There are more than 3000 species of snakes on Earth, ranging from the Barbados threadsnake at roughly 10 cm long (about the same as a deck of cards) to the reticulated python at around 6 m in length (almost as tall as an adult male giraffe!). Luckily, only about 600 are venomous, and only around 200 are venomous enough to seriously harm or kill a human.
Despite the existence of hundreds of venoms, nearly all snake venoms fall into one of three categories, depending on how they affect us: neurotoxins, cytotoxins or myotoxins.
Neurotoxins are common to the Elapidae family of snakes, which include cobras, mambas, coral snakes, and copperheads. They work on the nervous system by disrupting the electrical impulses that our nerves and muscles use to function.
Neurotoxins can mess with our neurons in a few different ways. Imagine your neurons like a lamp plugged into an electrical socket. For the lamp to function normally, it should be able to turn on and off at different times. With α-neurotoxins, it’s as if someone put a babyproof cover on the socket, preventing us from plugging our lamp in at all. The result? No light. On the other hand, with dendrotoxins, the lamp is plugged in, but no electricity flows from the socket to our lamp. Again, no light. But with fasciculins, it’s like the lamp’s plug is stuck in the wall. Constantly activated with no off switch, even though we want to go to bed.
Vipers favour the use of cytotoxins—venoms that directly damage cells. Some common types include phospholipases, which disrupt cell walls, and hemotoxins, which affect the circulatory system. Some hemotoxins trigger the destruction of red blood cells, while others affect the clotting factor of blood—either by making blood too clotted and thick to flow or too thin to ever clot and stop external bleeding.
Myotoxins are less common in serpent physiology but are found in certain species of rattlesnakes. They contain basic peptides (chains of amino acids too short to be considered proteins) that directly disrupt the flow of charged molecules our muscles rely on to contract.
With such a wide range of venom types and mechanisms of action, it’s no surprise that nearly every snake species needs a tailor-made antivenom. Luckily, Canada only has four native species of venomous snakes.
Nonetheless, it can be pretty tricky to identify snakes reliably in the wild. So, if you’re ever on the receiving end of a snake bite, seek medical attention immediately! Do not try to catch the snake to bring with you—some help for your doctors in identifying your attacker is not worth a second (or third, or fourth) bite.
A magnitude 9.1 earthquake occurred just off the northeast coast of Japan on March 11th, 2011, at 14:46 local time. The Fukushima Daiichi Nuclear Power Plant, like all nuclear power plants in Japan, features several safety mechanisms meant to mitigate damage to its reactors in such an event. It was built on top of solid bedrock to increase its stability, and all of its reactors featured systems that would automatically shut down—or SCRAM—the fission reactions in response to an earthquake. Luckily, only reactors 1, 2 and 3, out of six total, were in operation on that day and were successfully SCRAMed.
Even with fission stopped, however, the nuclear fuel rods continued to emit decay heat and required cooling to avoid a catastrophe. With connections to the main electrical grid cut off due to earthquake damage, the plant’s emergency backup diesel-run generators kicked in to power the cooling pumps.
Almost exactly one hour after the earthquake, the resulting tsunami struck Fukushima Daiichi with waves 14 metres (46 feet) high. All but one of the diesel generators were disabled by the seawater, and by 19:30, the water level in reactor one had drained below the fuel rod. By the same time, two days later, reactors 1, 2 and 3 had all totally melted down.
In response, over the subsequent days, over 150 000 people were relocated from areas within 40 km of Fukushima Daiichi. Farmers were ordered to facilitate euthanasia for livestock from within the Fukushima exclusion zone, which was estimated to contain 3400 cows, 31 500 pigs, and 630 000 chickens.
Of those 3400 cows, the government euthanized 1500. CNN reports that roughly 1400 were released by farmers to free roam and potentially survive on their own. They are all thought to have starved to death. Three hundred of the remaining animals are unaccounted for, but some farmers who defiantly refused to cull their animals, nor chose to set them free, can account for 200 of the bovines.
Instead, these ranchers—made up almost entirely of cattle breeders—committed to travelling for hours every day into the potentially dangerous Exclusion Zone to continue to feed and care for what some of them refer to as the “cows of hope”.
Where dairy and meat livestock farmers tend to operate larger scale, higher throughput operations, cattle breeders often have small herds and are more attached to individual animals (some even have names). As one farmer told Miki Toda, “The cows are my family. How do I dare kill them?” These animals were spared simply because it was the right thing to do.
These cows and bulls will likely never be used for meat or have their milk collected for consumption. But that doesn’t mean they’re purposeless. Researchers from several universities, including Iwate University, University of Tokyo, Osaka International University, Tokai University, University of Georgia, Rikkyo University and Kitasato University, see the saved herds as an auspicious opportunity for knowledge acquisition.
The scientific research on how radiation affects large mammals is exceedingly sparse. According to Kenji Okada, an associate professor of veterinary medicine from Iwate University, “large mammals are different to bugs and small birds, the genes affected by radiation exposure can repair more easily that it’s hard to see the effects of radiation … We really need to know what levels of radiation have a dangerous effect on large mammals and what levels don’t.”
By studying the cattle exposed to radioactive fallout after the Fukushima Daiichi nuclear disaster, we stand not only to gain retrospective insights into the true effects of radiation on large bovine mammals but to be better prepared if such an event happens again.
The euthanasia of tens of thousands of farm animals represents a massive animal welfare challenge and has a drastic impact on the livelihoods of many. Not only farmers but workers from regulatory agencies, veterinary practices, slaughterhouses, processing plants, feed supply factories, exporters, and anyone else involved in any step of the agricultural process. Nonetheless, it is, of course, warranted if necessary for the safety of consumers of animal products. But was it necessary?
Research on the Fukushima Exclusion Zone herds has been ongoing for nearly a decade now, and while it will take more time to fully see the effects of chronic low-dose radiation exposure, scientists have published preliminary findings and are starting to see trends.
So far, the bovines have not shown any increased rates of cancer. The only abnormal health indicators are white spots that some have developed on their hides. A study of Japanese Black cattle residing on a farm 12 km to the west-northwest of the Fukushima Daiichi nuclear power plant in one of the areas the Japanese government has deemed the “difficult-to-return zone” found no significant increases in DNA damage in the cows. A different study found that horses and cattle fed with radiocesium-contaminated feed showed high radiocesium levels in their meat and milk. However, they found that after just eight weeks of “clean feeding” (feeding with non-contaminated food), “no detectable level of radiocesium was noted in the products (meat or milk) of herbivores that received radiocesium-contaminated feed, followed by non-contaminated feed.”
Much like Chornobyl (the Ukrainian spelling) has become a sanctuary for wild animals despite the residual radioactivity, signs are pointing to a natural “rewilding” of the Fukushima Exclusion Zone. With humans, cars and domestic animals gone, wildlife is able to move into empty urban and suburban environments and thrive. A trail cam study of wild animals around the Exclusion Zone has uncovered “no evidence of population-level impacts in mid- to large-sized mammals or [landfowl] birds.” Wild boars are abundant in the Fukushima region and present another good representative mammal to research. A study of 307 wild boars found no elevation in genetic mutation rates and that a certain amount of boar meat could even be safely consumed by humans.
Although nuclear radiation is a frightening threat, in part due to its invisible nature, evidence seems to be pointing to minimal, if any, health effects for animals exposed to the amount released by the Fukushima Daiichi disaster.
According to a study from the University of Bristol, it’s likely that the situation would be the same for humans had they not been evacuated/relocated. Due to the relatively low-dose nature of the event, the stigma and sometimes severe mental distress experienced by those displaced, as well as losses of life associated directly with relocation and indirectly via increases in alcohol-use disorders and suicide rates, the authors conclude that “relocation was unjustified for the 160,000 people relocated after Fukushima.”
Fairy tales about the origin of zebra stripes are abundant. Some blame sunlight filtered through tree leaves for tanning the zebras hide, others claim the dark lines are scorch marks, acquired after stumbling into fire during a fight with a baboon. Scientists’ ideas of the stripes’ origins are less fanciful, but no less varied. From thermoregulation to signalling to other zebras, a lot of theories have been floated. Fewer theories have been tested, and only recently did support arise for one hypothesis: avoiding fly bites.
Despite their name, horseflies do not limit themselves to horses. There are well over 2000 species of horsefly that target a wide variety of animals, including humans. However, horseflies earned their moniker due both to horses, donkeys and zebras’ extreme prevalence, and the risks these bugs pose equids. Amongst other diseases, horseflies are infection vectors for equine infectious anemia, a retrovirus from the same genus as human immunodeficiency virus (HIV).
Within the Equus family, all 7 extant members have long tails to help flick away pesky insects. But the 3 living species of zebras have an additional tool in their anti-fly arsenal in their fur patterns.
Japanese Black cows painted with white to mimic the zebra coat received 50% fewer deerfly bites compared to those painted with black stripes, or no stripes at all.
Don’t go painting yourself or your animals to avoid deerfly bites just yet though. There is one important specific you need to know first: the critical width. Black and white stripes present a sort of optical illusion to deerflies. Scientists believe that stripes narrower than a critical width (approximately 5 cm) trigger what we call the Wagon-wheel effect. This illusion makes a wheel, propeller or other regularly rotating object appear as if it is spinning backwards. You can see an example of it here.
When faced with black and white stripes, horseflies approached their target faster and failed to decelerate in the final stages of their flights, before contacting zebra surfaces. It’s not just painted mammals that seem to work though. Researchers demonstrated that horseflies will avoid landing on horses wearing a striped blanket, or other surfaces with thin stripes or small (<10 cm in diameter) polka dots.
Charles Darwin postulated that Toucan’s massive beaks might be for sexual selection purposes. Other scientists have theorized that it could be for shows of intimidation, for actual defence or for peeling fruit. Given the beak’s serrated edge, it was once thought that toucans used it to catch and eat fish. We now know that toucans are almost entirely fructivorous, although they do opportunistically eat insects, lizards, and even small birds.
Another thing we now know is that the main function of a toucan’s beak is actually thermoregulation! Just like elephants do with their ears and dogs with their tongues, Toucans rely on their big beaks as heat sinks to maintain their homeostasis and save them from overheating.
Bird beaks across the globe follow a trend called Allen’s Rule, which proposes that the appendages of endotherms (warm-blooded animals) are smaller, relative to body size, in colder climates in order to reduce heat loss. A study of 214 bird species from every continent found strongly significant differences in their beak sizes according to latitude and local environmental temperatures. From penguins to parrots, the species that live in colder places have smaller peckers.
Squirrels, in theory, can survive a fall from an object of any height due to two factors: their size and their mass. A force (such as the force of gravity) is calculated by multiplying mass and acceleration. The acceleration due to gravity on Earth is always roughly 9.81 m/s2, regardless of what object it is acting on. Squirrels are not very heavy—a grey squirrel only weighs about 0.5 kg—meaning that the force acting on a falling squirrel just isn’t that big.
Force = mass*acceleration = 0.5 kg * 9.81 m/s2 = 4.9 N
We measure forces in a unit called “Newtons”, named for Isaac Newton who gave us Newton’s three laws of motion.
Compare this to, for example, a falling 60 kg human, which would be pulled downward with a force of about 489 N. A factor of 100 higher!
On top of being small, squirrels are fluffy and intuitively spread their bodies out when falling. This allows them to experience as much wind resistance as possible, slowing down their rate of descent. Some squirrels even use this fact to glide through the air. While gliding is not the same as flight, we nonetheless call them flying squirrels.
For these two reasons, the terminal velocity (fastest speed while falling) of squirrels is slow enough that they will, at least in principle, never fall so hard that they hurt themselves.
Every year upwards of 25 million birds are killed in Canada due to collisions with buildings, communication towers, wind turbines, and as a result of being tangled into marine gillnets. From window decals to flashing lights, humans have tried numerous preventative measures to stop these deaths. Their degree of success depends on the method, the location, and the types of birds in that ecosystem—amongst many other factors—and results are highly variable.
What may seem like benign interventions that—at worst—just won’t work, actually have the capacity to do harm. As an example, In Peru, bycatch (i.e., accidental catch) of Guanay Cormorants was reduced more than 80% after researchers attached green lights to gillnets. At the same time, bycatch of Peruvian Boobies increased. Possibly due to the boobie’s attraction to the lights.
Similarly, when researchers set out to the Baltic sea to compare the effects of attaching light panels, constant green lights, or flashing white lights to gillnets on sea birds (in particular the Long-tailed duck, a vulnerable species) they found that the nets with flashing white lights caught more ducks than the normal, non-illuminated ones.
When non-native animals are introduced to an ecosystem, quite often, the very delicate balance of that environment is thrown off. Plants, animals, fungi, bacteria, and everything else in a biome are connected through the food web, meaning that small changes to any part of a habitat can have extensive consequences.
From zebra mussels in Canada to grey squirrels in the United Kingdom, invasive animals have become a massive problem with increases in global travel and shipping. We enact biosecurity laws and protocols, quarantine procedures and mandate pesticide treatments to try to limit their spread; but despite all our efforts to curb invasive invasions, there is one species that we tend to give a pass to: cats.
Domestic cats are not native to anywhere. While they are descended from Felis lybica, the African Wildcat, the domestic cat is a different species. They are even given a separate Latin species name: Felis catus.
Even when well fed at home, domestic cats often engage in predation and hunting behaviours. With some variance depending on location, cats tend to kill more birds and small mammals than anything else. Since domestic cats are an introduced species, they have tremendous potential to upset intricate ecological situations.
Some researchers strongly believe that domestic cats’ damaging influence on the environment has already been robustly demonstrated. They feel it is crucial to act immediately and decisively if we want to have any hope of counteracting the damage done by domestic felines. For example, in 2018, conservationists from Oklahoma State University and the Smithsonian Conservation Biology Institute published a paper wherein they denounced what they described as organised misinformation campaigns spreading junk science about domestic cats’ effects on ecosystems.
They invoke the Merchants of Doubt moniker—the name given to the “cabal of industry-beholden” contrarian scientists who denied evidence of harm by tobacco smoking, DDT and climate change for financial gain—and liken outdoor cat advocates to “cigarette and climate-change fact fighters” pushing “propaganda.”
Conversely, other researchers feel that many conservation scientists are fueling an unwarranted moral panic over outdoor cats with exaggerated claims and inadequate evidence. In response to the 2018 Merchants of Doubt publication, researchers from six universities around the world collaborated on a rebuttal. They wrote that:
equating the resources and power of global corporations and economic elites (e.g., Exxon Mobil) with the reach and advocacy of comparatively small non-profit organizations and university academics strains the [Merchants of Doubt simile] past the breaking point.
The authors take issue with conservationists concluding that cat advocates are acting with nefarious or bad faith motives and feel that calls for things such as “remov[ing cats] — once and for all — from the landscape” by “any means necessary” are sensationalist and premature. Instead, they call for better research to investigate the severity of the risks cats pose to habitats and the appropriate levels of interventions, and humane but effective alternatives to simply killing and banning outdoor cats.
A White-Hot Issue
If you’re not that familiar with the literary style research papers are usually written in, let me just say, it’s not usually quite like this. Usually, one side of an academic debate is not accusing the other of being corporate shills. The vast majority of the time, there are no mentions of “zombie apocalypse[s]” or calls to let things “weigh heavy on our shoulders.”
The rhetoric throughout the literature on outdoor cats is very inflammatory. The cats/birds issue isn’t just a problem to be solved. It is a fight; a conflict; a war. Solutions to this situation are needed urgently. Danger is imminent. “Drastic times call for drastic measures.” People “must ask themselves which animals should be saved but do so quickly because there is no time to [do both]… before extinctions occur”.
Clearly, the environmental impact of cats on birds, and the welfare of cats, are contentious and emotionally charged topics. It makes a lot of sense that they are. Environmental stewardship is an important role that humans are morally obligated to fulfill. Especially in the face of an existential threat. At the same time, cats also represent life that should be protected. Cats long ago transcended their status of just-another-animal. From their initial roles of pest control, they have become members of the family. Given as much, cat owners often take advice regarding their pets personally.
The thing is, this highly polarised landscape filled with provocative language and antagonistic interactions isn’t helping either side. And it isn’t helping the birds, or the cats, either.
Whether cats impact wildlife in a meaningful and long-lasting way is a question for the experts in this field. They do not seem to agree, which implies the need for more research on the matter. Either way, it doesn’t particularly matter who is “right” anymore.
What matters is how needlessly divided the debate has become.
A Birdy Binary
A false dichotomy has been created wherein one can either care about native wildlife or feline welfare, but never both. Either cats are the enemies — the representations of humans’ entitlement and disdain for the earth — or the most perfect companions, too often neglected and maligned, who are just following their natural instincts.
We do ourselves a massive disservice by reducing this complex and multifaceted issue to one side versus another, or ‘us versus them’. People are lumped into supposedly either loving birds and hating cats or vice-versa, when in truth, most conservationists and pet owners are motivated by similar loves of nature, flora, and fauna.
This artificial divide encourages more polarising solutions, more extreme takes and leads to fearmongering and moral panics. It not only creates this illusion of a lack of a middle ground, it eliminates any of the methods or solutions that would originate from there.
We can become so hyper-focused on advocating for one position that we become blinded to other parts of the issue. Habitat loss is displacing bird populations and climate change is affecting their ability to find food and water. As cities sprawl outward, they remove homelands for birds and disrupt migration routes. In Canada, around 100 million birds are estimated to die every year due to collisions with buildings, power lines and cars.
Such black-and-white thinking discourages the peer review process. With little room for nuance, any criticism of a study’s methods can be seen as dissent. Scientists need to feel free to question how research is performed and how it draws its conclusions without fear of being labelled as agents of misinformation.
It’s Getting Mean in Here
Outside of academic discussions, the binary division between perceived “bird lovers/cat haters” and “cat lovers/bird haters” is even wider. This pattern is seen to varying levels across social media, traditional media, and interpersonal relationships. Expressing the wrong opinion on Twitter about indoor/outdoor cats can lead to harassment and ostracisation.
We should all know that an anecdote is not good evidence for anything on its own. Nonetheless, let me tell you a short one.
I have written on a variety of “controversial” topics in the past — menstruation, copycat suicides, female ejaculation, transgender children, border walls — but only once have I been kicked out of a science-themed social media group. I was removed after sharing my (then) most recent article on whether bells on cat collars work to reduce the amount of prey that domestic cats kill. For the record, three studies (one published in 2005, one in 2006, and one in 2010) have shown that cats brought home less prey when they wore bells. But very quickly, the thread of responses devolved into name calling and insinuations of nefarious or financially motivated intentions.
Empathy works, not… whatever that is
What should be a logical debate on policies and practices has turned ugly. The cats and birds issue has become a hotbed for sensationalism and hyperbole, no matter your stance. And the worst part about it is that we know it won’t work as well as collaborative and kind approaches would.
We know that when trying to change somebody’s mind, what tends to work is empathy and ongoing dialogue. We want to avoid judgment, disdain, or anger. Scientists need to be transparent about how they draw their conclusions and accept legitimate criticisms. Science is not perfect or magic but just a tool to help us understand the world around us. Trust is crucial for effective communication of knowledge, and trust cannot be built on anything but honesty and openness.
Actually helping wildlife and domestic pets alike requires engaging with all stakeholders. Especially the ones that oppose your stance. As much as we may want to rant and kick and scream at the people who disagree with us, it’s pointless. Not only that, it’s actively detrimental to their understanding and your ability to communicate with them. Like with so many things, in science communication, kindness is key.
The Emerald Ash Borer (EAB) is a species of jewel beetle native to eastern Asia. In 2002, the beetle was detected for the first time in North America. First in Michigan, then Ontario, although tree ring analysis suggests that it has likely been present in those regions since the early 1990s. Since then, the number of EABs have increased year after year as the bugs spread across Ontario, Quebec and more than half the continental U.S.
An infection of EABs can kill an otherwise healthy ash in 2-5 years. But how can an 8.5 mm long insect kill a tree anyways? One way would be by eating all of its leaves. Without foliage, a tree has no way to photosynthesize, and therefore no way to make energy. Adult EABs do munch on leaves—a loss of tree canopy is a warning sign of EAB infestation—but not usually to the degree that would kill an ash. Instead, it’s the EAB larva that cause the majority of the damage.
EAB eggs are laid on ash branches, and larvae, once hatched, chomp their way under the bark. The little grubs will chew out 6 mm wide S-shaped tunnels called galleries to live in that can be up to 30 cm long. These galleries disrupt a tree’s internal water transport system, taking away its ability to send necessary nutrients up to its branches and leaves. As a result of nutrient deficiency, EAB-infected ash trees often show signs of chlorosis, or a lack of green colour in their uppermost leaves. Dying ash trees will sometimes send out epicormic shoots—little sprouts from the roots or lower trunk and branches—in an attempt to survive.
Most EABs spend winter inside ashes in their larval form. They’re able to withstand temperatures down to -30 ˚C, and are partially insulated by the tree bark. Eventually, come spring, the fully matured beetles will emerge from the ash trees, leaving small capital D-shaped exit holes about 4 mm wide.
The loss of one type of tree might not seem like such a cause for alarm, but the widespread death of ash trees is having many repercussions. In 2015, Montreal was home to roughly 200,000 ash trees. Mont Royal, the iconic park in the centre of the island was, until recently, home to over 10,000 of those trees. But, as a result of the EAB infestation the City of Montreal was forced to cut down about one-third of those ashes. The other two-thirds they chose to treat with preventative insecticides. To make up for the over 3000 lost trees, the city will plant 40,000 saplings. Of these, about 50% are expected to thrive. In 2016 Montreal committed $18 million to fighting the EAB and replacing the ashes it kills. In the U.S., affected states spend an average of $29.5 million per year to manage EAB populations.
The loss of ash trees can impede ecosystems, bring down home values or disrupt food webs. During bad weather, sick or dying ashes can pose a safety risk if they fall or drop branches. And with the loss of these trees comes an increased risk of landslides and flooding, both of which tree roots help to prevent.
A certain amount of the muddy colour can be attributed to the different colours of food we eat. Like mixing all the paint colours together, the result is a dull brown. But, much bigger factors for humans’ brown poop are bilirubin and bile. Bilirubin is a yellow substance found in the liver, the product of the breakdown of old red blood cells. Bile is dark brown or green and is produced by the liver to help digest fats. Both of these substances are secreted into the small intestine during digestion, and slowly make their way into poop, bringing with them a dark brown hue.
Bird poop, on the other hand, is not brown but white. That is because—unlike mammals—birds don’t pee!
How do fireflies create their telltale glow? It differs slightly depending on species—there are more than 2000 species of fireflies found across the world, including many that do not glow—but the one we know the most about is the North American Firefly (Photinus pyralis). It uses a molecule named luciferin and its enzyme buddy luciferase. Luciferase reacts with luciferin, causing it to break down into two compounds and release CO2 One of those two compounds has a bit of excess energy that it releases as light!
The production of this light has three requirements, other than luciferin and luciferase: magnesium, oxygen and ATP. That ATP requirement is a big part of why the luciferin assay has become an important tool for biochemical research. Adenosine-5′-triphosphate (ATP) is the universal “energy molecule” of all forms of life. So, luciferase and luciferin can be used to test if something like a cell is alive and still producing ATP.
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One group of fireflies, however, use their glowing abdomens to hunt. Females of the genus Photurisengage in aggressive mimicry by imitating the flashing patterns of other species’ females to lure and eat the males who seek mates.
Unfortunately, due to habitat loss and climate change, firefly numbers are declining across much of the world. The lack of appropriate green spaces for fireflies to live and mate is compounded by the sedentary nature of many firefly species. The larvae of the common European glow-worm are reported to move only about 5 meters (16.4 feet) per hour. Light pollution as well may be impacting fireflies’ ability to thrive. In one study, light pollution reduced the flashing of Photuris versicolor by almost 70%.
Ada McVean 