Category Archives: Animals & BIology

Crazy Cats and Brain Parasites


Brain parasitesIt reads like a script for a scary movie: an alien parasite invading our brains, taking control of our minds, changing our behaviour silently, secretly; making us do what it wants. And it’s happening now, in homes across Canada and the USA. Alien puppet masters over-running the nation, one household at a time.

But it’s not fiction, although my scenario is a trifle exaggerated.

They’re not some right-wing aliens from outer space subverting our natural goodness and compassion; not some cyber-bullying bloggers dripping political poison into the gullible minds of their readers.They are microscopic, found worldwide, on land and in water – including saltwater – and may be infecting people you know this very minute. Or even you. They’re Toxoplasma gondii; an amoebic parasite pretty much capable of infecting any warm-blooded creature.

Where they breed, however, is in your cat, and are then excreted in their feces:

Although T. gondii can infect, be transmitted by, and asexually reproduce within humans and virtually all other warm-blooded animals, the parasite can sexually reproduce only within the intestines of members of the cat family (felids). Felids are therefore defined as the definitive hosts of T. gondii, with all other hosts defined as intermediate hosts.

As an owner of four cats and having had cats most of my life, this is troubling. But not entirely new. Back in 2012, in an article in The Atlantic, titled, “How Your Cat Is Making You Crazy,” Kathleen MacAuliffe wrote:

The parasite, which is excreted by cats in their feces, is called Toxoplasma gondii (T. gondii or Toxo for short) and is the microbe that causes toxoplasmosis—the reason pregnant women are told to avoid cats’ litter boxes. Since the 1920s, doctors have recognized that a woman who becomes infected during pregnancy can transmit the disease to the fetus, in some cases resulting in severe brain damage or death. T. gondii is also a major threat to people with weakened immunity: in the early days of the AIDS epidemic, before good antiretroviral drugs were developed, it was to blame for the dementia that afflicted many patients at the disease’s end stage. Healthy children and adults, however, usually experience nothing worse than brief flu-like symptoms before quickly fighting off the protozoan, which thereafter lies dormant inside brain cells—or at least that’s the standard medical wisdom.

But if Flegr is right, the “latent” parasite may be quietly tweaking the connections between our neurons, changing our response to frightening situations, our trust in others, how outgoing we are, and even our preference for certain scents. And that’s not all. He also believes that the organism contributes to car crashes, suicides, and mental disorders such as schizophrenia. When you add up all the different ways it can harm us, says Flegr, “Toxoplasma might even kill as many people as malaria, or at least a million people a year.”

To be fair to cats, the parasites live in soil, too, so they’re hard to avoid. Plus they’re also found in undercooked meat. You like your steak blue? Or bloody rare? You may be inviting this parasite into your brain. And also if you drink contaminated water or eat uncooked or undercooked shellfish. Those raw oysters you love? Parasite havens. Yum.
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The Utility Animal


In the July/August edition of Pets Magazine (the Cat Care issue) there are two articles that caused me concern. One is “The Loyalty and Bravery of a Cat” (p.28), the other is “Quick-Thinking Cat Saves the Day.” (p.26). The latter is a pet profile from the Purina Hall of Fame that honours pets for “extraordinary actions.” The former is about a YouTube video showing a family cat attacking a dog that had itself attacked the family’s four-year-old son.

The acts themselves and the cats involved are extraordinary and deserving of praise as individual animals. But the idea that cats in general need to be propped up as utility animals, that in order to have intrinsic value they need to perform some service for humans, bothers me deeply.

It also annoys me that cat lovers feel the need to be defensive about cats and find ways to make them seem more like dogs. They are separate species with very different social (pack) cultures and cannot be expected to behave like one another.

All animals evolved to fulfill their own purpose. Some have become domesticated through their interactions with humans; a few are even companion animals we call pets. Dogs and cats top that small list. And a small percentage of those perform acts that are of use or beneficial to humans.

Valuing an animal on the basis of its utility is to devalue the life of that animal. Animals do not exist to serve human needs. Yes, they can be trained to perform tasks, but that isn’t their purpose.

Cats have value simply by being cats. All life has its own inherent value and we cannot measure that value against its usefulness to our lives. Not should not – cannot. There is no appropriate measuring stick.

Any attempt only promotes subjective value judgments over other species. It’s akin to measuring the distance to a neighbouring planet by the number of bicycle lengths between us. Irrelevant.

Value your pet, value all life, for what it is. Not what use, not what advantage and not what profit you can gain from it. And I am happy to share my home with my pets for the sake of their companionship alone.

Gut instincts


Ars TechnicaA story on Science Daily says research suggests our so-called “free will” may be less free than we ever imagined. We may, instead, be meat puppets ruled by the desires and cravings of the smallest symbiotes we carry: our gut bacteria.

The story opens:

It sounds like science fiction, but it seems that bacteria within us — which outnumber our own cells about 100-fold — may very well be affecting both our cravings and moods to get us to eat what they want, and often are driving us toward obesity… researchers from UC San Francisco, Arizona State University and University of New Mexico concluded from a review of the recent scientific literature that microbes influence human eating behavior and dietary choices to favor consumption of the particular nutrients they grow best on, rather than simply passively living off whatever nutrients we choose to send their way… the authors believe this diverse community of microbes, collectively known as the gut microbiome, may influence our decisions by releasing signaling molecules into our gut. Because the gut is linked to the immune system, the endocrine system and the nervous system, those signals could influence our physiologic and behavioral responses.

Actually this is not really surprising. It has long been known that human evolution has been affected by both viral and bacterial presence, as well as having our own DNA encoded with bits from them. And recently it was discovered bacteria can encode DNA from other animals – even dead ones – into their own.

The discovery of the recombinant DNA process should have alerted everyone to the wider possibility that there may be biological analogues already. After all, it only makes sense that in any symbiotic relationship, there must be some way for all parties to communicate with each other for mutual survival. The gut is a competitive environment with numerous species, so they also need a mechanism for cooperation and communication in ways that also help keep the host alive.

Most life on the planet has some form of symbiotic relationship and many are mutually beneficial like that with our gut flora, although there are also parasitic relationships as well.

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Gangs of Feathered T-Rex


Packs of tyrannosaurs
Imagine, if you will, an early morning scene in the late Cretaceous. The air is quiet as the day warms. At the edge of a large forest a plain of ferns ripples in the light breeze (grass would not evolve for another 20 or so million years). Under the canopy of the ancient beeches and maples, there is movement. Nothing fast, just a hint. A flash of mottled colour against the background. A glint of light off an eye. A soft snuffling. A feather falls silently to the forest floor.

Among the nearby ferns, a pack of ceratopsians grazes, adults watching the woods carefully, nervously, herding the young towards the safety of the pack’s centre with prods of their heads, honking to get the young ones’ attention. They eat the flowers that dot the plain among the ferns and cycads, chew the horsetails that grow at the edge of the ponds and streams. A youngster sees a tasty patch of moss and, unnoticed, slips out between the elders to get it.

Suddenly the forest explodes. Leaves scatter and branches snap as the muscular forms crash through the cover and converge on the young triceratops, separated from the horned protection of the pack. Two large adults, a teenager and two younger tyrannosaurs running a well-coordinated hunt as they have done many times int he past. Their speed makes them a blur against the trees.

The ceratopsians bellow in fear and rage, and quickly form a circle, heads out, protecting the oldest and youngest within the centre. The pack of tyrannosaurs’ charge sounds like thunder, and they screech in anticipation as they race to surround the doomed youngster. They circle rapidly, darting to avoid the feeble attempts at defence from the surrounded dinosaur.

The herd can’t save it, and they move away, quickly, the outer ring still shuffling backwards to keep their ferocious, horned heads facing the danger. The tyrannosaur pack ignores the herd as it feeds, tearing off chunks of the living flesh as the youngster’s screams get fainter.

Their hunger slaked for the moment, the pack would soon retire to the forest to look for another easy target that might venture close by.

Triceratops vs tyrannosaur

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