Tarantula brains (or lack thereof....)

[NewTguy]

I have read many times here and elsewhere that tarantulas do not have a brain, cannot think, feel emotions, etc. The little reading I've done on this seems to base this conclusion on physiological data, e.g. organization of nerve clusters and the like, but I don't recall seeing a lot of behavioural studies.

After recently experiencing my T seemingly plan and execute a rather complex escape, I question the holding that they are totally unintelligent. I've also seen many posts where people talk about their T's "feeling stress", exhibiting varying "personalities", even being defiant" (e.g. repeatedly moving something or landscaping the enclosure the way it wants, despite the keeper's efforts to do things differently), which seems to contradict the conventional wisdom that they are just an emotionless, instinct-driven bundle of nerves.

I'm curious, what do other people think? I apologize in advance for any naivety, I certainly don't have any experience in animal physiology/psychology, just basing my thoughts on observation.

 

[Vanessa]

I would never accuse them of being 'unintelligent', but I certainly would not compare their form of intelligence to an animal with a totally different brain structure.
My question always is why does it matter so much to people? Why do people constantly need to find similarities between them and us? Or them and other animals that we feel more comfortable with? Why do we not just let them be what they are, and do the things that they are capable of, without imposing an unrealistic set of guidelines on that behaviour based on our comfort level?
They're spiders. They don't have complex brains like we do. They don't have emotions that we can necessarily relate to. They do spider things for spider reasons. Sometimes those spider behaviours are going to resemble non-spider behaviours, but that doesn't mean that they have non-spider capabilities. It just means that they engage in behaviour that resembles other animals that we are more comfortable with and can more easily relate to.
Yes, we are learning things every day and we haven't learned all we can about spiders. However, science does have a pretty decent grasp of ganglia and how they work... even how they work compared to our more complex brains. I would honestly start your quest at the biological level first and understand the limitations that they have due to their physical structures. That would go a long way to equip you with being able to recognize their behaviour for what it is.

 

[Polenth]

Spiders can learn and remember. They have personalities. The problem is that conventional wisdom and common knowledge are often outdated. The idea that a central big brain is needed for everything is one of those things that has turned out not to be true. Plants can learn and they have nothing resembling an animal brain.

The way they think is going to centre around things spiders do, like finding a route to prey and catching that prey. Just don't take it to the point of assuming your spider loves you want wants to hear your guitar playing.

 

[Stratton]

This is actually something I work with. I've spent some time observing tarantula habits and behavior and even used them as the focus for my PhD work.
So, yes they do not possess an advanced brain structure like you would see in vertebrates like dogs or apes or something. Their brains could best be described like that of a robot's or a better analogy would be like comparing your current computer that you are using right now with that of a Commodore 64. Your current computer could be an example of let's say your brain, being able to do multiple functions, planed tasks and high levels of programming, graphics and computing abilities all at the same time.
A tarantula's brain is a lot like a Commodore 64 in that it is very simple when compared to a current computer. Their brains are very stimulus driven or command orientated, they will sit and wait for stimulus of one kind or another and then act on it. So let's say your T. is in an exposed area with a lot of light, the light stimulus with the lack of cover or having something touching or close to your T. will make it want to find safety or a hide. It will search for cover of some kind like a hole in the ground. It will try and get in the hole but if it is too small it will dig the hole out and make a burrow, lay silk and all that spider like stuff. So a series of complex actions driven by a single stimulus or situation, like the Commodore 64 their brains can handle complex problems (To a degree mind you, I mean like solving big math problems really fast) but they don't make future plans or do more than the few things at a time. They could probably handle Pong but there would be no way they could handle Fortnight.
All that being said it is still worth mentioning that their brains are more advanced than the average invertebrate's. They run on a lot of instinct but have shown that they can adapt and have a rudimentary memory. They'll never remember who you are but they will remember that food tends to land in a certain area for example. As far as feelings go, they don't have them, they lack the part of the brain that produce emotions. In fact, all invertebrates do. This doesn't mean that you can't get moody tarantulas, a mood and emotions are different things. Aggressive versus docile are moods because they are based more on environmental and physical stimulus than emotional or psychological. Think, if someone called you fat with a smile and calm voice, that would register on an emotional level while if someone came up and hit you, that would be physical. You would become defensive at the hit and emotional at the comment. (In general and as examples)
So tarantulas aren't stupid, brainless things wandering about. They are more driven by instincts and stimulus but they use that stimulus and their senses to act on a situation more than most other invertebrates but still far less than most vertebrates.

 

[boina]

I absolutely hate the computer analogy and think it's wrong on a fundamental level. Computers don't learn and adapt, tarantulas do. Every animal does. It's a basic survival function. They learn where the food comes from and where the water is, how their environment is structured, what stimuli are common and safe (e.g. can adapt to street noise and car vibrations or common foot steps), and what stimuli are new and different and may therefore indicate danger. They learn different smells and may actually be able to differentiate the smell of their owner from different people. That doesn't mean they recognize their owner, but that they know: common smell = safe, new smell = may be dangerous. (I made some experiments to this when I participated in arachnophobia training: my E. sp. red would easily walk onto my hand, but always hesitate before walking onto an unknown hand).

They also "feel" stress. Stress and stress hormones have been researched quite extensively in invertebrates (especially roaches) and there is no reason to think that tarantulas will be different.

they lack the part of the brain that produce emotions.

That's another thing that's wrong on a fundamental level. Just because they lack the part of the brain than produces emotions in vertebrates doesn't mean that they may not have something else to produce emotions - very different structures may have the same functions in other animals. I'm not saying tarantulas have emotions - there's no evidence for that - I'm just saying that argument is fundamentally wrong. However, tarantulas most certainly "feel" fear or an equivalent of it, because again, fear, or something similar, is a basic survival trait. If you don't fear you are dead the first time you meet something dangerous. You don't need a brain for that, all you need is hormones and some cells with hormone receptors, and tarantulas most certainly have those.

 

[AphonopelmaTX]

They learn where the food comes from and where the water is, how their environment is structured, what stimuli are common and safe (e.g. can adapt to street noise and car vibrations or common foot steps), and what stimuli are new and different and may therefore indicate danger.

The tarantulas that live in the public parks near where I live would disagree with being able to get used to footsteps. You would think they would recognize footsteps as harmless after decades of being exposed to it, but I still can't sneak up on them.

Kidding aside though. I wish more people had the opportunity to observe tarantulas in their natural environment. Observing tarantulas in nature, one will quickly see that there is quite a bit of problem solving going on in their day-to-day lives. Especially by males in the mating season. The most fascinating aspect of tarantula behavior is watching a male navigate terrain to find the burrow of a female sitting several yards away from it. I even tried to displace one from its path one year but it somehow found its way back to its original path. Maybe in that instance it was just following chemical cues, but I swear it was following a mental map of its surroundings. That male tarantula sure did appear to know where it had been and where it needed to go.

Key elements of tarantula behavior, their capacity for problem solving, and memory is completely lost when making conclusions based only on observation in captivity. Without learning how they interact with their natural environment, there is nothing to compare with in captivity.

 

[Stratton]

I absolutely hate the computer analogy and think it's wrong on a fundamental level. Computers don't learn and adapt, tarantulas do. Every animal does. It's a basic survival function. They learn where the food comes from and where the water is, how their environment is structured, what stimuli are common and safe (e.g. can adapt to street noise and car vibrations or common foot steps), and what stimuli are new and different and may therefore indicate danger. They learn different smells and may actually be able to differentiate the smell of their owner from different people. That doesn't mean they recognize their owner, but that they know: common smell = safe, new smell = may be dangerous. (I made some experiments to this when I participated in arachnophobia training: my E. sp. red would easily walk onto my hand, but always hesitate before walking onto an unknown hand).

They also "feel" stress. Stress and stress hormones have been researched quite extensively in invertebrates (especially roaches) and there is no reason to think that tarantulas will be different.



That's another thing that's wrong on a fundamental level. Just because they lack the part of the brain than produces emotions in vertebrates doesn't mean that they may not have something else to produce emotions - very different structures may have the same functions in other animals. I'm not saying tarantulas have emotions - there's no evidence for that - I'm just saying that argument is fundamentally wrong. However, tarantulas most certainly "feel" fear or an equivalent of it, because again, fear, or something similar, is a basic survival trait. If you don't fear you are dead the first time you meet something dangerous. You don't need a brain for that, all you need is hormones and some cells with hormone receptors, and tarantulas most certainly have those.

You're anthropomorphising them and you don't seem to understand what a comparison and an analogy are. I was speaking from an educated standpoint as someone who has observed and researched tarantulas in the field and in the lab. Basically if you don't have lobes in your brain and a large amygdala, you can not have emotions beyond simple, evolutionary responses like fear or stress. A tarantula's brain does not produce serotonin, endorphins, oxytocin or dopamine, so they can not have emotions such as love, happiness or gratitude. If you like I give you a list of reading materials on the subject so you can make an informed comment on the subject next time instead of an opinion.

The tarantulas that live in the public parks near where I live would disagree with being able to get used to footsteps. You would think they would recognize footsteps as harmless after decades of being exposed to it, but I still can't sneak up on them.

Kidding aside though. I wish more people had the opportunity to observe tarantulas in their natural environment. Observing tarantulas in nature, one will quickly see that there is quite a bit of problem solving going on in their day-to-day lives. Especially by males in the mating season. The most fascinating aspect of tarantula behavior is watching a male navigate terrain to find the burrow of a female sitting several yards away from it. I even tried to displace one from its path one year but it somehow found its way back to its original path. Maybe in that instance it was just following chemical cues, but I swear it was following a mental map of its surroundings. That male tarantula sure did appear to know where it had been and where it needed to go.

Key elements of tarantula behavior, their capacity for problem solving, and memory is completely lost when making conclusions based only on observation in captivity. Without learning how they interact with their natural environment, there is nothing to compare with in captivity.

I spent 4 years observing and documenting wild tarantula behavior and habits including areas such as Nicaragua, Costa Rica, the American Southwest, Brazil, Venezuela, various parts of Africa and Asia. I wanted to go to Australia two years ago but there was a department funding issue so we had to cancel the expedition.

 

[50centipede]

Human emotions and feelings... IMO highly overrated.

 

[Polenth]

You're anthropomorphising them and you don't seem to understand what a comparison and an analogy are. I was speaking from an educated standpoint as someone who has observed and researched tarantulas in the field and in the lab. Basically if you don't have lobes in your brain and a large amygdala, you can not have emotions beyond simple, evolutionary responses like fear or stress. A tarantula's brain does not produce serotonin, endorphins, oxytocin or dopamine, so they can not have emotions such as love, happiness or gratitude. If you like I give you a list of reading materials on the subject so you can make an informed comment on the subject next time instead of an opinion.

It is an opinion that there is only one way for emotions to be produced, that a brain is required for those functions, and that the brain must work like a vertebrate's brain. People not sharing that opinion with you is not about lack of scientific knowledge. It's about looking at current knowledge and seeing that it's inadequate.

I like to bring up plants because they do things people always said they couldn't without a brain and scientists have very few answers about how this is possible. The thing I learnt from studying science is we really know nothing compared to all there is to know. The things we do know are not proof that nothing else exists outside of those observations. So, we can know how a mammal brain does something, but this is not proof that this is the only path to that function.

 

[Vanessa]

It is an opinion that there is only one way for emotions to be produced, that a brain is required for those functions

Sorry, but can you please provide any factual information to back up your claim that the forming of emotions does not require a brain?
I think what is happening here is that spiders engage in certain types of behaviour that resembles behaviour in other animals who are capable of more complex emotions.
People are mistaking that resemblance as meaning that spiders must posses those emotions to perform those types of behaviour as well.
That is not accurate.

 

[boina]

You're anthropomorphising them and you don't seem to understand what a comparison and an analogy are. I was speaking from an educated standpoint as someone who has observed and researched tarantulas in the field and in the lab. Basically if you don't have lobes in your brain and a large amygdala, you can not have emotions beyond simple, evolutionary responses like fear or stress. A tarantula's brain does not produce serotonin, endorphins, oxytocin or dopamine, so they can not have emotions such as love, happiness or gratitude. If you like I give you a list of reading materials on the subject so you can make an informed comment on the subject next time instead of an opinion.

I'm a biologist with a Ph.D. in molecular- and microbiology, and a Master's degree in animal behaviour. Keep your insults to yourself. I've never talked about love, happiness, or gratitude. Try reading the post you answer to. I've explicitely said there's no evidence for tarantulas having emotions. I've only talked about exactly the simple, basic emotions you mentioned, fear and stress.

And about the neurotransmitters you mentioned:
Octopamine = invertebrate neurotransmitter related to norepinephrine.
There's further GABA and glutamate as neurotransmitters in invertebrates and several more. Just look it up.

No, tarantulas don't have the same neurotransmitters as vertebrates. They don't have the same heart or the same kidneys or the same eyes and still structures that function equivalently. How the hell do you come to the conclusion that invertebrates need exactly the same neurotransmitters for the same functions as vertebrates? That argument is idiotic. They don't have the same digestive enzymes either, and they still digest.

Again, I don't claim that tarantulas can feel love or anything the like, I think it's highly improbable, because we've never seen signs of it and it wouldn't make sense evolutionary, but your argument is simply not logical.

A tarantula's brain does not produce serotonin, endorphins, oxytocin or dopamine,

Ok, I did some reading. Serotonin is actually an evolutionary conserved neurotransmitter that does get produced by all arthropods ever investigated, and even by molluscs and plathelmints. There's also this interesting article about dopamine in behavioural modification of crickets. You were factually wrong.

And in the end there's this. Yes, invertebrate brains produce even oxytocin, the "love" transmitter. From the article:

"We begin by tracing the evolution of oxytocin through the invertebrate animal lineages, and then describe common themes in invertebrate behaviors that are mediated by oxytocin-related peptides, including reproductive behavior, learning and memory, food arousal, and predator/prey relationships."​

Do some fact checking next time before you start insulting people. You never know who may actually be able to question your statements.

 

[MintyWood826]

Sorry, but can you please provide any factual information to back up your claim

But what about you? I haven't seen anything in this thread that factually proves that there is no possible way at all for emotions to happen without a brain ever, sorry.

 

[Bob Lee]

I have read many times here and elsewhere that tarantulas do not have a brain, cannot think, feel emotions, etc.

They for sure don't have a brain, they have ganglia.

 

[Feral]

In addition to what's already been said...

Science has learned, especially in the last two decades, that organisms don't necessarily need the same equipment to do the same or similar things as mammals and reptiles (including birds) and amphibians and so forth. Invertebrates don't have convection lungs and diaphragms and hemoglobin and whatnot, but they oxygenate, yeah? They just have a different system, like tarantulas have diffusion lungs and hemocyanin and whatnot and they get the job done just fine. Just as true in other systems, like the nervous system. Invertebrates' nervous systems are just as alien, and seem so absurdly tiny to us (check Haller's law, though), but we're learning more and more about what they can do. For instance, we've recentlyish found insects to have no nociceptors or any similar structures to experience pain, but instead of assuming that they are therefore of incapable of feeling pain, we looked to see if they're was an alternative pain-detecting system in place... and found one! It's entirely different, but it's there and was waiting to be discovered as soon as humans realized there's not just one way for things to get done. After that discovery, we've found that prolong sensitization of a wound/chronic pain in insects is a definite thing, too! We kind of have to concede that the human experience of pain may or may not differ to the invertebrate experience of pain, since it's the apples and oranges of two different systems, but we know the experience is bad and no creatures likes it.

We're also discovering, because of Haller's law, just how much more tiny "brains" are capable of than we ever thought. We're beginning to document inverts being able to do amazing things, like wasps being able to recognize every individual wasp face in their colony, and complex behaviors despite the fact it seems to us lay people like they wouldn't have two brain cells to rub together. (Ah, mixed metaphors! ) So I don't know that I'd go as far as to say they experience emotions, not the same as humans know them at least, but who knows what else we'll discover in the future about those little alien nervous systems?

 

[AphonopelmaTX]

Ok, I did some reading. Serotonin is actually an evolutionary conserved neurotransmitter that does get produced by all arthropods ever investigated, and even by molluscs and plathelmints. There's also this interesting article about dopamine in behavioural modification of crickets. You were factually wrong.

And in the end there's this. Yes, invertebrate brains produce even oxytocin, the "love" transmitter. From the article:

"We begin by tracing the evolution of oxytocin through the invertebrate animal lineages, and then describe common themes in invertebrate behaviors that are mediated by oxytocin-related peptides, including reproductive behavior, learning and memory, food arousal, and predator/prey relationships."​

Do some fact checking next time before you start insulting people. You never know who may actually be able to question your statements.

Then there is this article that discusses the change in monoamine levels from agonistic behavior in male Aphonopelma hentzi. So, I'm a little confused as to why it was stated tarantulas don't produce serotonin, endorphins, oxytocin or dopamine. It is the supraesophageal ganglion that produces those neurotransmitters.

Punzo, F., & Punzo, T. (2001). Monoamines in the brain of tarantulas (Aphonopelma hentzi)(Araneae, Theraphosidae): differences associated with male agonistic interactions. The Journal of Arachnology, 29(3), 388-396.

 

[boina]

Then there is this article that discusses the change in monoamine levels from agonistic behavior in male Aphonopelma hentzi. So, I'm a little confused as to why it was stated tarantulas don't produce serotonin, endorphins, oxytocin or dopamine. It is the supraesophageal ganglion that produces those neurotransmitters.

Punzo, F., & Punzo, T. (2001). Monoamines in the brain of tarantulas (Aphonopelma hentzi)(Araneae, Theraphosidae): differences associated with male agonistic interactions. The Journal of Arachnology, 29(3), 388-396.

Thank you for posting this! Super interesting.

 

[Vanessa]

But what about you? I haven't seen anything in this thread that factually proves that there is no possible way at all for emotions to happen without a brain ever, sorry.

Start with an easy one here: How Emotions are Made

"Emotions are created by our brain
Neuroscience research in past decades has shown that emotions do not have ‘fingerprints’ in the brain. Different networks in the brain can create the same emotion. And yes, emotions are created by our brain. It is the way our brain gives meaning to bodily sensations based on past experience. Different core networks all contribute at different levels to feelings such as happiness, surprise, sadness and anger."

 

[Feral]

I guess I would be at fault if I did amend my post to include:

Having said all that I did, I think anthrpomorphisms are very detrimental. And I think swinging the opposite direction to assuming the absence of any intelligence or emotional capacity that actually is, in fact, present (whether we know it or not) can be equally as detrimental. I think the only way we can provide the best care for these creatures is to try to understand them how they actually are, not as we think they are or want them to be. (To care for the tarantula, you must BE the tarantula. lol) I concede that can be difficult, but I think sharing science-based information and discussions like these amongst hobbyists are a wonderful step forward!

 

[Vanessa]

The thing is, I don't think that people are being entirely honest about what they're really asking in these threads, what information they are really challenging. You can tell by the wording of the question and the examples being given in the original post... and they are not much different to the dozen previous posts of the same topic that have ended up the exact same way.
These posts aren't challenging whether or not a ganglia is capable of creating a more emotion-like response than science originally thought. Whether fear is an emotion or an instinct. Whether a ganglia is capable of chemical reactions.
These posts are specifically asking if tarantulas are currently able to perform cognitive tasks that are not associated with a ganglia system, but are limited to brains with a far different structure.
A tarantula doesn't like you, or hate you; they do not develop an attitude that would result in them becoming defiant towards you; they do not associate you with being a non-threat; they don't enjoy your company; and they aren't even capable of being docile, or aggressive. All of those attributes require a certain amount of reasoning that they are just not capable of.
I also suspect that these questions often coming on the tail end of another heated thread about handling is not a coincidence, either.

 

[EtienneN]

Going on the shoulders of @Vanessa and @boina 's posts about scientific consistency and empirical studies, I think there is a very human trait to find patterns in things that aren't meant to have a pattern to them. Like we evolved to be good problem solvers so our brains automatically pick up on information that forms a 'just-so' pattern; (i.e. the conclusion leading the evidence) This is detrimental because we then categorise things in whatever labeled bins are in our minds. This spills over to all aspects of life and thus people find patterns in their pet's behaviours and interpret it as they 'perceive' the (faulty) pattern.

I'm all for researching tarantula behaviour. But I think we need to frame it from a perspective of having zero expectations. I.E. don't form your conclusion before you've done your abstract and experimentation. If octopuses can be smarter than some dogs then tarantulas can definitely have personalities.

Also; sometimes it's okay to just say "We don't know."