Mind-controlling parasite makes hyena cubs more reckless around lions | Hacker News Reader

Mind-controlling parasite makes hyena cubs more reckless around lions

nationalgeographic.com

111 pointsawb61 comments

This is about toxoplasmosis. It is also known to increase the odds that an infected rodent will get itself eaten by a cat:

Infection with T. gondii has been shown to alter the behavior of mice and rats in ways thought to increase the rodents' chances of being preyed upon by cats.

https://en.wikipedia.org/wiki/Toxoplasmosis

It can infect humans. It may be a risk factor for schizophrenia, OCD, bipolar disorder and other mental health issues. The evidence seems inconclusive at this time.

The change of rat behavior seemingly being based on inverting rats' aversion to cat odors into developing an actual attraction for them [0].

Robert Sapolsky's work is an abundant resource on the topic[1].

[0] https://www.pnas.org/content/104/15/6442

[1] https://scholar.google.de/scholar?hl=en&q=sapolsky+toxoplasm...

It's not that black or white though, more than 60% of the World population has been infected with Toxoplasmosis, yet you don't see people running towards lions at every corner.

The path how the parasite infects rodents, then cats, then humans is very complex and not at all consistent, most articles on the Internet dumb it down way too much.

This Youtuber has an awesome explanation on it: https://www.youtube.com/watch?v=rdlHNhrMw-A

Also, his channel is translated from Hungarian, it's an awesome channel btw.

> yet you don't see people running towards lions at every corner.

The headline says more reckless.

I wouldn’t consider it a stretch to say some people are definitely more reckless. Whether there’s a causal link, I couldn’t say.

There's a theory that toxoplasmosis, given it can transfer from cats to humans, is the reason for the 'crazy cat lady' stereotype. Certainly, cat owners I've known seem more likely to have 'attacks' of extreme aggression than the general population, and giving vent to that does seem like a 'risk' to our status in the community that most of us don't take. Then again, having that sort of temperament may make someone more suited to owning cats than other pets...

The article described something specific that could be tested. I leave it to the scientist to design a similarly specific experiment for humans. Also the "reckless" behaviour exhibited by the cubs disappeared after there were older than 1 year:

While uninfected cubs stayed an average of 300 feet away from lions, cubs that had Toxoplasma antibodies in their blood had ventured within an average of 142 feet from the predators, a dangerous proximity. These differences disappeared after the cubs turned one, perhaps because the survivors learned not to get too close to the felines.

so those infected survivors got much closer than the healthy ones and yet survived. Sounds like a [harsh] filter for the high survivability traits which may be beneficial for the population, and that may explain why the [susceptibility to the] infection hasn't been selected out.

Possibly, but luck isn’t an inheritable trait.

It is in humans.

... according to Larry Niven.

And Rockefeller, Cargil, Rothschild ...

What makes you think there was inherited luck involved?

People make their own 'luck'.

Luck and Inherited Luck are different things.

Yes.

> [...] which may be beneficial for the population, [...]

Do keep in mind that evolution mostly works on the level of genes, and perhaps individuals. It doesn't really work on the level of the population.

See eg https://en.wikipedia.org/wiki/Group_selection

> yet you don't see people running towards lions at every corner

Oh, but you do see people running towards cats! They keep them indoors and feed them.

Perhaps in more complex organisms there is a more complex response to the pathogen? It could trigger any number of maladaptive behaviors in humans and it would be hard to know if it was the parasite or one of the many other unfortunate environmental factors of the modern world.

It might even trigger adaptive behaviours.

Toxoplasma is dormant in humans.

What is really interesting – how human toxoplasma prevalence varies per country.

I remember an Australian study that showed a significant increase in the likelihood of men with toxoplasmosis to be involved in car accidents. There was also something about women being more promiscuous when infected. I doubt the study had proper controls, so don't take it too seriously, but i would be surprised if toxoplasmosis had no effect on the human hosts behavior.

Racing drivers should be tested for toxoplasmosis.

I had toxoplasmosis and I drive a bit on the aggressive side.

The Economist ran a piece some years ago claiming a link between countries with reckless driving habits and high rates of toxoplasmosis in the population (pointing to France as an example): https://www.economist.com/science-and-technology/2010/06/03/...

Trematodas are really interesting too https://www.newscientist.com/article/2129880-parasite-living...

Similarly, there is a flatworm parasite that takes over a snail's mind, turns its eyes into colourful pulsating beacons to attract predator birds to eat it, parasitizes the bird, and then leaves its eggs in the bird poop for more snails to eat later.

https://en.m.wikipedia.org/wiki/Leucochloridium_paradoxum

National Geographic video (warning, kinda gross): https://m.youtube.com/watch?v=Go_LIz7kTok

There's also:

- cordyceps fungi that cause ants to climb to high branches and clamp their jaws to them before dying so the fungus' can sprout out of their heads: https://www.nationalgeographic.com/animals/article/cordyceps...

- Anomotaenia brevis: a tapeworm that causes ants to live unnaturally long lives and emulate the queen ant's pheromones causes the colony to expend energy feeding the infected ants at the expense of the rest of the colony: https://en.wikipedia.org/wiki/Anomotaenia_brevis

And for another plain gross entry: a tongue-eating louse that eats and takes the place of a fish's tongue. I guess it gets to eat when the fish eats? https://www.nationalgeographic.com/science/article/tongue-ea...

Makes you wonder if some kind of CO2-loving parasite isn't infecting humanity...

You could consider human self-awareness a kind of parasite that feeds on convenience.

It's called capitalism :)

When communism fell in East Germany, pollution actually dropped for a while as living standards rose, because a lot of inefficient coal plants were replaced.

Are you suggesting that carbon emissions do not exist outside of countries that have private ownership of production?

These "chipization" conspiracies suddenly start looking more creepy. Imagine some controlled (or uncontrolled) infection indeed can cause humans to take some specific risky behaviors. For example, gambling or taking more credits.

or some parasite that makes us believe everything is a system, spot patterns everywhere, and approach all "problems" with systems thinking, when reality is just chaos.

Reality being chaos would be systematic, too.

Wheat has been pretty successful in domesticating humans, so far.

Totally unrelated (or perhaps due to a parasitic conspiracy idk) Dave Aitel an infosec policy influencer just started a company by the name of cordyceps. First time I heard of it in nearly 50 years of my life was reading his twitter, now it pops up on this timeline few days later.

https://twitter.com/daveaitel/status/1410308330808135691

One thing about mind controlling parasites that's bugging me is that we only ever hear about the extreme cases when it's very visible because the host does something counter intuitive from an evolutionary point of view. But statistically there must be many more cases where the effect of the mind control is just partial, not evolutionary suicide or even beneficial.

How spread is this phenomenon really? How many generations does it take for a parasite to evolve into such spectacular effect? Where are the non spectacular mind controlling parasites and how are they influencing their host?

Is there a disease that makes us love cats - https://news.emory.edu/stories/2016/07/esc_loving_cats/campu...

It might not hit the news, but people are looking into things like how gut microbacteria might affect your brain and behaviour [1]. From what I can see it looks like it is more and more accepted that microorganisms affect us in many different ways.

[1] https://icds.uoregon.edu/wp-content/uploads/2011/07/CryanDin...

I was going to mention sugar-loving fungi in our gut causing sugar cravings. Fascinating to think about next time my sweet tooth acts up.

I wonder what would happen if you made candy with some antifungal compound, maybe it would reduce the craving for sugar..

Xyletol sort of works that way, it looks like sugar to (at least some of) the micro-organisms that like sugar but contains nothing nutritious to them.

Not sure if one can separate the effect prolonged xyletol substitution has on the microbiome from the effect it has on the actual human portion of the metabolism, if one replaces any addiction with something else the original cravings will subside over time.

There is a theory that colds and flu and many sexually transmitted diseases also affect behaviour enough to encourage more spread. In other words, it's possible that being infected with an STD makes you more sexually active.

It's a theory as it's incredibly hard to do studies about. The main study this was based on was done on people with the flu - they used students who had the flu jab (mild flu effects etc) - and saw that those students went out more and socialised. Subsequent studies think this might be because they felt more protected being jabbed, rather than the virus affecting their behaviour.

I read somewhere (from an Atlantic article several years ago) that soon before death, AIDs patients would feel a stronger desire to copulate.

How spread is this phenomenon really? How many generations does it take for a parasite to evolve into such spectacular effect, where are the non spectacular mind controlling parasites and how are they influencing their host?

Maybe this is where we will find consciousness, we're just mobile meat based storage for parasites to hang out in...

I really know very little about this, but I sometimes imagine my body as a society of microbic life, with my mind being a pseudo-democratic governing body. It's an interesting perspective, were you essentially are responsible for the well-being and perseverance of your billions of law abiding micro-citizens.

There are plenty of pop-sci articles about how the microbiome seems to be influencing our nervous system in a multitude of ways. So the microbes may actually have a way to "vote" in my analogy.

There is certainly lots going on inside, loads of areas of study at the monment look at gut-brain axis (GBA) and stuff like 'Gut bacterial taxonomic abundances vary with cognition, personality, and mood in the Wisconsin Longitudinal Study' https://www.sciencedirect.com/science/article/pii/S266635462...

'Highlights • Multiple families, genera, and species were associated with psycho-cognitive traits.

• Megamonas is associated with cognition, mood, and personality.

• Pseuroramibacter_Eubacterium is associated with mood and personality.

• Fusobacterium is associated with personality and cognition.

• Butyrivibrio is associated with cognition.'

Edit: just to add I'm a layperson so not able to asses the quality of this study, if someone is more able to do that I would welcome the input.

As it's an axis I'd be interested to know if there are any studies looking at effects in the other direction, can our brain modulate the presence of the gut bacteria in some way, it would seem that for a beneficial symbiosis communications may run both ways?

For those who want to read a whole book on the topic of the influence of a variety of parasites on behavior, you might read "This Is Your Brain on Parasites: How Tiny Creatures Manipulate Our Behavior and Shape Society" by Kathleen McAuliffe. It also discusses whether or not there are "parasites" that shape behavior in ways that are beneficial to the host. Also, my GR review of it: https://www.goodreads.com/review/show/1707114701

I hate the term "mind control". It anthropomorphises these weirdly evolved behaviours. Yes it is gross / weird / unsettling that our minds can be affected in ways they don't notice (wait till we see what humans get up to post 2060) but it is not intentional in the way we understand it.

For example we don't think Ebola intentionally causes bodies to necrotise so much they infect everyone around them but that's what happens.

There are more

While the neurological reprogramming of complex behavior is well documented even among earthly parasites (see Dicrocoelium; Entomophthora; Holy See; Sacculina; Toxoplasma; others), it should be emphasized ...

My speculation is that most of the wars and violence in the world is due to cats... well, toxoplasmosis in people's brains, which came from cats.

Why toxoplasomosis is getting trendy suddenly? I've just read another article on this that was trying to scare people, obviously without any merit [0]. Is some company creating vaccine for this and needs some marketing?

The first comment says "It may be a risk factor for schizophrenia, OCD, bipolar disorder and other mental health issues. The evidence seems inconclusive at this time. "

Yes, it can cause all those horrible things (I think that only autism is missing on the list), only there is no proof for that, but, nowadays, who cares if the story fits twitter size post and has a chance to get "viral".

[0] https://news.ycombinator.com/item?id=27615857

Yes, I’ve noticed several articles in the past week on the subject. The resurgence of this topic has me looking for a presentation I watched perhaps 5-10 years ago where the presenter suggested humorously that the Victorians popularized and normalized cat pet ownership at the level we now know (having cats indoors) because they were afflicted with toxoplasmosis. The presenter suggested that icanhazcheeseburger and pictures of cats on the internet are a symptom of mass infection of people with toxoplasmosis and that people who are infected are more likely to give comfort to crying cats which have learned, or had their behavior modified by the parasite, to mimic the cries of human babies.

If anyone can find me this presentation I’d be grateful. I fear a pro-cat conspiracy drove this video off the internet.

> Is some company creating 'product' for this and needs some marketing?

That would be my first candidate, yep. A problem with this is the disconnection between effect and cause. The startup could be lying to themselves and entering in a greyhound race trying to develop a solution for a problem that was not the problem that they though it was. There is a risk that the final product will have a really short life (and makers hate to be told that). "Ozone machines against Covid" came to my mind for example.

Blind faith towards bad (or biased) science is a problem.

Is like discovering that people drunk with severe headache drive reckless and are more prone to have accidents at work and "all had drive licenses", and concluding that "people with drive licenses are worse drivers than people without; we have another publication".

Sorry, but this is not "creature is mind-controlling me", is "my brain is on fire" (and my experiment design could be better).

In the experiment the hyaena cubs supposedly move closer to lions. Maybe the cubs are just uncomfortable and trying to find a relief instead to defying lions?. Are the same ill cubs moving more far away from lions also?. I would want to see the Standard deviation for distances, and a control group in the articles related with predator urine to discard just an increase in wandering searching for water.

Are this cubs moving toward water sources where lions gather?

Are this cubs looking for a more shadowed spot where lions rest?

This kind of studies precooked to produce the desired answer while ignoring the, more probable, but non publishable and less sexy explanations border pseudosience. Extreme claims require extraordinary solid proofs, not tabloid style management.

For 600th time... Toxoplasmosis is NOT a "mind controlling" parasite. Ill animals are preyed more often than healthy animals. THIS IS NORMAL. Because they are ill (and predators have an essential role as cleaners of ill animals).

If a bullet hits somebody (non-fatally) in the head, a common outcome is the behavior of this person changing forever. The bullet is not remote mind-controlling them from the drawer of the physician; It has caused some brain damage that is a different concept. Toxoplasmosis does exactly the same. It causes a brain damage in the cub, so they are more vulnerable.

Yeah, the closest most people here have been to a mind controlling parasite is Facebook.

Given how effective natural selection is for selecting surviving traits, why are you so sure that a parasite can't have some level of behaviour altering effects? Sure, it's probably not an inner monologue telling the hyena where to go, but it does appear that infected animals are either more reckless in general, or less cautious when faced with lions specifically - a behaviour which helps the parasite reproduce.

Do you have any sources for your claim that that toxoplasmosis doesn't have any behaviour altering effects?

https://en.wikipedia.org/wiki/Moving_the_goalposts

https://en.wikipedia.org/wiki/Russell%27s_teapot

Agreed, the conclusions about mind control or altered behaviour are unsupported by the observations. For example, hyena cubs with the parasite getting closer to lions might simply be due to worsened sense of smell or vision, or less attention due to pain etc. ... We unfortunately live in a time where science profits from sensationalist speculation.

https://pubmed.ncbi.nlm.nih.gov/26859275/

That's an incredibly weak straw man that you've built there.

Toxoplasmosis has been shown to alter the behaviour of prey species in such a way that they become attracted to the urine of members of predator species - and this attraction significantly improves toxoplasmosis' chance of reproduction.

The "mind control" is very limited - but when a sick animal pretty much ends up programmed to dive into a predator's mouth "THIS IS NORMAL" could not be further from the truth.

Maybe fungi, which turn ants is zombies, is also part of some sick fiction... except that is true. The world is full of evil biological schemes. And toxoplasmosis is one of the most widely spread mind-control on this planet.

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