it more approachable, but edible kelp is a form of multicellular algae. Being algae is actually part of what makes growing kelp so cool, because it happily gobbles up nitrogen and carbon dioxide out of the water. On the negative end of the spectrum, excess nitrogen, such as from fertilizer runoff, can cause very harmful blooms of algae, such as with “red tides.” Brown kelp like oarweed (Laminaria digitata), on the other hand, can take that nitrogen and make it into something tasty and nutritious. The fact that it essentially cleans up the ecosystem and increases biodiversity just makes things that much more appealing.

Farming among fish

To raise seaweed, a lot of farmers around the United States are looking at methods that aim to minimize disrupting local ecosystems. Kelp can be grown along pre-spored wires suspended in the water. In “3D” farms, the seaweed is then raised alongside other seafood, like clams and mussels. This allows for a lot of healthy biodiversity in a small footprint, requires no real “inputs” from the farmer in the way of fertilizers or water, and leaves a space that can still be used by recreational fishermen and swimmers. The presence of shellfish means that water quality is tested frequently, so the kelp is a lot more pristine than it absolutely needs to be. In other scenarios, kelp is being raised not for food, but as a sort of remediation device, sucking up heavy metals in water supplies where no food can be raised.

Seaweed has been harvested to some degree since at least the 17th century, but new uses for the algae are making it a very popular crop these days. While farmers struggle to keep up with orders, it’s important to remember that not all production is equal. In some places, farmers are following in the footsteps of their terrestrial counterparts and tearing out native species to accommodate their cash crop. For seaweeds, people are usually removing mangroves and eelgrass, which ends up lowering water quality on top of reducing biodiversity.

Pick and process it

So to get back to my kid’s question, seaweed is farmed in the ocean, either to be eaten, clean the water, or make a variety of other products from biofuels to personal lubricants. On a small scale, you can simply cut off a single blade (the leafy bits) or the central stalk— just take care not to cut too close to the holdfasts so the alga can keep growing. On a larger scale, rent some shoreline and be ready to haul out multiple tons of the stuff on a regular basis by hauling your lines out of the water.


My four-year-old asked: Does cutting the seaweed hurt it?

It does stop that section from growing, but I think the real question here was about if a non-plant feels things like sentient animals do. Some algae do have photoreceptors, but as far as I can tell, farmed brown algae doesn’t have any nervous system it could use to sense or experience the process of being harvested.

Source: Kelp For Farmers: Seaweed Becomes A New Crop In America by Craig Lemoult, The Salt

On April 17th, 2017 we learned about

Freezing Arctic winters extend the lifespan of woolly bear caterpillars

The Isabella tiger moth isn’t nearly as its name might imply. The one- to two-and-a-half inch moth has only the faintest of stripes on its yellow-orange wings, with the clearest markings consisting of a smattering of dark spots here and there. They only live a few days, giving them just enough time to find a mate before they die, putting a quick end to what may have been a life as short as a single summer, or as long as 14 years. This is because the most remarkable thing about these moths is the range of habitats they live in, and the lengths they go to survive their adolescence.

Coloration unrelated to cold

The larval stage of the Isabella tiger moth (Pyrrharctia isabella) is a bit more descriptive and daring its brief time as an adult. The caterpillars, often referred to as banded woolly bear caterpillars, are covered in black and coppery-orange hairs, with the lighter color forming a single band around the insects’ middle. Folklore states that the width of the copper-colored band will predict the severity of the coming winter, with more black hairs indicating a harsher season. In reality, the different colors are the result of a molting process, as the orange hairs take up more and more of the caterpillar’s body as it grows larger. The hairs actually have very little to do with cold or snow, even though the caterpillars are known for surviving winters in the Arctic.

Woolly bear caterpillars in places like Florida or Virginia don’t have to worry much about winter, as they’ll probably find enough food to fatten up and pupate in a single summer. For those caterpillars living further north, spring and summer feels significantly shorter, leaving them with a lot less time and foliage to work with. Instead of giving up on the tundra, woolly bear caterpillars instead enter a form of dormancy called quiescence, hitting the pause button on their life until their world thaws out again months later.

Waiting out winter

Insects make use of two forms of dormancy. The first is called diapause, which is comparable to hibernation in mammals. It is a form of low metabolic function, and can be cued by environmental or genetic triggers. Importantly, it’s a genetically-determined cycle, and takes a while to recover from once the correct conditions are satisfied.

The second form of dormancy is quiescence, which may appear very similar to diapause at first. The key for the woolly bear is that it’s not on an internal clock, and is more responsive to environmental conditions. This allows the caterpillar to hide out under leaf litter for the Arctic winter, resuming activity the moment things are warm enough to resume foraging. Minimal metabolic functions are less likely to be damaged by freezing temperatures, which the caterpillars back up with a cryoprotectant that keeps their circulatory system from being damaged by ice crystal formation.

By safely freezing through winters, Arctic woolly bears can slowly eat their way through as many as 14 summers. Once sated enough to build a cocoon, they still only have a few days to find a mate as a tiger moth, with no way to hit the pause button again if the singles’ scene doesn’t work out. It seems that even after surviving being frozen solid, you only get so many chances to get things right.

Source: The Woolly Bear Caterpillar in Winter by Karen McDonald, The Infinite Spider