Archive for the ‘Cats’ Category
Imagine a world without fear. It might be empowering to go about your daily life uninhibited by everyday distresses. You could cross highways with confidence, take on all kinds of daredevilry and watch horror flicks without flinching. Yet consider the prospect a little more deeply, and the possibilities become darker, even deadly. Our fears, after all, can protect us.
The basic aversion that a mouse has for a cat, for instance, keeps the rodent out of death’s jaws. But unfortunately for mice everywhere, there is a second enemy with which to contend, one that may prevent them from experiencing that fear in the first place. A unicellular organism (a protozoan), Toxoplasma gondii, can override a rodent’s most basic survival instincts. The result is a rodent that does not race away from a cat but is instead strangely attracted to it.
Toxoplasma‘s reach extends far beyond the world of cat and mouse. It may have a special relationship with rodent and feline hosts, but this parasite also infects the brains of billions of animals on land, at sea and in the air. Humans are no exception. Worldwide, scientists estimate that as many as three billion people may be carrying Toxoplasma. In the U.S., there is a one-in-five chance that Toxoplasma parasites are lodged in your neural circuits, and infection rates are as high as 95 percent in other countries.
For most people, this infection appears asymptomatic, but recent evidence shows that Toxoplasma actively remodels the molecular landscape of mammalian brain cells. Now some researchers have begun to speculate that this tiny single-celled organism may be tweaking human health and personalities in stealthy, subtle ways.
What the cat dragged in
Researchers first discovered T. gondii in 1908, and by the end of the 20th century they had a good grasp on how people could pick up this parasite. The story starts with cats: for reasons that scientists have yet to unravel, Toxoplasma can sexually reproduce only in the feline gut. The parasite breeds within its feline host and is released from the feline’s tail end. Cats are such obsessive groomers that it is rarely found in their fur. Instead people can become infected from kitty litter or by ingesting it in contaminated water or food.
Within a new host the parasite begins dividing asexually and spreading throughout the host’s body. During this initial stage of the infection, Toxoplasma can cause the disease toxoplasmosis in immunocompromised or otherwise susceptible hosts, leading to extensive tissue damage. Pregnant women are particularly at risk. If a woman is infected with Toxoplasma for the first time during pregnancy, the parasite may invade the developing fetus, cutting through tissues and organs as it spreads from cell to cell. Infection early in pregnancy can result in miscarriage or birth defects.
In otherwise healthy individuals, however, the only symptoms during this period are brief, flulike discomforts such as chills, fever and body ache. Within days the immune system gets the parasite under control, and Toxoplasma retreats into a dormant state. It conceals itself within a hardened wall in the host’s cells, a structure called a tissue cyst.
This stage of the infection has no other discernible symptoms, but individuals with dormant infections who develop compromised immune systems—because of AIDS, an organ transplant or chemotherapy—may experience severe complications. With the body’s defense systems weakened, Toxoplasma can reactivate and grow uncontrollably.
Once infected, a person will remain a carrier for life. Our immune system is apparently incapable of eliminating the tissue cysts, nor can any known drug. Nevertheless, the infection, detectable with a blood test, has long been viewed as relatively benign. After all, many people carry this parasite with no obvious ill effects. Only recently have scientists begun reexamining this belief.
Eat me, Mr. Kitty
In the 1980s researchers noticed unusual behaviors in Toxoplasma-infected mice. The rodents became hyperactive and groomed less. In 1994 epidemiologist Joanne Webster, then at the University of Oxford, observed that rats harboring tissue cysts behaved differently from their uninfected counterparts. Instead of fleeing from cats, the infected rodents moved toward them—making them easier prey.
Webster suspected that this “fatal feline attraction,” as she called it, was a crafty way for the parasite to get back into a cat’s belly to complete the sexual stage of its life cycle. In the years to follow, this idea gained ground: a large body of work now shows that the parasite can indeed manipulate rodents’ behavior by altering neural activity and gene expression.
Several well-controlled experiments have shown that although uninfected rodents avoid areas that have been infused with cat stench, infected rodents do not seem to mind. Even more bizarre, in 2011 neuroendocrinologist Robert Sapolsky of Stanford University, molecular biologist Ajai Vyas of Nanyang Technological University in Singapore and their colleagues found that—at least in terms of neural activity—infected rats appeared to be sexually attracted to cat scent.
In the mammalian brain, the “defensive” and “reproductive” neuronal pathways run in parallel. These pathways start at the olfactory bulb, involved in odor detection, and ter-minate at the limbic system, an area critical to basic reactions such as fear and arousal. Their proximity may partially explain how the parasite manipulates rodent behavior. . .
Sorry for the belated posting. Miss Molly had to go in to the vet, who removed two teeth. (Maine Coon cats tend to have dental problems. One good thing about British Shorthairs: very few health issues.)
I used my Wee Scot with the really excellent I Coloniali shaving soap (that uses mango oil). It’s a somewhat thirsty soap, but now I know the drill.
With it, I used the Super Speed TV model—sold only through the TV—and a Swedish Gillette blade. I included the contemporary regular Super Speed in front so you can see the difference: no horizontal grooves.
Three passes to perfection, then a good spray into my palm of Creed Aventus, and that slapped onto my face as an aftershave. A great way to start the day for me, but then Molly was off to the dentist.
She’s back home and resting. Antibiotics for a week.
A bird feeder is nice for birds, of course, but also good entertainment for indoor cats. (Outdoor cats kill birds.)
I had a few bird feeders at the other apartment, and one serious problem is that big birds—jays and pigeons, mostly—would show up, hog the feeder, and chase away the small songbirds.
And then I got the Duncraft feeder shown above. It costs $17, and it’s a jewel of a feeder. As you see, small birds have no trouble eating from it, and sometimes one would actually get inside the feeder and eat there. The larger birds would try to eat from it, but they had no place to stand. They would fly by, trying somehow to tilt their flight to secure food, but it was hopeless (from their point of view).
A great feeder, and it holds almost 5 lbs. of black-oil sunflower seed, enough to feed birds for quite a while.
Filled with seed, it hangs now on the balcony, with some seed scattered on the floor and railing to attract the first feeders. Once word gets out, birds will come regularly so long as feed is provided.
Molly’s going to be so entertained. :)
Scientific analysis in Wired article by Bryan Gardiner:
Take heart feline enthusiasts. Your cat’s continued indifference toward her new Deluxe Scratch DJ Deck may be disappointing, but there is an object that’s pretty much guaranteed to pique her interest. That object, as the Internet has so thoroughly documented, is a box. Any box, really. Big boxes, small boxes, irregularly shaped boxes—it doesn’t matter. Place one on the ground, a chair, or a bookshelf and watch as Admiral Snuggles quickly commandeers it.
So what are we to make of the strange gravitational pull that empty Amazon packaging exerts on felis catus? Like many other really weird things cats do, science hasn’t fully cracked this particular feline mystery. There’s the obvious predation advantage a box affords: Cats are ambush predators, and boxes provide great hiding places to stalk prey from (and retreat to). But there’s clearly more going on here.
Thankfully, behavioral biologists and veterinarians have come up with a few other interesting explanations. In fact, when you look at all the evidence together, it could be that your cat may not just like boxes, he may need them. . .
Maru, the cat in the video above, stars in many short videos and is obviously a wonderful cat. Here’s another Maru vehicle:
Quite an interesting study. Cats, like dogs, use their humans’ responses to gauge the threat level of something new in the environment.
Molly came to sit in my lap, a fraught process that involves much testing and hesitation and tentativeness followed by total relaxation and purring. She usually holds down my arm nearest her hear with a front paw planted firmly on that arm.
But that arm wasn’t available today because I was drinking iced tea. I noted that she then placed that arm-holding paw on the arm of the chair and held it firmly down.
So it wasn’t about holding me down, particularly, it was about wanting a firm support for that paw, presumably so she’ll be able to leap the instant a mouse should present itself present itself.
So I was just sitting there, letting her enjoy the moment (and me as well), and I thought of memes, in this sense.
For those just joining us: Memes, defined in chapter 11 of Richard Dawkins The Selfish Gene and expanded upon in The Blind Watchmaker, are replicators very like genes: basic units of inheritance (though inheritance of culture—things that can be imitated—rather rather than of genes), having offspring with slight variations, and competing for resources, with those most adapted surviving. Evolution really does advance the story: later generations gradually become more complex and environmentally manipulative—for example, single-cell entities (where “cell” can refer to a genetic or memetic context) evolve to multicellular entities (organisms, for life evolution; in meme evolution, one gets meme-clusters: memes that reinforce each other, making the meme equivalent of a biofilm). Memes can combine—nationalism and opera and movies and so on—and, as Dawkins says, their evolution is extremely rapid compared to the evolution of lifeforms; and moreover, the meme, like the gene, is “selfish”: i.e., the meme is not so concerned about the well-being of the human hosts as it is about its own survival and propagation. Memes in that sense can act as a kind of disease that doesn’t quite kill the host and is still adapting toward having a more symbiotic relationship: just as physical illnesses become milder as more benign variants are selected. (A virus that killed instantly the host would not spread very far and thus would quickly die out: natural selection at work.)
The point is: memes evolve rapidly and they are “selfish.” Cf. North Korea.
Given that lifeforms and memes are subject to Darwinian logic, they both will (necessarily) evolve. Since both evolutions are subject to the same laws, it very naturally results that one gets a kind of “convergent evolution,” in which one can find many analogues between lifeforms and meme entities. That is, good evolutionary solutions/strategies will be good in either context, so successful outcomes will have some resemblances. Thus, we naturally enough find many analogues between lifeforms and memeish entities and vice versa.
That means you can look at particular lifeform adaptations and seek their analogues among memes, and vice versa.
Even better… and here’s where the story really begins: you can examine differences between human animals and other animals—those that don’t host memes—and perhaps get an idea of how memes might account for significant differences. It’s the old “How are humans different from other animals?” question, but viewed from a meme perspective: it assumes that any differences of substantial nature are due to memes.
Specifically, I was watching Molly just relax totally with not a thought for tomorrow, and thinking that was what life would be like for a meme-free animal—along with intermittent hunger, fear, pain, etc. But still, when times are good, just enjoy them.
Basically, non-human animals have no drive. They lack ambition. They do not want to leave the world a better place. They do not want to advance the knowledge of their kind, or to become known as a champion of their rights, a protector of their poor (though they may indeed protect the poor/wounded, but they have, I’m sure, no concept of becoming “known” for the deed).
Or, to put it more simply, non-human animals lack memes. We are driven by memes, and the meme “We must advance human knowledge, improve human condition” is a very basic, very primitive meme. Once it became active, it was in effect a meme-factory, kicking off a process that multiplies memes by the millions—thus undoubtedly hastening memetic evolution.
So that’s one difference memes make: ambition. And that’s a big difference.
On thinking further: I don’t think the meme-human situation is like the Puppetmasters. Generally speaking, meme propagation is heavily influenced by what “works” (in whatever context): memes that “work” will spread quickly. They in effect fulfill their promises. (Cf. the rapid spread of the meme-cluster “traditional wetshaving with a DE razor,” for example: that meme-cluster spreads rapidly because its promises are for most fulfilled. If the meme didn’t work, analogous to a virus that sickens its host, it doesn’t propagate very well—certainly not so well as those that do. A country like North Korea is an exception (and a meme-cluster with extraordinarily strong protective memes (analogous to antibodies), but in general, a meme that harms its hosts cannot endure. Or so it seems to date.
So, generally speaking, memes benefit us. Still, there is the puppetmaster aspect: many of those benefits are in the form of memes—meme-currency, as it were—rather than direct animal benefits—because, as we’ve seen, animals do not need much. OTOH, we do now have anesthetic. So it’s not all bad.
It’s a puzzle as to which is in charge, is it not?
UPDATE: It strikes me that we have a nomenclature need—a need that, for all I know, has already been met. We need to be able to refer with a single name the generalization of common structures/adaptations/patterns we find in comparing memes and lifeforms. It’s the word for a particular category or type of evolutionary adaptation when you see examples both among lifeforms and among memes. It’s the general terminology for the specific cases represented by memes and lifeforms.
I say “lifeforms,” but in fact it’s “genes.” But I cannot see genes, so I look at their expression and see the adaptation there. The gene benefits if its physical expression in the lifeform helps the gene’s host (to survive to reproduce).
The analogues are amazing, and we do need those generalized names.