When we think of dogs-with-jobs our minds tend to go straight to police, search and rescue, drug-sniffing and guide dogs. But therapy dogs are the unsung heroes of the working dog world! These four-legged therapists undergo detailed training to help comfort, support and encourage people suffering from a variety of mental health issues. They work in all kinds of conditions — from hospitals to group homes — to bring their special brand of assistance to those who need it most. Let’s take a closer look at how these four-legged heroes are helping humans.
I wouldn’t blame you for thinking something along the lines of “just like everyone else,” but I’m here to tell you otherwise.
Being a veterinarian is a lot like being a human doctor. Besides the fact that both professions practice medicine, albeit on different subjects, they both require top grades and many years of school. They usually necessitate one to go into debt, to work long hours, to have extreme empathy and to be on call for days at a time.
Given their similarities, we’d expect them to have similar mortality rates and causes of death, but that isn’t the case. Veterinarians are at an extremely elevated risk for suicide.
Humans might not have hair as thick as chimpanzees covering their body, but our arm, leg and eyebrow hair all serves as reminders of our primate ancestry. So why don’t Homo sapiens have whiskers like other simians? To answer that, let me explain first what whiskers do, besides look adorable.
Whiskers are vibrissae, keratin filaments that grow out of different follicles than hair. Whisker follicles are much deeper than hair follicles and are surrounded by pockets of blood that amplify vibrations to better communicate information to the nerve cells beside the follicles. You may have noticed when looking at your cat that there are 2 kinds of whiskers, long and short. Long whiskers are macrovibrissae and can be moved voluntarily. Animals use these to sweep areas (called whisking) to navigate spaces and generally feel the world. Short whiskers are microvibrissae, and they cannot be moved voluntarily. These are used specifically for object recognition, whether it’s your rat’s favourite toy or your hand.
In general, animals use whiskers to help them ‘see’ the world, navigate it and identify features. Humans used to have whiskers too (about 800 000 years ago we lost the DNA for whiskers), but have now largely integrated the function performed by whiskers into their brains, specifically into their somatosensory cortex. The human brain devotes relatively huge portions of itself to sensing and processing touch.
Certain areas of the body, like fingertips, lips and genitals have much greater sensitivity to touch than other areas like the back or legs. A visual representation of this sensitivity to touch can be seen in the Cortical homunculus, or by performing a simple test: Have a friend use 2 pencils to touch your arm, while you close your eyes. Have them move the pencils closer and closer together. At a certain point, you will not be able to distinguish whether you are being touched by 1 or 2 pencils. Have the friend repeat this activity on your fingers, then your back. You’ll quickly notice that you have a much more sensitive sense of touch on your hands, feet and face. This test is called the 2 point discrimination test, and it’s often used to test patients for paralysis.
So we as humans may not have cute whiskers anymore (though our simian cousins still have microvibrissae), but rest assured we’re no worse off for this loss, just slightly more dependent on our brains.
Evolution is often thought of as a solely long-term process. But the conception that its effects are only seen after millions of years ignores a crucial part of the evolutionary process: adaptation. Because we tend to fixate on the drastic changes caused by evolution over huge timescales, it’s easy to ignore the small variations between generations that add together over time to form the big evolutionary changes we focus on. This unintentional side-lining of small adaptations can blind us to the ways in which humans are directly affecting the evolutionary processes of nature. From tuskless elephants to fish that can’t smell, animals are developing specialized adaptations to allow them to live in ecosystems that have been disrupted and altered by mankind. These adaptations are one step in the evolutionary process that already bears the unmistakable marks of humanity’s influence.
Just as humans are changing the planet, they’re changing the fauna that inhabit it. Here are some examples of how.
While it seems that cats, and in rare circumstances, dogs, can become infected with SARS-CoV-2, there is no need to panic. Pets tend to exhibit very mild symptoms and make full recoveries. There’s no evidence at this time that COVID-19 can be spread from animals to humans, and although the same cannot be said for humans to animals, the transmission rates seem very low.
Despite what movies would have you think, rats barely ever make any sounds, at least those that humans are able to hear. Rat’s vocalizations start at around 2 kHz and extend as far up as 100 kHz. For reference, human’s can hear roughly 2-20 kHz, so the vast majority of rat noises made are well into the ultrasonic spectrum. Pet and wild rats alike will seem almost mute, unless put into extreme distress, when they will squeak or shriek audibly. If you record rats with an ultrasonic microphone however, you find that they actually make many noises, to convey everything from joy to dominance and even to laugh!
Consider these pros and cons before attaching a bell to your cat’s collar.
Does your cat bring you dead animals? While this common behaviour is kind of yucky, it’s also sort of endearing – your cat is bringing you what she believes to be an excellent gift. But despite their generous intentions, hunting by domestic cats is affecting ecosystems and pushing some species to extinction. So what can you do to keep your cat from catching wildlife? There are two primary solutions to consider: keep her inside, or attach a deterrent (such as a bell) to her collar.
A closer look at the options
Of course, the easiest method of preventing your cat from killing birds and rodents is to keep her inside all the time. In the safety of your home, your feline’s exposure to prey animals will be limited to any mice that happen to get into your house. If you aren’t willing to curb your feline’s wanderlust, a common alternative is to attach a bell to her collar to alert wildlife of her approach. But is this a safe and effective option?
The pros and cons of bells
A number of studies have looked at whether or not bells help prey escape from cats, and the general consensus is yes! Bells on collars seem to reduce the amount of prey caught by about half, which could be enough to no longer pose a threat to ecosystems.
Effectiveness aside, many pet parents worry that a bell will hurt their cat’s ears. According to Veterinary PhD student Rachel Malakani, a collar bell will produce sound at about 50-60 dB, but studies have shown cats to be unaffected by sounds under 80 dB. While some cats with anxiety may not react well to the bell’s sound, it’s likely that the majority of cats simply won’t care.
Some owners worry that as well as alerting prey, a bell would also alert large predators to a cat’s presence. While this is possible, given most predator’s acute hearing, it’s unlikely that the relatively quiet noise of a bell would make the difference between your cat getting detected or not. If you live in an area where your cat is at risk of being attacked by large animals you should probably be keeping your cat indoors anyway, or at least supervise their outdoor activities. You can also invest in a cat enclosure, which will allow your feline to enjoy the fresh air safely!
If you’re unwilling to put a bell on your furry buddy, you do have another option – cat bibs. Sold under names like Birdsbesafe, these devices are brightly colored to alert potential prey to the cat’s presence before they can pounce. While your cat might look a bit silly wearing a rainbow bib, the scientific research on these products shows they reduce predation rates by roughly the same amount as bells. That said, the devices that rely on color to alert potential prey work much better on birds (who have very good color vision) than they do on small mammals (who generally have quite poor vision).
If you’re scared of attaching any collars or collar-mounted devices to your felines – you shouldn’t be. While fears that cats can become strangled or trapped by a collar caught on debris are common, actual adverse effects from collars are rare. One study looked at 107 veterinarian practices and found only one collar-related injury per every 2.3 years, with collar-related deaths being even rarer. You can mitigate your fears further by using a breakaway collar.
If your cat ventures outdoors, especially if you live in an area with endangered species, please do your part to aid conservation efforts by outfitting your kitty with an anti-hunting device.
If you ask a dog owner what dogs cannot eat, they’ll list some foods like onions, garlic, rhubarb, grapes and chocolate. (As an aside, if they say grains, don’t listen to them.) Dogs’ inability to safely consume chocolate is common knowledge, but thanks to their proclivity for eating anything they can get their mouths on, many dogs are nonetheless treated for ingesting chocolate every year.
However, there are also many, many dogs who eat chocolate (with or without their owner’s knowledge) who are perfectly fine, no treatment necessary. If chocolate is so bad for dogs, why are these candy-consuming canines fine?
Because, as with all things, the dose makes the poison.
The components of chocolate that are toxic to dogs are theobromine and caffeine. These two chemicals are, structurally, almost identical, and both belong to a group of chemicals called methylxanthines.
Part of what makes methylxanthines so dangerous to animals is how slowly they process them, in particular, theobromine. While dogs reach peak serum (the non-cell part of blood) levels of caffeine after 30-60 minutes and eliminate half of an ingested dose in 4.5 hours, they don’t reach peak serum levels of theobromine until after 10 hours and take 17.5 hours to eliminate half of it.
While they’re in the blood, methylxanthines have a few effects. Primarily, they inhibit the activation of adenosine receptors. These receptors are generally responsible for making us feel sleepy, and decreasing the activity of our bodies. Methylxanthines inhibit these sleepy feelings and act as stimulants.
An aside: Grapefruit’s effects on theobromine metabolism
The enzyme responsible for metabolizing theobromine is a member of the cytochrome P450 family. If you’ve heard of these enzymes its likely because you take a medication that is similarly affected by them (such as Viagra, Cialis, Erythromycin, Xanax and many others) and you’ve been warned to stay away from grapefruit juice. This is due to compounds in grapefruit interfering with the P450 enzymes. Without properly functioning enzymes, medications aren’t broken down as they should be, and overdoses can occur. These compounds aren’t exclusive to grapefruits: they’re also found in pomelos, bitter oranges and Seville oranges that are used to make marmalade. Luckily dogs don’t often consume the fruits that harbour these compounds, however, if Marmaduke ever eats a jar of marmalade as well as some chocolate, he would be in serious trouble.
So, what does this mean for your dog who ate a chocolate bar? It means they will feel nauseous and probably vomit, they’ll have a high heart rate, diarrhea, show signs of hyperactivity and, if they consumed a high dose of methylxanthines, tremors, seizures and possibly death.
What exactly is a high dose of methylxanthines however depends on your dog.
According to the ASPCA mild effects of theobromine poisoning can be seen at a dose of 20 mg/kg. Severe signs begin at about 40 mg/kg and seizures can begin at 60 mg/kg. A median lethal dose (LD50) is the dose of a toxin required to kill half of a sample population. It’s a common way of measuring a lethal dose of a substance in toxicological research, and for theobromine, the LD50is 100-200 mg/kg.
Notice that because all of these doses are given per kilogram of dog, what’s a low dose of theobromine for a German Shepard could be an exceptionally large dose for a chihuahua.
To illustrate my point, allow me to introduce three dogs. First, we have Baci, a 5-year-old, 7-kg Maltipoo. She’s considered a small dog by all reasonable metrics.
Next meet Chanelle, a 10-year-old Golden Retriever who is solidly medium-sized at 25 kg.
Last, we have Jupiter, a 5-year-old Malamute/German Shepherd cross who is quite large at 50 kg.
I’ve run some numbers to see how each of these dogs would fair if they ate the same amounts of chocolate. You can see my results in the chart below and can replicate my calculations easily using one of the online chocolate toxicity calculators.
(Green = <20 mg/kg, yellow = 20-40 mg/kg, red = 40-60 mg/kg, black = >60 mg/kg)
So, we can see that while Jupiter will probably be fine if he scarfs down 1/3 cup of cocoa powder (the amount in your average recipe for brownies), Chanelle would likely be sick, and Baci would be facing seizures and possibly death.
It’s easy to see, when you start playing with the numbers, how so many dogs can eat chocolate-containing foods and be totally fine. Chanelle could easily consume ½ cup of chocolate ice cream, or a chocolate pudding cup, or a chocolate cupcake and not even show the slightest sign of being sick!
An aside: What about mulch made from cocoa bean shells?
In recent years cocoa-bean-based mulch has gained popularity as an attractive alternative to traditional mulch. It can be good for your garden, contributing nutrients and preventing weed growth, but it can be really bad for your dog. With up to 32 mg of theobromine per gram, cocoa bean mulch can be a more potent source of theobromine than even pure unsweetened baking chocolate. If you can’t guarantee that a dog won’t munch on your mulch, you’re better off sticking to the traditional mulches, which come with the bonus of being much cheaper!
Even if your dog doesn’t get sick from eating small amounts of chocolate however, it’s still best that they avoid it. One study found that repeated theobromine exposure led to the development of cardiomyopathy (a chronic disease of the heart muscle that makes it harder for the heart to pump blood) in dogs.
An aside: There may also be a genetic component to dogs’ ability to metabolize theobromine
Dogs with a particular variant in their CYP1A2 gene (the variant is 1117C>T) lack the ability to properly metabolize and break down some substances, including lidocaine, naproxen and theobromine. This has important implications in their veterinary treatment and could explain why some dogs get sick after eating very little chocolate.
So, what should you do if you suspect your dog has eaten chocolate? You have a few options. You can check an online calculator (like this one) to see if your dog is likely to exhibit symptoms, or call animal poison control (1-888-426-4435 in Canada and the U.S.). Keeping in mind that such resources are not substitutes for veterinarian care, you should monitor your dog closely no matter what they say, looking for symptoms like a fast heart rate, vomiting or tremors.
If your dog ate an unknown amount of chocolate; is exhibiting symptoms; is pregnant (theobromine can cross the placenta and affect the puppy); or has other health complications, you should take them to a vet right away. Symptoms may not develop until up to two hours after ingestion, but veterinarian anti-chocolate treatments are most effective if performed as soon as possible after ingestion.
And what exactly do they do to cure a dog of theobromine poisoning? Gastric decontamination. The first step is to empty the stomach (if the ingestion was recent enough). This is often done with a drug called apomorphine which is administered through the eye so that it is quickly absorbed.
Next a vet will administer activated charcoal, a finely powdered material capable of binding a variety of drugs and chemicals. Activated charcoal is most effective if given immediately after ingestion of the toxin and is usually given by mixing it with wet dog food (beware: it will turn your dog’s poop black). In some cases, repeat administrations of charcoal are necessary, but in others just one dose will do it.
Beyond these steps, a theobromine-poisoned dog will just be given medicines to manage their specific symptoms, such as Diazepam for seizures or hyperexcitability, beta blockers for high heart rate, Atropine for low heart rate or others.
Before you go: a note on cats
As it turns out, cats are actually more susceptible to theobromine poisoning than dogs, but we don’t ever hear about a cat getting sick from eating chocolate. Why is that?
Mainly because cats don’t eat as indiscriminately as dogs. Dogs are known for eating just about anything they can find (including joint butts, a practice that places them at risk for cannabis poisoning), whereas cats tend to be picky eaters. In part this is explained by the fact that cats lack the ability to taste glucose.
If all chocolate tasted like 100% dark chocolate, you likely wouldn’t eat much of it either.
Take-home message: • Chocolate is poisonous to dogs mostly because of its theobromine content, which dogs are unable to metabolize effectively. •The amount of chocolate a dog can eat without showing symptoms varies drastically with their weight • If your dog eats chocolate, you should monitor them closely and seek veterinary attention if they show any symptoms, or if they are very young, pregnant or have other health concerns.
Special thanks to Rachel Malkani MSc. CDBC and veterinary PhD candidate, and to Henry for inspiring this article by, as you may guess, eating chocolate.
Our fingerprints are a one-of-a-kind pattern, so unique to an individual that even identical twins don’t share them. And yet I’m here to tell you that you inherit part of your fingerprint from your parents. Huh?
If you look closely at your fingerprints, you’ll notice that their patterns are one of three main types: loops, whorls or arches.
If you were to look at your fingerprint under a microscope though you’d see that while the ridges on your fingers follow one of the patterns, there are small variations in them, like breaks, forks and islands.
While the general shape of your fingerprints is heritable, these small details, often called minutiae, are not. Why that is comes down to how fingerprints are formed.
When a fetus is about 7 weeks old, they begin to form pads on their hands and feet called volar pads. These pads only exist for a few weeks, because at around 10 weeks they start to be reabsorbed into the palms of the hands and feet.
Around this time, the very bottom layer of the epidermis begins to form folds due to pressures from the growing skin. These folds are the precursors to your finger ridges, or fingerprints, and the pattern they take depends on how much of the volar pad has been absorbed when they begin to form. If the volar pad is still very present, then you’ll develop a whorl pattern. If the volar pad is partially absorbed, you’ll form a loop pattern, and if it’s almost entirely absorbed, you’ll form an arch pattern.
So how do genetics come into this? Well, the rate of volar pad reabsorption and the specific timing of the creases in the epidermis appearing are genetically linked. However, these events only determine the general shape of the fingerprint. The minutiae are influenced by things such as the density of the amniotic fluid, where the fetus is positioned and what the fetus touches while in utero. Since every fetus will grow in a different environment, their minutiae will differ. Even twins that share a uterus will interact with their surroundings differently. So even if your fingerprint shape matches that of your parents, if you look closer, you’ll see the differences that make your prints uniquely yours.
Did you know that fingerprints aren’t only a human feature? To read about fingerprints in koalas, click here!