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.
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.
If you have avoided having poinsettias in your home because of small children or animals, you’re not alone. But despite the commonly held belief that poinsettias are toxic, they aren’t. This myth seems to have originated in 1919 with a misattributed poisoning of a child and perhaps persisted because several members of the same family as the flower are quite toxic.
These leaves, however, aren’t meant for your salad, so eating even a couple can give you an upset stomach or cause vomiting. This is the reaction commonly seen in dogs and cats, but since these symptoms are mild, oftentimes no veterinarian care is required, although you should contact your vet if your pet is sick for more than a few hours.
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.
It’s probably not news to anyone reading this that lead exposure is dangerous, but when most of us think of routes to lead exposure we think of leaded gasoline, paints, drinking water or pencils (although pencils do not, and never did, actually contain lead). But there is another means of exposure that’s causing significant issues for certain populations: lead bullets.
Bullets have traditionally been made from lead for several reasons. The metal is cheap and melts at only 327˚C (621˚F) meaning that it can easily be formed into bullets. It is also very dense, so that lead bullets pack a big punch, so to speak. But lead is also toxic.
After an animal is hunted, even if care is taken to remove the bullet from the carcass, lead contamination of the meat can still occur. Part of the problem comes from the fact that lead bullets often fragment into many small pieces that can disperse throughout the tissue. These lead fragments can then be consumed by the humans or pets who eat this meat.
Severalstudies have shown that when game is hunted, killed, processed and cooked in standard ways, higher-than-normal levels of lead are found in the meals. This lead contamination especially influences those who rely on game meat as their primary source of food, such as those in Greenland, or Indigenous Canadians, or those using food banks for whom donations from hunters are fairly common.
Even occasional game meat eaters, however, can be affected by lead contamination. Health Canada states that blood lead levels below 5 μg/dL are associated with adverse health effects. One study found that those eating one or fewer meals of gamebird shot with lead bullets per week showed blood lead levels of 7.5 μg/dL, and those eating gamebird meat daily showed blood lead levels of 17 μg/dL. But the effects of lead bullets don’t stop with humans.
As it’s fairly common for hunters to eviscerate their quarry in the field and leave behind the unwanted viscera, scavenging animals can feed upon the discarded remains of humans’ prey and ingest lead in the process. This can lead to many of the same symptoms as human lead exposure.
Another route for exposure is found in birds’ gizzards. To help break down their food birds swallow small rocks and store them in their gizzards. The problem is that to a bird a bullet looks a lot like a small rock.
One Italian study found that those who engaged in hunting showed a blood lead level almost double those who didn’t. This could be from the lead fumes that are released when guns are fired or from handling lead ammunition. The same study did not find any relationship between blood lead levels and consuming game meat, which could point to some regional differences in ammunition manufacturing, hunting or cooking styles influencing the amount of lead that makes it into a final dish of cooked game meat.
Lead exposure can also occur in humans that are shot with lead-based bullets, especially since bullets are sometimes left in a victim’s body, either due to lack of medical attention or complications that would arise from trying to remove them. In some cases, symptoms can occur many years after the gunshot wound. To remedy this, a combination of drugs to help eliminate lead from the body, chelation therapy and surgery to remove the bullet are used.
The good news is that non-lead bullets are becoming more popular. Several places have enacted lead munition bans, and one study showed that non-lead bullets were just as effective for hunting animals as lead bullets. Those who handle bullets in their jobs (such as police or military personnel) would benefit from a switch to non-lead-based munitions, but beyond environmental and health benefits, switching away from lead bullets would also have an economic benefit, as this study shows. As for what could be used instead of lead, there are a few options, the most popular of which seems to be copper, but the most interesting of which is definitely depleted uranium.
Cat scratch disease (CSD) is an infection resulting from a scratch or bite of a cat (or, in rarer cases, dogs or other animals). It is not the same thing as Cat Scratch Fever, an album by Ted Nugent, although CSD can cause a fever, as well as swollen lymph nodes, lethargy, neuroretinitis and headaches.
CSD is the result of an infection by Bartonella henselae, a bacterium commonly transmitted to cats via the cat flea (yes, cats and dogs usually have different fleas). Rarely, ticks and spiders can also carry the bacterium, and transmit it directly to humans.
Kittens are more likely to carry Bartonella henselae than adult cats due to their underdeveloped immune systems, and are much more likely to bite or scratch their owners while learning how to play gently. But anyone who is exposed to cats of any age should take care to clean any wounds well to avoid risk. Bartonella henselae can also be transmitted to humans via cats’ saliva, so as sweet as it may seem that Fluffy is licking your wounds for you, probably best to wash it and wear a Band-Aid.
For veterinarians, CSD is actually considered an occupational hazard. Vets are frequently in close proximity to many cats, oftentimes cats that are acting aggressively and are more likely to bite or scratch. One study found Bartonella DNA in 32 of the 114 veterinarian patients they tested.
CSD is diagnosed via blood test, or simply by considering the symptoms of the patient, the most obvious of which is a swollen blister or sore and red area surrounding the infected bite or cut. Those who are immunocompromised (such as patients with HIV), very young or very old are more likely to be infected, and rates of infection generally increase during spring in North America, likely due to the birth of many new kittens.
So while they may be as cute as anything, cats do still pose a risk to their owners, and not only because they may destroy your favourite furniture.
The kitty in the picture is named Jean-Charles and he is available for adoption from the Réseau Secours Animal in Monteal now!
Leafcutter ants can strip as much as 17% of the leaf biomass from plants in their ecosystem and can clear entire trees in under a day. Next to ours, leafcutter ant society is the most complex society on earth. They build nests that can contain thousands of rooms and cover up to 0.5 km2, a feat that is necessary since a mature colony can contain more than eight million individuals.
But if they’re not eating the leaves that they carry home, what are they doing with them?
Farming. Leafcutter ants use leaves as their fertilizer to grow their crop: fungus.
They cultivate their fungal gardens by providing them with freshly cut leaves, protecting them from pests and molds, and clearing them of decayed material and garbage. In return, the fungus acts as a food source for the ants’ larvae. The ants are so sensitive to the fungi’s needs that they can detect how they are responding to a certain food source and change accordingly. This symbiotic relationship also benefits from a bacterium that grows on the ants’ bodies and secretes antimicrobials, which the ants use to protect their fungi.
Adult ants don’t feed on the fungus, but rather get their nutrients from leaf sap. Smaller adults often hitchhike on leaves being carried back to the nest to opportunistically feed on the sap, as well as protect the carrier from flies and to check that the leaf isn’t contaminated with other fungi.
Leafcutter ant society is divided into castes, with each group having a different role to play. The largest ants, called Majors, act as soldiers and heavy lifters. They guard the nest and help to clear out the highways between the nest and a food source. The next smallest caste, the Mediae, is made up of generalists, cutting and transporting the bulk of the leaves for their colony. Next in size are the Minors, who protect the foraging path and food source, and the smallest ants, the Minims, work exclusively at home, tending to the larvae and fungus garden.
Some Minims work exclusively as garbage collectors, removing decaying organic matter from their fungal gardens and transporting it to dedicated garbage rooms placed well below the rest of the nest. After becoming garbage collectors, these ants will never interact with the fungus or the queen, to prevent any disease from being passed onto them.
Leafcutter ants are often presented as a single species of ant, but in reality, there are 250 species of ants which practice fungus farming. Besides their agrarian tendencies, these ants have something else in common: queens. When it comes time to establish a new colony, winged virgin queens-to-be take part in their nuptial flight and mate with many different males to collect sperm. They then set out to find an appropriate place for a new colony, bringing with them a piece of the fungus to seed their new fungal gardens.
Goats are really useful creatures. We use their milk, fur, meat and… firefighting skills?
In several places goats and sheep are being herded into fire-prone areas. The hungry herbivores move through the land, munching on shrubs, trees and grass, and creating firebreaks. Since goats only stand about 1 metre tall, they will graze heavily on low-lying plants, creating a gap between the ground and higher trees. This gap can prevent fires from spreading or slow them down. Some places in Spain have even blamed recent wildfire severity on the declining number of herds grazing on the land.
Goats are perfect for the job for a few reasons. Unlike some grazers, goats do not limit themselves to leaves or grass, eating the wood and bark of smaller plants as well. Goats are able to traverse a wide variety of terrains, and they are naturally resistant to several toxic plants. They can also be herded in tandem with sheep or cows, creating an even more effective grazing party. Using goats comes with the added advantage of reducing the carbon footprint, compared to clearing brush with machines, and improving air quality. The waste left by goats is simply absorbed into the ecosystem of the area.
Studies have shown that a herd of 250 sheep can reduce the available plant mass by 75% in 30 days. When a wildfire in Utah with 15-foot-high flames reached an area that had been cleared by goats, the flames dropped to only 3 feet tall in lightly-grazed areas and stopped entirely in more heavily-grazed ones.
The biggest barrier to using goats in this way is a lack of trained and skilled herders and herding dogs to manage the goats. So, if you’re looking for a career change, a position in goat herding is probably available. Given goats’ relative quietness and lack of air-polluting outputs, they could be especially useful for grooming areas near residences and towns, so you may not even have to commute very far.