Creature: Scavenger

Organisms that feed on dead or decaying organic matter, playing a crucial role in nutrient recycling and ecosystem health.

Featured Creature: Wolverine

Zoo Hluboka (CC via Wikimedia Commons)

What creature is considered a trickster in Indigenous culture, and the namesake for one of the most popular superheroes of all time?

The Wolverine! (Gulo gulo)

Featured Creature: Wolverine
Zoo Hluboka (CC via Wikimedia Commons)

When I was in fourth grade, we were assigned creatures about which to write essays. I was given the wolverine. Back then, the only thing I knew about the wolverine was that it was the name of a superhero in X-Men. But as I researched more about the animal, I learned that the wolverine is just as cool as a superhero!

Wolverines are the largest animal of the Mustelidae family, which includes weasels, badgers, and sea otters, among others. Wolverines are mostly found in cold remote climates, as in northern Canada, Russia, and Siberia. There have also been reports of wolverines in Ukraine and Latvia. If you’ve ever seen a wolverine in the United States, you should consider yourself lucky! Wolverines have only rarely been spotted in North America.

If you ever encounter a wolverine in the wild, think twice before getting close!

TEldar (CC via Wikimedia Commons)

Wolverines—The Trickster Animal

Wolverines can be found in various oral histories and mythologies from many Algonquian tribes, as well as the Innu people of Quebec. Even though several different cultures mention the wolverine, they all categorize the animal with the same label—a “trickster.” The Innu believe that the wolverine created the whole world, gathering up all the animals into a boat like Noah’s Ark. While the Innu sees the wolverine as more of a funny trickster, other tribes like the Mi’kmaq and the Passamaquoddy see the wolverine as more dangerous. They view the animal as a thief, and a companion to the wolf. The Dene tribe also views the wolverine as a trickster, but one that can shapeshift into other creatures.

So, why do all these tribes classify the wolverine as a trickster? Certainly the trickster is a much studied aspect of cultures worldwide, but I’d like to offer my personal take.

Wolverines are around the size of a medium dog. They are carnivorous scavengers, which means they eat animals who are already dead. Because of their size and dining habits, you might assume that they’re not as dangerous as other carnivores. However, wolverines are known to kill animals much larger than themselves, including wolves, deer, and moose. They also have pungent anal scent glands, which are used for marking territory and attracting mates. This has led to them getting the nickname “skunk bear” or “nasty cat.”

This is where my theory comes from: Imagine you’re walking outside, and you see a dog. You’ve never seen a dog that looks like this before, but it’s small and cute, so you go to pet it. But before you do, a deer walks by, and the dog attacks it. You watch this dog kill a deer about five times its size and start feasting on its body. If that wasn’t enough, the dog just absolutely reeks!

I imagine that the Indigenous tribes who first interacted with the wolverine were shocked by its behavior and labeled the animal as a trickster from then on.

In the Words of Monty Python, “Bring Out Your Dead!”

VZavadil (CC via Wikimedia Commons)

Though their ability to hunt down prey is impressive, it is not the wolverine’s main source of food. Wolverines are scavengers, relying heavily on the carcasses of other animals (carrion), including winter-killed elk, moose calves lost to predators, and avalanche victims. Wolverines have a keen sense of smell that enables them to detect a buried carcass under several feet of snow.

It’s not the prettiest job title, but wolverines are the garbage collectors, sanitation crew, and nutrient recyclers of some of the planet’s coldest, most remote ecosystems. Their remote existence supports ecosystems that other creatures barely reach.

Carcasses attract pathogens and parasites that can spread to other wildlife, and left alone, their frozen bodies would take a long time to decompose in frozen ground. Not only do wolverines reduce the spread of disease, their breakdown of carcasses returns nitrogen, phosphorus, and other nutrients to the soil, feeding everything from microbes to the plants on which herbivores depend.

Wolverines store surplus meat in snow “freezers,” prepositioning food resources across their landscape. Researchers believe this behavior is tied to their denning needs.

Snow-Dependent Species Trying to Survive in a Warming World

Wolverines are adapted to the cold and depend on snowpacks to reproduce and store food. Researchers who mapped 562 wolverine den sites across North America and Scandinavia found that nearly all of them (98%) exist in areas where snow cover persists into mid-May. Female wolverines dig their dens deep into the snowpack, insulating their kits from extreme cold and predators. Snow is essential for their reproduction and survival.

Our warming climate is causing a rapid decline of the spring snowpacks that wolverines need to den, and store their food. Current population numbers reflect this impact. Biologists estimate that fewer than 300 wolverines remain across the entire contiguous United States, with a breeding population of fewer than 50 individuals. In November 2023, the U.S. Fish and Wildlife Service officially listed the North American wolverine as a threatened species under the Endangered Species Act, citing climate-driven habitat loss and fragmentation as the primary long-term threat, with trapping and winter recreation disturbance near den sites supplemental factors.

Because wolverines need such vast, connected, undisturbed territory and such specific snow conditions, they are considered indicator species. They represent a living gauge of healthy, high-elevation snowpack ecosystems. When they are able to survive, it’s a good sign that the underlying systems are holding together. Loss of wolverine populations are an early indicator that the ground systems are unravelling.

So, About That Superhero…

If you were like me in the 4th grade, the first time you heard the name “wolverine” was from the Marvel comic book/movie series X-Men. Of course, the animal came before the superhero, which led me to thinking: Why was Wolverine named after the animal?

First, if you know anything about the character Wolverine, it’s that he has retractable claws. This is, in fact, the opposite when it comes to the animal. Though they are sharp enough to kill their prey, the wolverine’s claws are non-retractable. Their claws are always out, which helps them not just with hunting, but also for climbing and digging.

Even though Wolverine’s claws are not anatomically identical, everything else about his fighting style is reminiscent of the wolverine. During cage matches, most opponents were bigger than he was, just like a wolverine with its predators. Yet size did not hinder the strength of either one. Wolverine was able to best his enemies with strength, fighting tactics, and all-around ferocity, just as the wolverine does.

JSpaedtke (CC via Wikimedia Commons)

Melanie Davis-Kay is a soon-to-be graduate from Lesley College. She was a former volunteer at The Discovery Room inside the Museum of Science. She lives in Arlington, MA.

Sources

Featured Creature: Greenland Shark

What creature has a lifespan of over 250 years and catches prey by suction?

Featured Creature: Greenland Shark
Image: A Greenland shark; Wikimedia user Zlois (CC0 via Wikimedia) 

The Greenland Shark (Somniosus microcephalus) is one of the oldest and largest sharks in the world. It is the biggest of its superorder, Squalomorphii (one of the two groups of sharks). They can get up to 21 feet and 2,255 pounds, and have an average lifespan of 272 years. The oldest recorded Greenland Shark was almost 400 years old; that shark was alive during the Scientific Revolution! When I first came across these sharks and their longevity, I was fascinated. There are so many interesting things about this creature, so let’s take a look!

Amazing Adaptations

Unlike most other sharks, Greenland Sharks like cold, deep water, and are usually found near the Arctic or Atlantic Oceans. Greenland Sharks have special adaptations that help them thrive, and allow them to survive near-freezing water temperatures and high water pressure. 

For one, they’re big animals, and larger animals tend to have slower metabolisms and therefore age slower. Their slow metabolisms also mean they move almost lethargically. This gives them part of their scientific name, Somniosus microcephalus; “Somniosus” comes from “somnum”, the latin word for sleep! That’s why they’re also called sleeper sharks. 

If they’re so slow, how do they catch prey so fast? Greenland Sharks are known to eat seals, fish, and other fast aquatic animals, but they can only reach a maximum of around 1.6 miles per hour (one of the slowest animals of their size!). They primarily catch food by ambushing prey while they’re asleep, and by targeting injured animals. Since there’s little to no light at the depths these sharks are found at, and they’re usually dark colors, they can sneak up and surprise other creatures. They also have a special method of actually “grabbing” their targets. They open their mouths fast, creating a suction force that draws water (and the animal) into their large mouths, allowing them to swallow some prey whole. 

Image: The open mouth of a dead Greenland Shark, showing off the teeth; Audun Eriksen (CC BY-NC 4.0 via iNaturalist)

Another example of Greenland Sharks’ adaptations to their environment is the fact that they have specific chemical compounds in their bodies that help them in different ways. The two common ones are urea and TMAO (trimethylamine N-oxide). Since these sharks are constantly surrounded by saltwater at high pressure, lots of urea in their body helps the shark’s cells keep their shape. This is why they’re classified as osmoconformers: they have high concentrations of urea in their body to match high concentrations of salt in the outside water, keeping a balance. Also, both urea and TMAO help the shark be less dense, allowing it to float better. 

Urea does also have some negative side effects: too much of it can destabilize enzymes within the shark, hurting them and keeping proteins in their body from functioning correctly. TMAO counteracts this, stabilizing proteins even when there’s a lot of urea. This process allows Greenland Sharks to survive without trouble in the Arctic Ocean. 

While these chemicals are helpful to sharks, they’re absolutely not for humans. TMAO in particular is extremely toxic to mammals, and can lead to extreme sickness or death. People do eat them, though! These sharks are a delicacy in some places: Hákarl, cubes of fermented Greenland Shark meat, is the national dish of Iceland. Because of the TMAO and urea, the meat has to be dried for weeks or months, and fermented in a certain way so it becomes safe for human consumption.

Image: Hákarl (fermented Greenland Shark meat, cubed); Wikimedia user Holapaco77 (CC BY 2.0 via Wikimedia)

Deep water usually doesn’t get much light, so these sharks adapted by also evolving other ways to “see”. They have an incredible sense of smell and rely heavily on it for navigation. They also have the ability to sense electric fields through special gel-filled pores all over their snout and face! This sixth sense lets them detect small movements and even heartbeats, allowing them to navigate both on a small scale (their immediate surroundings) and a large scale (Earth’s magnetic field). 

In fact, their other senses are so well-developed that they don’t need sight at all. Many Greenland Sharks’ eyes become infected by a copepod called Ommatokoita elongata. This parasitic crustacean gets permanently attached to the corneas of the shark, injuring their eyes and sometimes rendering them completely blind (though the sharks don’t notice or care!). These creatures can sometimes have bioluminescence, making the shark look as if it has glowing eyes. It’s been theorized that, in the darkness of the water, this spot of light may help the shark attract prey.

Image: A Greenland Shark, eyes infected with Ommatokoita elongata parasites; Wikimedia user Hemming1952 (CC BY-SA 4.0 via Wikimedia)

Important interactions

Greenland Sharks have been around for a long time, and lots of different people have interacted with them in various ways. Because of their niche habitat range, accidental encounters are rare, and there haven’t been any recorded human attacks. These sharks aren’t aggressive (like most sharks, even though they get a bad reputation). Since they’ve been around for over a million years, different cultures have had different peaceful interactions with Greenland Sharks. 

Sightings of these sharks may be behind the legends of the Loch Ness monster (although other creatures might contribute, too). There are also Inuit legends involving these sharks. Since they have such a high urea content, they smell like ammonia, or urine. One legend involves the sea goddess Sedna throwing a urine-soaked rag into the ocean, where it transformed into the first shark, a Greenland Shark. The nordic dish hákarl originally got so famous because when the meat isn’t fully fermented, it’s mostly non-toxic but has inebriating effects, which was thought to help people connect to and communicate with Sedna.

Image: A figurine of Sedna from the National Museum of Finland; Wikimedia user Sailko (CC BY 3.0 via Wikimedia)

These sharks have had plenty of negative interactions with people, too. They used to be purposely hunted for the production of certain oils. This doesn’t happen as much anymore, but they are still a frequent bycatch species. This means that they’re often accidentally captured or killed in the process of trying to catch some other animal. Modern fishing methods make bycatch more and more common, and this results in overhunting of many fish species around the world. Trawls are one of the most problematic examples of this. 

A trawl net is a large, basket-like net that’s weighted to drag along the sea floor. Boats pull the nets along the ground at high speeds, and any animal in the way gets scooped up and trapped. This is terrible for sea life; imagine if you were a little sea creature at the bottom of the ocean, and out of nowhere an almost-invisible net grabs and traps you along with everyone else nearby. Entire populations of animals get captured in these nets, and most of them end up getting thrown away! Bottom feeders, or species that spend their time on the ocean floor (like Greenland Sharks), are typically deemed undesirable for selling. The targeted fish species only end up being a tiny fraction of the total catch, and the rest often gets discarded. 

Image: Model representation of a trawl fishing technique; Andreas Praefcke (CC0 via Wikimedia)

Not only is this fishing method inefficient and wasteful, the nets damage homes of ocean animals by breaking or smashing everything in their path. Annually, around 3,500 Greenland Sharks are caught and killed as bycatch. Fishing methods like these have resulted in a decline in Greenland Shark populations, as well as many other aquatic animals. 

Image: A mountain of dead dogfish being emptied from a trawl net; Wikimedia user Citron (CC0 via Wikimedia)

Other factors relate to the well-being of Greenland Sharks, and global warming is a big one. Since these sharks love cold water, they usually stay around the Arctic circle. Global warming is making this water a little warmer than it used to be, and a lot of the sea ice is melting. 

Greenland Sharks have extremely long lifespans, but they also have low fertility rates and long gestation periods (how long it takes a baby to develop). Greenland Sharks have gestation periods of around 8 to 18 years. This means that it takes them a long time to replace population members. If too many die at once, baby sharks might not be born fast enough to save the population.

All of these factors influence the rarity and vulnerability of these sharks. 

The IUCN Red List is a list that keeps track of vulnerable or endangered species. In 2020, Greenland Sharks got reclassified from near threatened to vulnerable. Unfortunately, since they have such a slow recovery time, their status will probably continue to get worse. This is bad news for a very strong reason: Greenland Sharks are incredibly important to their ecosystems. 

As apex predators, they eat pretty much everything, including fishes and seals. They’re able to do this by ambushing prey, as described above. This helps them keep those populations in check by controlling how many of their prey species there are. If Greenland Sharks went extinct today, those other species would multiply. They would quickly take over ecosystems, destabilizing them, interrupting food chains, and overall harming everyone. Greenland Sharks prevent this by acting as a neutralizing force on population sizes of other fish. These sharks are important for maintaining balance in their environments. 

Image: A Greenland Shark caught as trawl bycatch; Claude Nozères (CC BY-NC 4.0 via iNaturalist) 

Greenland Sharks are scavengers; they eat carrion and other dead matter. They can eat large carcasses of animals that fall to the bottom of the oceans (like whales; have you ever heard of a whalefall?). Greenland Sharks actually have very unique, specialized teeth to let them do this; their upper teeth are small, thin, and pointy. Their lower teeth are chunkier with complex shapes that point away from the top teeth. This lets them tear off large chunks of meat when they roll their jaw. Teeth like this are another incredible example of Greenland Sharks’ specialized evolution! Eating already-dead animals lets them get energy and nutrients from other sources, “recycling” it and putting it back into the ecosystem. 

Overall, Greenland Sharks are very important to their environments, and their removal would have disastrous effects on surrounding sea life.

Image: A dead Greenland Shark; Claude Nozères (CC BY-NC 4.0 via iNaturalist)

To me, these weird, fascinating sharks are incredible. They have strange and unique adaptations that help them survive their extreme environments, and they’re important to those environments because of their interactions with other species. Because of the specificity of their Arctic circle deepwater habitat, they’re relatively poorly studied. There isn’t that much recorded information on them; we still have a lot of unanswered questions. After learning more about them, I’m personally interested in how they’re able to survive for centuries (some genetic research implies it’s related to transposons, or “jumping genes” that can move around the chromosome!). 

And while I tried, there’s also a lot about these sharks I didn’t mention. You can read more about their genetics here, about their longevity here, and about the harms of overfishing and trawling here.

Anya Reddy is a high school student at Blue Valley North. She loves biology and biochemistry, as well as entomology, ecology, and environmental science in general. Some of Anya’s non-science passions include archery and all kinds of 2D and 3D art. She enjoys learning about all kinds of organisms and how they connect and interact with others in their environment; she hopes to use writing to help share fascinating details about them, helping others like the weird and interesting organisms she loves.

Dig Deeper

Featured Creature: Bearded Vulture

What handsome creature dyes its feathers and almost exclusively eats bones?

The Bearded Vulture! (Gypaetus barbatus)

Photo by Marco Pagano on Unsplash

The bearded vulture (Gypaetus Barbatus) is a bird of prey known by many names including lammergeier, quebrantahuesos, boanbrüchl, and ossifrage.

The origin of these monikers come from the bird’s unique diet – bones. While most vultures pick off the meat on a carcass, the bearded vulture prefers to consume the skeleton itself. Over 80% of their diet consists solely of bones.

Weighing in at about 16 pounds and equipped with a wingspan of over 9 feet, bearded vultures are among the top ten largest birds of prey in the world. They use their substantial size to hoist the bone of their choice from the skeleton to the sky. They fly high enough to drop it onto a clifftop or boulder to break the bone into smaller, bite-sized pieces which they then swallow whole.

What makes these birds capable of digesting bone is the strength of their stomach acid. Bearded vultures have a stomach acid of nearly zero pH. This extreme acidity dissolves bone within 24 hours. To put this in perspective, humans have a stomach acid pH of about 2 while battery acid has a pH of about 0.8. Bearded vultures are the only carnivores capable of completely digesting bone.

Photo by Mr Wildclicks from Pexels

Striking Appearance

Bearded vultures appear different from most other vultures due to the lack of a bald head. Most vultures are known for having no feathers around their head and neck which helps them remain clean when scavenging carrion. Bearded vultures, because of their chosen bone-based diet, do not need this adaptation, and sport a feathered head. Adults have white feathers along their body, chest, and face while their wings are dark brown. Black tufts protrude from their chin which gives them their modern namesake of bearded vulture. 

Bearded vultures have large, glacier-white eyes that help them spot carcasses from the sky. As Old World vultures, their sense of smell is not advanced and they rely primarily on their eyesight when scavenging. When threatened or excited, the scleral ring around their eyes turns a bright red.

Bearded vultures have a unique propensity for the color red, so much so that they dye their white feathers a rusty vermilion. These birds will seek iron-oxide rich pools of muddy water or dust and bathe in it to color themselves a red-orange hue. Researchers are unsure of why they do this. Some posit that it is a sign of status – the redder the bird, the higher the seniority. Others believe the iron-oxide coloring helps prevent infections when breeding. Whatever the reason, bearded vultures paint themselves into a real-life phoenix. 

Photo by David Ruh from Pexels

Habitat and Ecological Role

Bearded vultures call the mountainous regions of Eurasia, East Africa, and parts of the Middle East their home. They prefer to live in areas that grant them the best visibility such as remote mountain ranges, steppes, canyons, and alpine valleys.

These birds tend to fly at high altitudes of about 6,500 feet above sea level. They utilize updrafts to ride the air currents which helps them conserve energy and glide for many miles.

In the early 1900s bearded vultures were hunted in Europe due to a false myth that they supposedly preyed upon children and livestock. The population in this area declined and is still recovering today. Currently, humans are the greatest threat to bearded vultures as habitat loss and poisoning endanger the remaining populations. The species is listed as near threatened by the IUCN. 

Bearded vultures are an incredibly important species for the ecosystem because they act as nature’s garbage disposal. They help clean the environment of carcasses and diseases which keeps other species healthy.

Soaring away for now,
Joely

Joely Hart is a wildlife enthusiast writing to inspire curiosity about Earth’s creatures. She holds a Bachelor’s degree in creative writing from the University of Central Florida and has a special interest in obscure, lesser-known species.

Sources and Further Reading:
https://www.beardedvulture.ch/beardedvulture/biology
https://faunafocus.com/portfolio/bearded-vulture
https://safarisafricana.com/largest-birds-of-prey
https://factanimal.com/bearded-vulture/
https://digital.csic.es/bitstream/10261/64406/4/functilife.pdf
https://pubmed.ncbi.nlm.nih.gov/36596809

Featured Creature: Crow

Carrion crow (Corvus corone) black bird portrait of head and looking at camera. Wildlife in nature. Netherlands

What common bird possesses an uncommon intelligence, including diversified communication, excellent memory, and a talent for mathematics? 

The Crow! (Corvus)

Image by Kev from Pixabay

Crows, members of the Corvus genus, stand out as some of the most intelligent and adaptable birds on the planet. These corvids include over 40 species, such as the American crow, hooded crow, and fish crow, and they inhabit diverse habitats ranging from dense forests to urban landscapes. 

Known for their resourcefulness and problem-solving skills, crows have captivated scientists and observers alike with their remarkable behaviors. Crows continue to push the boundaries of how we understand animal intelligence, with recent studies on their tool use, awareness, and relationship to complex concepts gaining them well-deserved recognition and a place in the conservation conversation. 

Image by Wolfgang Heubeck from Pixabay

Crows are a fairly common sight in many parts of the world, with recognizable shiny black feathers and a familiar ‘caw.’ They are ground foragers with an incredibly diverse diet, ranging from insects and fruits to small animals and human food scraps. They tend to be associated with scavenging but are true omnivores, and can benefit soils and ecosystems by helping keep insect populations from surging out of balance. In urban settings, they are involved in flock feeding on human food scraps and garbage, and this adaptability to human environments means certain (though not all) species of crow maintain strong population numbers in the face of decreased access to natural habitat.

Communication and Complexity

While the crow ‘caw’ may seem like a simple call recognizable to many people, crow vocalization turns out to be quite differentiated. It has been discovered that among crows, groups form ‘dialects’ based on region. They also possess remarkable vocal mimicry skills, allowing them to imitate the sounds of other birds, animals, and even human speech. All of this allows the crow to engage in communication, social bonding, and strategic goals of deception and resource acquisition.

These crafty corvids possess a level of intelligence comparable to great apes and human children, allowing them to solve complex problems and even make and use tools. For instance, the New Caledonian crow, widely regarded as the most intelligent species among the corvid family, creates hooks and skewers from twigs to extract insects from crevices, showcasing their ingenuity. Researchers have studied crows’ usage of tools and observed that these birds will not only use pre-made tools or create simple combinations of tools in pursuit of their goal, but create multi-part composite tools, a behavior observed in only a few primates. 

Famously, Aesop’s fables summarized long ago, “A thirsty crow wanted water from a pitcher, so he filled it with pebbles to raise the water level to drink.” Though the story is thousands of years old, these behaviors are still being studied and producing new insight today.

Image by Thanasis Papazacharias from Pixabay

Some of the most fascinating recent inquiries into crow intelligence have probed crows’ sense of self-awareness, long-term gratification, playfulness, and their understanding of complex concepts. As a math lover, one of my favorites among these is a unique phenomenon – conceptualization of ‘zero’. While many animals are able to perform basic counting, zero is generally a trickier beast, one that was absent from many ancient human civilizations’ numerical systems. However, crows are among the very few animals that grasp this number. 

Additionally, crows exhibit impressive memory skills and can recognize individual human faces, reacting differently to perceived threats than to harmless humans. They are even known for ‘holding grudges,’ or conversely, remembering favorable relationships with people for years at a time. The ability to remember and share information within families and flocks may provide them with a significant evolutionary advantage in protecting themselves from harm.

Birds of a Feather Flock Together

In addition to their intelligence and adaptability, crows exhibit fascinating social behaviors. They often engage in cooperative mobbing to fend off predators, perform elaborate aerial displays to attract mates, and maintain strong family bonds by living in cooperative family groups. While adult crows primarily socialize just with their monogamous mate (with whom they pair for life), young crows stay with their parents for the first two years of life, and juvenile crows live in highly social ‘juvenile gangs.’ One theory into crow intelligence suggests that their ingenuity is due to the relatively long period of time young crows spend with their parents and the learning this enables.

Some crows, like American Crows, are also known to flock in large groups in winter months, both foraging for food and roosting together. These roosts can range from a few hundred to up to two million crows, with some roosts forming in the same general area for well over 100 years. Moreover, crows hold “funerals” for deceased members of their community, demonstrating a level of social complexity often overlooked among animals. 

Crows will even form bonds with other animals. Crows in the wild have been observed playing with young wolves, and forming mutual attachments with these other social and intelligent creatures. Of course, there are many stories of the relationships humans have forged with individual crows, forming patterns of exchanging food for gifts or receiving trinkets after showing an injured bird care. One charming crow, Tuck, who has spent his life in a bird sanctuary in Tennessee, shares a moving friendship with his primary human caretaker, and has even become a conservation ambassador:

While many human cultures have depicted crows with respect for their ingenuity, recent trends have given crows a bad rap, primarily for the disturbance they cause to crops (hence the need for ‘scarecrows’). Despite their reputation as pests, though, crows play a crucial role in ecosystems as efficient garden helpers and natural pest controllers. They feast on insect pests like caterpillars and beetles, disperse seeds, and maintain a healthy balance in the garden ecosystem. Some crow species face significant challenges to their survival, such as habitat loss, disease, and predation, and crucial conservation efforts are underway to protect endangered species like the Hawaiian Crow through habitat restoration and captive breeding programs.

Crows have been both feared and revered by humans throughout history, often associated with death, darkness, and supernatural powers. The term “murder of crows” reflects their association with death and darkness in folklore, although alternative names like “horde” or “parliament” better capture their intelligent and social nature without perpetuating negative connotations. And many cultures and people have great respect for the clever crow, with whom we have coexisted for thousands of years. Despite their complex relationship with humans, crows continue to fascinate and inspire awe, challenging our limiting notions of animal behavior. 

For a deeper dive into crows and the insights they share on animal intelligence, check out this fascinating video and the sources below:

May we continue to learn from our animal kin,

Maya

Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

Sources and Further Reading:
https://www.iflscience.com/crows-once-again-prove-their-intelligence-by-showing-that-they-understand-zero-60069
https://bigthink.com/neuropsych/crows-higher-intelligence/
https://arstechnica.com/science/2023/12/what-happens-in-a-crows-brain-when-it-uses-tools/
https://www.allaboutbirds.org/guide/American_Crow/overview
https://www.trvst.world/biodiversity/crow-facts/
https://www.audubon.org/news/10-fun-facts-about-american-crow
https://www.audubon.org/news/a-funeral-crows
https://www.npr.org/2020/10/23/927088859/crows-are-they-scary-or-just-super-smart

Featured Creature: Pill Bugs

Image Credit: Franco Folini on Wikimedia Commons

What creature has gills but doesn’t live in water, has a pouch for their young but isn’t a marsupial and has blue blood?

Pill Bugs! (Armadillidiidae)

A glossy, dark grey pill bug with a segmented, armor-plated back walking across sandy, pebbly ground, its short legs and antennae visible at the front
Image Credit: Kiloueka on Wikimedia Commons

Turn over a rock and you’ll likely see “armadillos” that aren’t armadillos, or anything else you’d expect.

The Roly-Poly: Sort of a Rock Lobster

The pill bug, as it is known, has more aliases than James Bond. Depending on where you live, you may know them as potato bugs, roly-polies, doodlebugs, woodlice, or something more exotic like chiggy pigs or bench biters. They are unique creatures distinguished by their ability to form into a ball—a process known as conglobation—as a defense against predators (and small children).

Conglobation as a defense isn’t entirely unique. It is shared with certain wasps, millipedes, and other animals. But for the pill bug, it is a defining characteristic, much like it is for the armadillo. This shared behavior, in fact, and a few similarities in appearance, prompted scientists to assign pill bugs to two families and name them Armadillidae and Armadillidiidae, and leads some people to refer to them as “armadillo bugs.”

Of course, you are now thinking, armadillos are mammals, and these are bugs of some sort. Why are you going on about armadillos?

But where you might assume that, as bugs, they might be insects, like the beetle, or arachnids, or something else known for crawling around in the dirt, your assumption would be incorrect. These are actually crustaceans, like crabs, or crayfish, or krill. They are crustaceans who live out of the water, and would more fittingly be called “dirt shrimp,” if I wrote the dictionary.

Featured Creature: Pill Bugs
Image Credit: Franco Folini on Wikimedia Commons

The Rather Odd Physiology of the Dirt Shrimp

Being related to so many aquatic creatures has given the pill bug a rather unique feature for something that lives on land: gills. They breathe through gills that cannot function underwater but allow them to absorb air in damp environments. The environment must contain moisture, though, because if they dry out, they will die. As a result, they are largely nocturnal and stay under rocks where the soil stays cool and wet.

Conglobation can occur thanks to a segmented body with overlapping plates, called tergites, that contract inwards when the pill bug feels threatened. On the underside, these overlapping plates create a pouch that mothers use to carry their young, carrying a hundred to two hundred at a time, holding first the eggs and then the young for several days after they hatch. This pouch is known as a “marsupium,” named for a similar structure in marsupial mammals. The fact that nobody calls the pill bug a “soil kangaroo” strikes me as a missed opportunity.

A pill bug rolled into a tight, dark grey ball on a wet, brown fallen leaf among bits of soil and leaf litter
Image Credit: Dave Huth from Allegany County, NY, USA on Wikimedia Commons

Pill bugs do not urinate, instead passing ammonia gas directly through their exoskeleton. They also drink with both their mouth and anus, taking in water through their hindquarters via tube-shaped “uropods” which wick water up as needed.

Most pill bugs are born with six pairs of legs, but later grow a seventh, and they have two sets of antennae, only one of which is visible. They have two sets of eyes, as well, one on the side of their heads which provides a detailed view of their surroundings, and another set in the center that is sensitive to light. Since pill bugs are nocturnal, and can dry out in the heat, these eyes can be critical in ensuring they stay in the dark where it’s more likely to be moist.

A Soil-Friendly Diet

The pill bug diet consists mostly of decaying plant matter. Sometimes they are known to eat living plants, which can become a problem for farmers during times of explosive population growth in areas prone to heavy rains or flooding. Sometimes they eat their own waste, which is occasionally necessary for replenishing copper. Their bloodstreams contain a pigment known as hemocyanin, which stores copper and turns the blood blue in much the same way hemoglobin stores iron and turns our blood red.

One of the principal benefits of the pill bug is their ability to rid the soil of heavy metals by taking them in and crystallizing them in their stomachs. As a result, they can be tremendous allies in restoring contaminated ecosystems.

In addition, they are known to remove excess carbon from falling leaves and replenish nutrients while stimulating bacteria, keeping the carbon and nutrient cycles intact. Pill bugs do not bite and do not spread disease, and although in rainy areas they can potentially be a problem, in most parts of the world they do minimal damage to either crops or people.

Dirt Shrimp: Friends or Food?

The internet has a bit of literature on the best ways to cook and eat pill bugs, though it is recommended you do your research first. Reportedly they taste a bit like shrimp, with some saltiness and a nice crunch. Their nutritional value is said to be quite high and, provided you haven’t mistaken the pill bug for another creature, they are safe to eat should you choose.

Elsewhere, a dedicated community around the world likes to keep them as pets. Different lineages, mostly chosen because of coloring, are bred to provide stock to enthusiasts. They are easy to maintain as a pet, only needing a moist habitat and abundant decaying matter on which to feed. This makes them quite useful in lab settings as well, to teach students about biological processes and life cycles.

There are many ways to appreciate these incredible isopods! To learn more about the pill bug in all its forms, check out my sources below.

Let’s make “dirt shrimp” happen,

Mike

Close-up of Smudge, the author’s white dog with tan and dark grey markings and brown eyes, wearing a purple bandana

Mike Conway is a part-time freelance writer who lives with his wife, kids, and dog Smudge (pictured) in Northern Virginia.

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