Curio Cabinet / Nerdy Curio

Is this as big as they can get? It’s hard to imagine otherwise. Astronomers at the University of Portsmouth have found what could be the largest black hole ever discovered, according to a paper published in Monthly Notices of the Royal Astronomical Society. Located around five billion light years away in the Cosmic Horseshoe galaxy, the black hole is at least one of the top 10 largest ever discovered. It’s not such a surprise that one of the most massive black holes would be found within one of the most massive galaxies, but the sheer scale is still a bit jarring. The supermassive black hole located at the heart of the Milky Way galaxy, Sagittarius A*, contains the mass of 4.15 million suns. On the other hand, the new discovery is an ultramassive black hole and is estimated to have the mass of 36 billion suns. What might be even more surprising is how it was discovered. Unlike most known black holes, this one does not have an accretion disk. That means it’s not actively consuming the matter around it, and that it lacks the telltale x-ray emissions produced by accreting matter. Instead, the black hole was given away by its sheer mass, which warped the space-time around it enough to cause gravitational lensing, a phenomenon in which the light coming from behind an object is visible along its edges. Even the Cosmic Horseshoe itself gets its name as a result of this phenomenon, since it is framed by a horseshoe-shaped ring of light. It must run in the family.

[Image description: A starry sky with the milky way visible.] Credit & copyright: NPS/Patrick MYers, Asset ID: 707ecd39-53dd-47a2-8dad-33178eac3992, National Park Service Digital Asset Management System. Constraints Information: Public domain: Full Granting Rights.
 

That’s not an enormous bird blotting out the sun…it’s a mammal! Flying foxes, specifically the 60 or species in the genus Pteropus, are the largest bats in the world. Those suffering from a bit of a bat phobia have nothing to fear, though. These high-flying mammals don’t drink blood or even eat insects; they feast on fruit.
 
Flying foxes mainly live in tropical regions of Asia, Australia, Madagascar, and some Pacific islands. There, they have abundant, year-long access to all sorts of fruits, and they certainly make the most of it. Many species of flying foxes eat up to half their body weight in fruit, pollen, and nectar each day. All that food helps fuel their impressively large bodies. The biggest species of flying fox, the giant golden-crowned flying fox, has an average wingspan of around 4.9 to 5.6 feet and can weigh up to three pounds.
 
A flying fox’s environment must have enough food to support not just a few individual bats, but entire colonies. Most flying foxes are social, living in groups that can range from a few dozen bats to several hundred. Unlike many, smaller bats, which remain in a fixed location each year, flying foxes are nomadic. Each year, they can fly thousands of miles in search of food. Luckily, flying foxes help maintain the very fruit they depend on to live, spreading pollen via their fur and seeds via their droppings.
 
Like most bat species, flying foxes are nocturnal. During the day, they hang upside down, high in the forest canopy (with young bats clinging to their mothers until they’re ready to fly on their own.) There, they sleep and groom one another while waiting for nightfall. Flying foxes’ entire lives revolve around trees, which means that habitat destruction, especially as part of the logging industry, is particularly devastating to them. Sadly, nearly half of all flying foxes are either threatened or endangered. Here’s hoping that intensifying conservation efforts can keep these gentle giants airborne.

 
[Image description: A large, brown-colored bat flying against a blue sky.] Credit & copyright: Map9994, Wikimedia Commons. This work has been released into the public domain by its author, Map9994, at English Wikipedia. This applies worldwide.

Whether you’re a human being or a cockroach, pregnancy is draining. According to a paper published in the Journal of Experimental Biology, researchers at the University of Cincinnati have discovered that some species of cockroaches need more sleep when they’re pregnant, just like people. The Pacific beetle-mimic cockroach (Diploptera punctata) is something of an oddball among insects. Instead of laying eggs like most roaches, they give live birth, but that’s not all. During the three-month gestation period, these roaches feed their young from a broodsac using milk protein. This is called viviparity, and it’s somewhat similar to the way mammals use a placenta to nourish their young during gestation. The similarities to mammals don’t end there: just like human mothers need to get plenty of sleep, these roaches also require sleep for healthier gestation and offspring. The need for rest is so important that, according to the research, pregnant D. punctata don’t travel as far in search of food, indicating an aversion to risk-taking behavior. The relationship between sleep and pregnancy complications in humans are poorly understood, which is why the roaches are of such interest to researchers. In humans and mammals in general, sleep disturbances can significantly impact embryo development, and if similar issues affect D. punctata, studying the roaches might give some clues as to why. No matter the species, being a mom is hard work.

[Image description: A close-up photo of a brown cockroach.] Credit & copyright: Junkyardsparkle, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
 

Even two dozen limbs can’t help you outrun a pandemic. Since 2013, billions of sea stars, also known as starfish, have died due to a mysterious wasting disease. Now, scientists have finally pinpointed the bacteria responsible for the plague, giving hope that conservation and disease-management programs can save these unique ocean creatures. No species was hit harder by the disease than the sunflower sea star, whose population has decreased by a whopping 90 percent since the plague was first noticed.
 
Sunflower sea stars come in a variety of colors, from reds, yellows, and oranges, to various shades of purple. Unlike sea stars that resemble a traditional five-pointed star, sunflower sea stars have between 16 and 24 limbs, making them look more like sunflowers. They differ from other sea stars on the inside, too. Their skeletons aren’t solid, like most sea stars’. Instead, it’s made of disjointed, bone-like discs, or ossicles. This makes sunflower sea stars extremely flexible, which comes in handy when hiding from predators and while hunting. Though they may not look much like predators, sunflower sea stars are just that. Their arms are covered in eye spots which help them discern light from dark and allow them to locate potential prey. The bottoms of their limbs boast up to 15,000 thin, almost hair-like tube feet, allowing them to crawl across the ocean floor at speeds of up to 3.3 feet per minute. For sea stars, that’s pretty fast! It’s certainly speedy enough to hunt down their favorite prey: other invertebrates. Sunflower sea stars are completely carnivorous, dining on sea urchins, clams, and crustaceans.
 
These many-armed critters have a large range across the Northeast Pacific Ocean, from the coastal waters of Alaska to Mexico. Unfortunately, in recent years their population has dwindled due to a devastating, worldwide plague of sea star wasting disease. The mysterious illness causes sea stars’ bodies to break out in lesions and completely disintegrate. Since 2013, over five billion sea stars have died from the disease. Now, researchers have finally discovered the cause of the illness: a bacteria called Vibrio pectenicida. With this knowledge, steps can finally be taken to save the sea stars. That might involve breeding sea stars that are immune to the bacteria and then releasing them into the ocean, or feeding wild sea stars probiotics to help them fight the bacteria off. Hopefully, this isn’t the last we see of these sunflowers of the sea.

 
[Image description: A group of reddish-colored sunflower starfish in shallow water.] Credit & copyright: NPS Digital Asset Management system. Asset ID: 2D7F9806-A3B5-ABD1-9B952DA866AA90E2. Constraints Information: Public domain.

Some voices can be heard for a country mile. According to a paper published in JASA Express Letters, researchers at Indiana University have found that twangy voices are the easiest to hear over loud noises. Apparently, twangy, female voices are the easiest to understand in an environment filled with neutral noise. However, “twangy” doesn’t just refer to the stereotypical country accent, but includes those found in major U.S. cities like New York and Chicago. These voices have what the researchers called “bright” and “brassy” qualities. In the study, researchers took four male and four female participants with twangy voices and had them record speech samples. When played along with background noises like plane or train sounds, listeners were able to understand the twangy voices better than ones with a “neutral” accent. Although the reason for this isn’t clear, it may have to do with the fact that twangy voices tend to have a higher pitch than neutral ones. High-pitched sounds are perceived more clearly than low-pitch sounds, especially when ambient noise is also low pitched, which it often is. They also believe that a twangy timbre might have applications in voice therapy, which allows the speaker to “maximize acoustic output while minimizing effort.” You could call it a different kind of talk therapy.

[Image description: A digital illustration of a word bubble with three exclamation points inside, with four curved lines representing soundwaves.] Credit & copyright: Author-created image. Public domain.
 

These mermaids are a bit chunkier than the fairy tales claimed. Famously mistaken for mermaids at various points in history, manatees have managed to remain humble, drifting through warm, shallow waters at a leisurely pace of around five miles per hour. These friendly aquatic mammals are often compared to seals, but their true lineage is much more surprising.
 
Manatees have earned their distinction as gentle giants. They can grow up to 10 feet long and weigh up to 1,200 pounds, on average. They’re friendly enough to be tourist attractions, floating alongside snorkeling travelers. They’re not the only giants in their family tree, either. Manatees’ closest living relatives are elephants, though the two species obviously evolved in very different directions after splitting from their common ancestor around 60 million years ago. Their interesting lineage and general appearance, from their cow-like faces (from which they get their nickname “sea cow”) to their pudgy bodies, makes it all the more intriguing that they were once mistaken for mermaids. It does make some sense, considering that early Europeans often painted animals from the “new world” without ever having seen them in person, which could lead to discrepancies when one actually came across them. After seeing manatees for the first time in 1493, Christopher Columbus wrote, “Yesterday, when I was going to the Rio del Oro, I saw three sirens that came up very high out of the sea. They were not as beautiful as they are painted since, in some ways, they have a face like a man.” Despite Columbus’s scathing assessment, Manatees (along with dugongs) are part of the order Sirenia, named after mythical sirens, or mermaids.
 
Manatees frequent coastal waters in certain areas of North America, South America, the Caribbean, and West Africa, where they live mostly solitary lives, feeding on aquatic vegetation like algae and kelp. Although West Indian Manatees (which includes those sometimes called “Florida manatees”) haven’t been listed as endangered since 2017, they still face plenty of threats. They’re too big to be harmed by most natural predators, but habitat loss, dangerous pollution, and collisions with boats have all taken a toll on global manatee populations. Boat collisions can be especially deadly, and conservationists suggest that boaters avoid shallow waters and wear polarized sunglasses to better spot manatees beneath the surface. Crashing into a mermaid has got to bring bad luck.

 
[Image description: A manatee floating underwater surrounded by small fish.] Credit & copyright: Ramos, Keith, USFWS. USFWS National Digital Library. Public Domain.

When playing the genetic lottery, your odds may be worse than a coin flip. A recent paper published in Science Advances by researchers from Harvard University shows that the odds of a couple giving birth to a male or female baby might not be quite as even as previously thought. Aside from intersex conditions like extra chromosomes, androgen insensitivity syndrome, and other cases where a person’s gender doesn’t necessarily match up neatly with their chromosomes, the formula for a male or female person is simple. Two X chromosomes, one from each parent, results in a girl. One X chromosome from the mother and one Y chromosome from the father results in a boy. And since each sperm has a 50/50 chance of carrying either an X or Y chromosome, it would seem that the birth rate for each sex would be the same. Not really, though. Researchers looked at data regarding 58,007 women in the U.S. who collectively gave birth to 146,064 children between 1956 and 2015. Instead of finding a simple binomial distribution of the sexes, they found a beta-binomial distribution, meaning that families could tend to skew toward producing one sex more than the other. The researchers compared it to a weighted coin toss, where the odds weren’t completely random. One of the telltale signs was that it was much more common than it should have been for some families to have all boys or all girls. A possible factor appears to be the age of the mother, as women 28 and older had an elevated chance of giving birth to multiple children of one sex over another. Researchers noted that the data might be affected by a behavior they call “coupon collecting,” which is when a couple continues to have children until they have a child of their desired sex. Compared to actual coupon collecting, that sure sounds expensive.

[Image description: The symbols for “female” and “male” with a pink-and-blue background.] Credit & copyright: Author-created image. Public domain.
 

Are those raindrops on the water’s surface? Or something far more lively? Water striders are some of summer’s most common insects, but that doesn’t mean that their incredible ability to “walk” on water should be taken for granted. These insects are masters of physics. In fact, they’re so good at what they do that some even live in the open ocean.
 
There are nearly 2,000 species of water striders, all in the family Gerridae. Most are less than an inch long, as they must be light enough to stand on the surface of water. They do this by utilizing water’s natural surface tension. Surface tension happens because water molecules like to stick close together. Below the surface, these molecules are evenly spaced because of the push and pull of other, nearby water molecules. At the surface, however, there are no water molecules to push down from above. Thus, molecules group more closely together there, forming an extremely thin, film-like barrier. It’s this “film” that water striders have evolved to walk on. The secret is in the long, water-repellent hairs called hydrofuge hairpiles that cover their bodies. These hairpiles contain even smaller microhairs that are grooved to trap tiny pockets of air. This makes them hydrophobic, or water-repellent. This, combined with water’s surface tension and their small body size, allows water striders to lift themselves into a standing position on the surface of water. They can then move forward in a gliding motion by pumping their three sets of legs.
 
Water striders are found on every continent except Antarctica, and some species in the Halobates genus, commonly called sea skaters, even live in the open ocean. They are both predators and scavengers, mostly eating terrestrial insects that fall into the water. They’ll also stalk and eat other aquatic bugs, like water beetles and snails. Their specialized jaws are designed to pierce the exoskeletons of insects and suck out the juices inside, yet the vast majority of water striders pose no threat to humans. Their jaws are too small to pierce human skin, but they are perfectly able to eat harmful, disease-spreading insects like mosquitos. Who knew these aquatic ballerinas were performing a public service?

 
[Image description: A close-up photo of a brown water strider “walking” on top of water.] Credit & copyright: TimVickers, Wikimedia Commons. The copyright holder of this work has released it into the public domain. This applies worldwide.

How granular do you like your clock to be? When it comes to timekeeping, it doesn’t get nittier or grittier than the aluminum ion atomic clock developed by researchers at the National Institute of Standards and Technology (NIST), according to a paper published in Physical Review Letters. Far from their pendulum or spring-based predecessors, atomic clocks, first invented in 1947, used atoms to keep track of time. Atomic clocks mostly use cesium atoms today, and they work by energizing the atoms with laser light tuned to its resonant frequency to make them “tick.” Early atomic clocks weren’t particularly accurate because the instruments used to measure the frequencies and deliver the light weren’t accurate themselves. Today, though, atomic clocks are so accurate that if they had existed since the beginning of the universe 13.8 billion years ago, they would still be accurate to within one second. The newest atomic clock developed by NIST goes even further using aluminum ions. Despite having the potential to be more accurate, aluminum ions weren’t used before because they don’t react much to lasers. The solution was to pair them with magnesium ions, which don’t have the steady ticking rate of either cesium or aluminum. What they can do is be controlled by lasers and cool down aluminum ions, allowing the laser to interact with the aluminum ions in a process called quantum logic spectroscopy. The result is a clock that can measure time with 19 decimal places of accuracy. Try that with a vintage grandfather clock!

[Image description: A clock face with Roman numerals inside a glass dome atop a wooden stand.] Credit & copyright: Simon Willard, American, 1825–30. The Metropolitan Museum of Art, Gift of Mary B. Walton, in memory of her husband, John S. Walton, 1991. Public Domain.
 

Stroll by a stream this summer, and you’ll almost certainly see these colorful sunbathers…even in places they’re not supposed to be. Red-eared sliders are some of the most common freshwater turtles on the planet, both in the wild and in pet stores, but they’re native only to the southeastern U.S. and northern Mexico. Beloved as they are in many places as a sign of sunny weather, these beautiful turtles wreak havoc as an invasive species in places as far away as Australia.
 
Red-eared sliders are medium-sized, freshwater aquatic turtles. Females are slightly bigger than males, growing to around 12 inches long while males reach average lengths of just nine inches. Like many turtle species, they’re fairly long-lived, with a lifespan of around 30 years in the wild and up to 40 years in captivity. While baby red-eared sliders eat mostly insects, adults eat mostly aquatic plants, but they won’t pass up a chance to eat small fish or scavenge meat if the opportunity arises. Their varied diets make them adaptable to any environment with plentiful water and sunlight. In places with cold winters (including parts of their natural range) they can go into a semi-dormant state called brumation to survive the lower temperatures.
 
As for how these seemingly harmless turtles became worldwide pests, the problem isn’t them—it’s us. Red-eared sliders are named for the bright red stripes on their heads, and they also have bright yellow stripes on the rest of their green bodies, making them attractive pets. In the 1950s and 60s, baby red-eared sliders were sold at many American dime stores en masse as a novelty, and were even shipped through the mail in some places to be cheap pets. While hatchlings are just a few inches long, they quickly grow into adult turtles who need plenty of space and a specialized diet. Rather than adapt to their pet’s needs, some owners instead released them into the wild, even in areas far removed from red-eared sliders’ natural habitats. Today, invasive red-eared sliders can be found on every continent except Antarctica. In places like Japan and Australia, red-eared sliders’ adaptability makes them extremely dangerous, as they upend fragile ecosystems by gobbling up the plants, fish, and insects that native species need to survive. Although conservationists the world over are working to remove the invasive turtles from places they don’t belong, they’ve got a long road ahead of them…and turtles aren’t exactly known for their speed.

 
[Image description: A red-eared slider swimming with its head out of water, surrounded by duckweed.] Credit & copyright: Vassil, Wikimedia Commons.

These mountains look cool, but they can be real hotheads. Researchers from the University of Wisconsin–Madison have presented a study at the Goldschmidt Conference in Prague suggesting that dormant volcanoes around the world may become more active as a result of melting glaciers. First, some clarification: there are three main volcano classifications depending on their level of activity. “Active” means that the volcano has erupted during the Holocene epoch (the last 11,650 years or so) and has the potential to erupt again in the future. “Extinct” means that, as far as anyone can tell, the volcano is unlikely to ever erupt again (though it happens from time to time). “Dormant”, on the other hand, means “potentially active,” as in, it’s an active volcano (the first classification) that’s just not erupting presently, as opposed to “actively erupting,” which means magma is currently coming out of the ground.
 
A lot of factors contribute to a volcano’s dormancy, and scientists have found that glaciers are one of them. Researchers tracked volcanic activity by measuring the radioactive decay of argon in crystals formed in magmatic rock. They then compared that to the level of ice cover during the peak of the last ice age. What the data seems to suggest is that the ice cover acted as a lid, inhibiting eruptions. As the ice melted, volcanoes became more active. Currently, there are an estimated 245 dormant volcanoes buried under three miles of ice, and many of them are in Antarctica. Once these begin to erupt due to the reduction in ice cover, it may create a feedback loop as the eruptions themselves further melt the ice. It seems there will be an icy reception before things really heat up.

 
[Image description: A portion of the Andes mountain range between Chile and Argentina, photographed from far above.] Credit & copyright: Jorge Morales Piderit, Wikimedia Commons. The copyright holder of this work has released it into the public domain. This applies worldwide.
 

These critters are as American as apple pie, but a whole lot bigger! North American bison, also called buffalo, are the largest land animals in North America and some of the most historically significant. Yet, we almost lost them altogether. Overhunted throughout the 19th century, there were fewer than 600 bison left in the U.S. by 1889. Today, their numbers have recovered drastically, but these gentle giants still have a long way to go.
 
There are two species of bison: The North American bison and the European bison. North American bison are often called buffalo, but they aren’t actually buffalo at all. Real buffalo, like cape buffalo and anoa, live in Africa and Asia. However, bison are closely related to buffalo and share many traits with them, since they’re all bovines—members of the family Bovidae’s subfamily, Bovinae. As such, they share many attributes with buffalo, including their large size, horns, and hooves, as well as behavioral traits like living in herds. Bison are famous for their fluffy winter coats, which help them survive harsh, blizzardy winters in places like the Northern Great Plains. That’s not to say that bison are sweet and cuddly, though. They are massive, powerful animals; males can stand up to six feet tall and weigh up to 2,000 pounds. Like any wild animal, they can become aggressive if approached, especially during mating and calving season. It’s a fact that tourists sometimes learn the hard way when they don’t obey rules in places like Yellowstone National Park, where the largest bison population in North America roams free.
 
Bison first appeared in North America during the late Middle Pleistocene epoch, between 195,000 and 135,000 years ago. Before European colonists began settling in North America en masse in the late 15th century, there were around 30 million bison roaming in what is now the United States. Many native tribes relied on bison meat and hides, with some, like the Plains Indians, focusing many parts of their lives around the movements of bison herds. However, as colonist aggression toward native tribes increased and native peoples lost control of more and more land, the bison population dwindled. During the American Indian Wars of the 17th, 18th, and early 19th centuries, bison were deliberately killed by colonists as a means of harming native peoples and to feed colonial soldiers. By the 1880s, there were as few as 300 bison left in what is now the United States. The species was on the brink of extinction.
 
Luckily, private organizations and ranchers stepped in to save North American buffalo, keeping herds on private land where they couldn’t be hunted. In 1902, 21 bison from private owners were placed in a designated area at Yellowstone National Park. Eventually, they were reintroduced to the wild, and began breeding with Yellowstone’s existing wild population. In 1905, the American Bison Society started a bison breeding program that also helped spread awareness about the importance of wild bison. Theodore Roosevelt aligned himself closely with the organization and even served as its honorary president for a time. Today, thanks to over a century of conservation efforts, there are roughly 31,000 wild bison in the United States. It’s a far cry from the millions that once roamed here, but it’s a whole lot better than extinction, and that’s no bison hockey!

 
[Image description: An adult and baby bison standing on a shrubby plain.] Credit & copyright: Anna Weyers Blades/USFWS. Public Domain.

Getting rid of plastic is a pain, but what if it was a painkiller? According to a paper published in Nature Chemistry, scientists at the University of Edinburgh in the U.K. have genetically engineered a strain of E. coli that is capable of breaking down plastic and turning it into acetaminophen. It sounds outlandish, but it’s not as crazy as it seems. The E. coli in question isn’t the same type that makes people ill. This strain is capable of carrying out a chemical reaction called a Lossen rearrangement. It’s a phenomenon that has never been observed in nature before, and until now was only seen in harsh laboratory conditions previously thought to be incompatible with life. Yet, when chemists added polyethylene terephthalate (PET), a type of plastic commonly used in food packaging, into a culture of their specially-engineered E. coli, the bacteria used a Lossen rearrangement to turn plastic molecules into acetaminophen.
 
Also known as paracetamol, Acetaminophen is an over-the-counter painkiller that most people have taken at some point, though they might not know that it, too, is a petroleum derivative. Just as it takes a lengthy process to turn crude oil into helpful pills, researchers had to take several steps to get their E coli to produce something useful. First, they took E. coli that could turn PET into para-aminobenzoic acid (PABA), and added genes from mushrooms and soil bacteria that could turn PABA into acetaminophen. The result was a strain of E. coli that could create acetaminophen from PET in less than 24 hours. That’s one headache solved!

 
[Image description: Plastic bottles and other plastic trash in a yellow waste bin.] Credit & copyright: Hyena, Wikimedia Commons. This work has been released into the public domain by its author, Hyena. This applies worldwide.

Who would have ever thought that the prey would have something to thank the predators for? Researchers at Wageningen University & Research in the Netherlands have published a paper in Science Advances showing how predators drive the evolution of their prey. The experiment involved guppies, chosen for their quick reproduction cycles, living in an enclosed environment. Researchers selectively introduced and removed predators from the controlled environment and observed how the guppies adapted. As expected, the presence of predators influenced the natural selection within the guppy population, but to a surprising degree. Within just three generations, the guppies responded by changing both their rate of reproduction and their body size. More specifically, the female guppies began reproducing earlier in life and produced more offspring. Meanwhile, the males’ bodies changed to improve their agility with shorter tails and smaller reproductive organs. Overall, the guppies grew smaller with each generation. The experiment influenced the evolution of the guppies purely with predation pressure, meaning that there was no sexual selection taking place at all. In the wild, female guppies are more likely to breed with colorful males, but such features were not affected during the experiment. The researchers were therefore able to determine exactly which physical features evolved due to predation pressure, and which ones were the result of other factors. While we already knew that predation is a major driver of evolution, this experiment surprised researchers by showing just how quickly it can cause change. Those are some speedy guppies.

[Image description: A colorful guppy fish against green aquatic plants.] Credit & copyright: 5snake5, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
 

These humped heroes sure know how to beat the heat. As a heat dome scorches much of the U.S. this week, it’s a good time to learn about an animal who wouldn’t mind these temperatures at all. Camels are Earth’s largest desert-dwelling animals. While most desert animals evolved to be small so that they could escape the scorching heat by burrowing or seeking out slivers of shade, camels took a different approach. They evolved large, portable energy-conservation tanks in the form of humps.
 
Contrary to childhood legends, camels’ humps don’t actually contain water. Rather, they’re full of fat, from which their bodies draw energy throughout long treks in the heat. This allows them to eat and drink very little while on the move. In fact, camels can survive around a week without water and several months without food, even while walking up to 20 miles a day in scorching temperatures.
 
Camels are part of a group of animals called ungulates, most of which are hooved. Camels, however, have soft foot pads with two large, hard toenails. Though there are seven species in the family Camelidae, only three are commonly called camels: the dromedary camel, Bactrian camel, and wild Bactrian camel. Dromedaries have just one hump while bactrains have two, but that’s not the most important difference between them. Dromedaries are a completely domesticated species, while some bactrian camels still remain in the wild, living mostly in northwestern China and the Gobi Desert in southwest Mongolia. While bactrains are critically endangered, dromedaries are fairly common, making up about 94 percent of Earth’s camel population.
 
So, why domesticate camels? For people living near deserts, it makes perfect sense. Dromedary camels can comfortably carry up to 330 pounds over long distances, and even more during short trips. Humans can comfortably ride them, which makes them invaluable for crossing areas where roads are scarce. Camels can also be used for milk and even meat, making them one of the most versatile domesticated animals around. That’s not to say that all dromedaries live a sheltered life. Central Australia is home to a sizable population of feral dromedaries, whose ancestors were brought to Australia by 19th century European settlers. As an invasive species, they’ve caused some harm to local wildlife by eating native plants and drinking valuable water that native animals need to survive. A hunting program allows for a certain number of these feral camels to be killed each year, but their population remains fairly large. Some dromedaries are just determined to walk on the wild side.

 
[Image description: A dromedary camel walking on a road beside a wooden fence and green trees.] Credit & copyright: A1000, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.

It seems they’re turning red meat into read meat. According to a paper published in Scientific Reports, scientists at São Paulo State University (UNESP) have identified genetic markers that are associated with higher quality meat in cows. Current, conventional practices can only do so much when it comes to producing quality beef. At the end of the day, and all else being equal, livestock producers rely on the breed of cattle to do the heavy lifting. Even then, quality can be inconsistent between individuals thanks to phenotypic variability. But the researchers at UNESP appear to have cracked the code while working with Nelore cattle, a breed of zebu which make up around 80 percent of the cattle raised for meat in Brazil. By collecting samples from 6,910 Nelore carcasses after slaughter and grading, they managed to identify specific markers that are responsible for marbling (the amount of intramuscular fat), subcutaneous fat thickness, and muscle development. One particularly interesting discovery involved a gene responsible for heat shock proteins, which can influence meat tenderness by affecting fiber degradation after slaughter. The tenderness of meat can vary greatly between individuals depending on how much the gene is expressed. While similar efforts have been made before, including by the researchers at UNESP, this study was uniquely able to produce results by taking a more comprehensive look at the biology of individual animals. As the first author of the study, Gabriela Frezarim, explained, "The group had already made significant progress using different 'omics' [genomics, transcriptomics, and proteomics] approaches, but it became increasingly clear that no single technique is sufficient to understand the complexity of the biological systems that control variation in meat and carcass quality.” It’s like herding scientific disciplines together.

[Image description: A brown-and-black zebu cow walking on grass.] Credit & copyright: Mammalwatcher, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
 

Make way for the only bugs that can be mistaken for stars. When fireflies light up the summer sky, it’s at least as impressive as a celestial lightshow. However, it seems that fewer fireflies (or lightning bugs, as they’re sometimes called) are showing up each year. Luckily, there are things that everyday people can do to help dwindling firefly populations.
 
Fireflies are soft-bodied beetles in the family Lampyridae. Although there are thousands of firefly species (around 2,400) the most common species in the U.S. is Photinus pyralis. These small beetles grow to be around .7 inches and feature bright orange heads atop black bodies. At the end of their abdomen is a whitish-yellow area from which the fireflies emit light. This is the firefly’s lantern, an organ in which the insect’s famous light-emitting chemical reaction takes place. The reaction relies on an energy-carrying molecule called adenosine triphosphate (ATP) which helps a chemical compound called luciferin create light when it reacts with oxygen and the enzyme luciferase.
 
Contrary to popular belief, both male and female fireflies light up, but only the males of the Photinus pyralis species do so while flying. In fact, the males’ characteristic flight patterns, in which they swoop low to the ground then light up as they fly upwards, have earned them the nickname “big dipper fireflies.” Meanwhile, females land on tree trunks or other vegetation and signal to males if they’re ready to mate.
 
Bioluminescent animals, which emit light via biological processes, are common in the ocean, but they’re fairly rare on land. Fireflies are by far the most frequently-encountered bioluminescent animals in the U.S., which has naturally made them beloved. Unfortunately, 18 species are now considered endangered in North America. While Photinus pyralis isn’t yet considered threatened, anecdotal reports seem to show that fewer of them are being seen year by year. Climate change plays a role, but much of the trouble also has to do with general human development, especially light pollution. While U.S. neighborhoods (where people commonly saw fireflies) used to be dark at night, the advent of energy-efficient streetlights and the popularity of solar-powered garden lights have left fireflies without enough darkness to put on a proper display. Like all beetles, fireflies go through a larval stage as part of their development. Firefly larvae are wingless, which leaves them more vulnerable to household herbicides and pesticides. Fireflies lay their eggs in leaf litter, which is often bagged up and thrown out in yards, dooming the eggs.
 
The good news is that there’s plenty we can do to usher fireflies back to U.S. neighborhoods. Reducing light pollution can be accomplished by simply ceasing to use garden lights and turning other lights off at night. Using fewer pesticides and leaving leaves alone in the fall are other, easy ways to help fireflies. Hey, less yardwork sounds pretty enlightened to us.

 
[Image description: A firefly on a green leaf.] Credit & copyright: Bruce Hallman/USFWS. Public Domain Mark 1.0 Universal.

They may be small, but they’re a big deal. Scientists at the Rosenstiel School of Marine, Atmospheric, and Earth Science have published a study in the journal Nature npj Viruses, detailing a slew of newly-discovered giant viruses that shape ocean life. While the ocean is vast and home to some of Earth’s largest creatures, the base of the food web still consists of its smallest denizens, including algae, amoeba, and flagellates (microscopic organisms defined by their single, whip-like tail that is used for movement). These organisms are greatly affected by giant viruses, which, as their name implies, are much larger than most viruses, with some even being larger than bacteria. Such viruses can cause havoc in the delicate balance of the ocean’s food web. Among other things, they can cause algal blooms, which can be directly harmful to animal and human health.
 
As significant as their ecological role is, giant viruses were poorly understood until recently, and little was known about their genome. To learn more, the researchers pored over existing marine metagenomic datasets and were able to identify 230 novel giant viruses, along with 530 new proteins. Some of these proteins were found to be linked to the viruses’ ability to manipulate the process of photosynthesis in their hosts, possibly explaining how they lead to algal blooms. In fact, figuring out how to deal with algal blooms was one of the motivations for the research. One of the study’s co-authors, Mohammad Moniruzzaman, explained, "By better understanding the diversity and role of giant viruses in the ocean and how they interact with algae and other ocean microbes, we can predict and possibly manage harmful algal blooms, which are human health hazards in Florida as well as all over the world.” Even some of Earth’s biggest problems are caused by small things.

[Image description: A digital illustration of green viruses against a blue background.] Credit & copyright: Author-created illustration. Public Domain.
 

These wild equines have got a bit of a mean streak, plus a whole lot of stripes! The rescue of an escaped pet zebra in Tennessee has recently gone viral after the animal was airlifted to safety, but very few people will ever own a zebra. That might seem odd, given that their close cousins, horses, are some of humanity’s most prized domesticated animals. There are plenty of good reasons why zebras have never been domesticated, though, and why you’ll (hopefully) never see a person riding one.
 
Zebras are part of the genus Equus, along with horses and wild asses. These three groups represent the only living members of the family Equidae, and zebras are the only ones that have never been domesticated by humans. There are three species of zebras, and all of them live in grasslands, shrublands, and savannahs across eastern and southern Africa. There, they live in herds of up to 20 individuals, eating grasses and small, shrubby plants. Their beautiful black-and-white stripes make them stand out to human eyes, but they also break up their individual silhouettes, so that predators have a harder time pinpointing a single zebra. That’s important, since zebras have to survive amongst some of the most fearsome predators on the planet, including lions, hyenas, crocodiles, and wild dogs, among others. When confronted by predators, zebras will group close together to deter them. When that isn’t enough, however, zebras can and will fight, lashing out with powerful kicks and bites.
 
Unfortunately for humans, the behavioral adaptations that make zebras so perfectly suited for their African home are exactly the ones that make them impossible to domesticate. Zebras are aggressive enough to fend off lions, so would-be-zebra-riders don’t stand much of a chance. Zebras have a strong “ducking” instinct, which helps them protect their throats from predators in the wild. In a domesticated setting, it means that zebras are all but impossible to lasso or leash, and that they struggle against bridles. Zebras also don’t have a hierarchical herd structure, like wild horses do. This means that there are no leaders in wild zebra herds, which would make it pretty difficult for a zebra to accept a human as its leader. All in all, while zebras might look a bit like horses, they’re really a different stripe of creature entirely.

 
[Image description: A zebra walking through grass and brush.] Credit & copyright: Alvinategyeka, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.

These flies are about to get buzzed…for the greater good. According to a paper published in The Journal of Neuroscience, researchers at the University of Utah have genetically modified fruit flies so that they can become addicted to cocaine. It sounds shocking, but there's a good reason for it: the researchers are trying to figure out which genes are most responsible for addiction risk in humans. These genetically-modified flies will be exposed to cocaine and given the ability to self-administer, and the researchers hope to use the model of addiction disorder in fruit flies to uncover the biological foundations behind addiction in general. Getting flies to accept cocaine, however, was no mean feat. Insects like flies are naturally averse to cocaine since it is a plant toxin, and flies detect toxins through taste receptors on their legs. Researchers had to find a way to disable those receptors so that they would accept sugarwater laced with cocaine instead of flying away. Once that hurdle was overcome, the flies took readily to the narcotic, and they reacted in much the same way humans do. As lead author Adrian Rothenfluh confirmed, "At low doses, they start running around, just like people. At very high doses, they get incapacitated, which is also true in people." While the method sounds a little odd, the research might prove invaluable to the millions of people who suffer from addiction. Cocaine is considered highly addictive, with 15 percent of those who try it becoming addicted within 10 years. If only human beings could be so naturally averse to what hurts them!

[Image description: A fruit fly with red eyes under a microscope.] Credit & copyright: Asmawati24, Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.