Why do tarantulas get so stumped by feeders playing dead?

Moakmeister

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We've all seen it: you drop a big juicy roach right in front of your tarantula, and the roach plays dead, acting like nothing more than a rock. The tarantula is unable to realize that food is there, so it doesn't attack. You have to nudge the roach to get it to move again.
Wait, what?
Any knowledge about tarantulas indicates that they should never be fooled by this trick. Tarantulas sense their environment with their hairs all over their legs. They feel the vibrations going through the ground and in the air, and they can tell where something is and how big it is. So when the roach lands on the ground, they KNOW something is there. Sometimes, the tarantula will actually turn around and touch the roach, and they still don't attack. Even if they think it's just a stick or a rock, can't they at least poke at it to see if it moves? And furthermore, can't they smell the roach? Don't they taste with their feet? How do they not realize it's food when every single sense is telling them it is?
 

AphonopelmaTX

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I see this every time I feed dubia roaches and the only hypothesis that I can come up with is that they can't actually smell or taste the roach using their chemoreceptive hairs and that movement is the primary and only way they can detect them.

Using all 8 of my most aggressively feeding tarantulas comprising all three Theraphosa species at different instars from mature females and males to immatures, they all do the same thing. Drop the roach in, spider pounces, roach freezes, spider acts confused like it lost where the roach is even with it standing on top of it. As soon as the roach twitches even the slightest bit, the giant spider(s) then pick it up with its chelicerae and starts chewing on it.

I haven't done any actual experimenting on this using the same spider(s) but I couldn't help to notice that my very small (2nd or 3rd instar) Aphonopelma sp. "Diamondback" will eat small dead crickets. They obviously can smell it as the dead crickets are carefully placed on the opposite end of where they sit at the time of feeding. Contrast to a small dead dubia roach I've given other small tarantulas (I can't remember which species though), and they never found it. The same situation though plays out time and time again with my adult Theraphosa spp. I use male dubia roaches as feeders since they run about, but large juvenile dubia roaches play dead and my spiders lose them until they move again.
 

dopamine

Arachnobaron
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Crickets pull this crap too (although not nearly as bad) and it irritates me to no end. I feel your frustration.
I usually drop the roach right in front of the T, hoping it'll land on its back, for this reason as it produces a better feeding response and limits the chance for the prey to freeze and play dead.
Another option is to simply pre kill and place the roach soft side up, by the T or near it's burrow.
 

Trenor

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I see this every time I feed dubia roaches and the only hypothesis that I can come up with is that they can't actually smell or taste the roach using their chemoreceptive hairs and that movement is the primary and only way they can detect them.

Using all 8 of my most aggressively feeding tarantulas comprising all three Theraphosa species at different instars from mature females and males to immatures, they all do the same thing. Drop the roach in, spider pounces, roach freezes, spider acts confused like it lost where the roach is even with it standing on top of it. As soon as the roach twitches even the slightest bit, the giant spider(s) then pick it up with its chelicerae and starts chewing on it.

I haven't done any actual experimenting on this using the same spider(s) but I couldn't help to notice that my very small (2nd or 3rd instar) Aphonopelma sp. "Diamondback" will eat small dead crickets. They obviously can smell it as the dead crickets are carefully placed on the opposite end of where they sit at the time of feeding. Contrast to a small dead dubia roach I've given other small tarantulas (I can't remember which species though), and they never found it. The same situation though plays out time and time again with my adult Theraphosa spp. I use male dubia roaches as feeders since they run about, but large juvenile dubia roaches play dead and my spiders lose them until they move again.
That's interesting. I've always place small dubia (that I've crushed the heads) in the bottom of of my Avics enclosures at night and they have them picked up by morning. The enclosures open at the bottom and I just drop the dubia on the substrate. Which is about as far away as I can put the food from the T in the enclosure.

I do the same with pretty much all my Ts. I place a dubia on the substrate near the front of the enclosure door. They come out and pick it up usually by the next morning.

The ones in deli cups I place the food near by and they grab it on up.

I always crush the heads on the dubia. Granted they don't freeze when you crush the heads. Maybe that's why the T doesn't have problems finding them.

I've not tried one that was completely dead before it was put in. I'll have to do so and see what happens.
 

clive 82

Arachnoknight
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Ne
We've all seen it: you drop a big juicy roach right in front of your tarantula, and the roach plays dead, acting like nothing more than a rock. The tarantula is unable to realize that food is there, so it doesn't attack. You have to nudge the roach to get it to move again.
Wait, what?
Any knowledge about tarantulas indicates that they should never be fooled by this trick. Tarantulas sense their environment with their hairs all over their legs. They feel the vibrations going through the ground and in the air, and they can tell where something is and how big it is. So when the roach lands on the ground, they KNOW something is there. Sometimes, the tarantula will actually turn around and touch the roach, and they still don't attack. Even if they think it's just a stick or a rock, can't they at least poke at it to see if it moves? And furthermore, can't they smell the roach? Don't they taste with their feet? How do they not realize it's food when every single sense is telling them it is?
We've all seen it: you drop a big juicy roach right in front of your tarantula, and the roach plays dead, acting like nothing more than a rock. The tarantula is unable to realize that food is there, so it doesn't attack. You have to nudge the roach to get it to move again.
Wait, what?
Any knowledge about tarantulas indicates that they should never be fooled by this trick. Tarantulas sense their environment with their hairs all over their legs. They feel the vibrations going through the ground and in the air, and they can tell where something is and how big it is. So when the roach lands on the ground, they KNOW something is there. Sometimes, the tarantula will actually turn around and touch the roach, and they still don't attack. Even if they think it's just a stick or a rock, can't they at least poke at it to see if it moves? And furthermore, can't they smell the roach? Don't they taste with their feet? How do they not realize it's food when every single sense is telling them it is?
Never heard of a T smelling with its feet?
I think they need that movement from the prey as almost reassurance that its ok to eat. But then that doesn't explain pre killed prey?
 

AphonopelmaTX

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That's interesting. I've always place small dubia (that I've crushed the heads) in the bottom of of my Avics enclosures at night and they have them picked up by morning. The enclosures open at the bottom and I just drop the dubia on the substrate. Which is about as far away as I can put the food from the T in the enclosure.

I do the same with pretty much all my Ts. I place a dubia on the substrate near the front of the enclosure door. They come out and pick it up usually by the next morning.

The ones in deli cups I place the food near by and they grab it on up.

I always crush the heads on the dubia. Granted they don't freeze when you crush the heads. Maybe that's why the T doesn't have problems finding them.

I've not tried one that was completely dead before it was put in. I'll have to do so and see what happens.
I didn't even think of it until this post, but the method in killing probably makes all the difference. When I have fed dead dubia, it was by freezing then thawing and when I fed dead small crickets, it's been by crushing with tweezers. Freezing and thawing keeps all of the roach's body fluids contained within their hard shell which tarantulas don't detect as food using their olfactory senses. Crushing, maybe even just the head, of a dubia roach probably releases enough of a scent for a tarantula to detect it. This is all in theory of course.
 

Moakmeister

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I didn't even think of it until this post, but the method in killing probably makes all the difference. When I have fed dead dubia, it was by freezing then thawing and when I fed dead small crickets, it's been by crushing with tweezers. Freezing and thawing keeps all of the roach's body fluids contained within their hard shell which tarantulas don't detect as food using their olfactory senses. Crushing, maybe even just the head, of a dubia roach probably releases enough of a scent for a tarantula to detect it. This is all in theory of course.
You should try crushing the head next time you feed a big T
 

chanda

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Will not do it. I actually like my dubia roaches and find them to be cute. It's hard enough throwing them in with big hungry spiders. :(
Better spiders than mantises. At least the spiders will usually kill their roaches pretty quickly - and I've even had a few tarantulas and scorpions who kept dubias as "pets." I don't just mean the "one that got away" that burrows to the bottom of the substrate and stays hidden for months - I've actually found the occasional dubia hanging out inside the hide or underneath the bark, right next to the scorp or t. Mantises, on the other hand, don't really care if the roach is dead or not. They just pick an end and start eating, wiggles and all.
 

Python

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Maybe the use the movement to judge where to strike. I would imagine that they have adapted over the eons to be more careful withcertain types of prey items in order to avoid injury. By judging which direction a prey item is moving they can avoid a face to face confrontation with something that can bite back. Just my 2 cents
 

Trenor

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I didn't even think of it until this post, but the method in killing probably makes all the difference. When I have fed dead dubia, it was by freezing then thawing and when I fed dead small crickets, it's been by crushing with tweezers. Freezing and thawing keeps all of the roach's body fluids contained within their hard shell which tarantulas don't detect as food using their olfactory senses. Crushing, maybe even just the head, of a dubia roach probably releases enough of a scent for a tarantula to detect it. This is all in theory of course.
I've only ever frozen fruit flies when I was feeding really small Ts. I've not tried it with dubias though. I'll have to try it and see how mine react.

I think you maybe be right about them releasing a danger/in distress scent when you crush their heads that most likely isn't there when they are frozen/thawed.
 

Moakmeister

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Maybe the use the movement to judge where to strike. I would imagine that they have adapted over the eons to be more careful withcertain types of prey items in order to avoid injury. By judging which direction a prey item is moving they can avoid a face to face confrontation with something that can bite back. Just my 2 cents
Hey, that makes sense.
 

Trenor

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Will not do it. I actually like my dubia roaches and find them to be cute. It's hard enough throwing them in with big hungry spiders. :(
Yeah, I like watching the Dubias too. Since I bought them to feed my bearded dragon they still seem like food to me. If I didn't feed them off I'd be over run with them. I am almost that way anyway. :D
 

EulersK

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This is something that is a stark difference with true spiders. Of all the true spiders I've kept, this whole playing dead trick never works. If the spider felt movement, they know that the food is still around somewhere even if it's not moving. They'll wander until they stumble upon it and proceed to take the prey down.

Something to be said for the higher functioning of true spiders, I believe.
 

Moakmeister

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This is something that is a stark difference with true spiders. Of all the true spiders I've kept, this whole playing dead trick never works. If the spider felt movement, they know that the food is still around somewhere even if it's not moving. They'll wander until they stumble upon it and proceed to take the prey down.

Something to be said for the higher functioning of true spiders, I believe.
Maybe tarantulas are just stupid
 

viper69

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We've all seen it: you drop a big juicy roach right in front of your tarantula, and the roach plays dead, acting like nothing more than a rock. The tarantula is unable to realize that food is there, so it doesn't attack. You have to nudge the roach to get it to move again.
Wait, what?
Any knowledge about tarantulas indicates that they should never be fooled by this trick. Tarantulas sense their environment with their hairs all over their legs. They feel the vibrations going through the ground and in the air, and they can tell where something is and how big it is. So when the roach lands on the ground, they KNOW something is there. Sometimes, the tarantula will actually turn around and touch the roach, and they still don't attack. Even if they think it's just a stick or a rock, can't they at least poke at it to see if it moves? And furthermore, can't they smell the roach? Don't they taste with their feet? How do they not realize it's food when every single sense is telling them it is?
No predator is a 100% efficient predator, there is no balance in that, nature always seeks balance in some manner.

I've observed the same, with a T resting its foot on a roach or cricket for days or hours. At times stimulated by its movement only to stop once the prey stops moving. Later on they may eat or not. I cannot explain why they ate later as opposed to earlier, who knows!

I'm almost 100% positive they can discriminate size of prey to some degree without touching. I've noticed numerous tarantulas back off of prey after initial interest, only to them jump on the next cricket I placed in that was smaller. So taking different cues from their environment is all part of their neural process to attack/run etc.

They have the capability to smell roaches according to this paper http://onlinelibrary.wiley.com/doi/10.1111/jzo.12388/full

Check that out @AphonopelmaTX a bit of science for us. Study is slightly flawed however.

Humans realize there is food in front of them and don't eat it, why "can't" Ts? ;) They aren't THAT simple in my opinion.

A lot of animals aren't as simple as people think or portray them to be actually.
 
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Moakmeister

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No predator is a 100% efficient predator, there is no balance in that, nature always seeks balance in some manner.

I've observed the same, with a T resting its foot on a roach or cricket for days or hours. At times stimulated by its movement only to stop once the prey stops moving. Later on they may eat or not. I cannot explain why they ate later as opposed to earlier, who knows!

I'm almost 100% positive they can discriminate size of prey to some degree without touching. I've noticed numerous tarantulas back off of prey after initial interest, only to them jump on the next cricket I placed in that was smaller. So taking different cues from their environment is all part of their neural process to attack/run etc.

They have the capability to smell roaches according to this paper http://onlinelibrary.wiley.com/doi/10.1111/jzo.12388/full

Check that out @AphonopelmaTX a bit of science for us. Study is slightly flawed however.

Humans realize there is food in front of them and don't eat it, why "can't" Ts? ;) They aren't THAT simple in my opinion.

A lot of animals aren't as simple as people think or portray them to be actually.
It's not that they "decide" not to eat it, because when the roach moves, they grab it. It would be like if, say, you were brought into a dark room, and then the lights came on for a tenth of a second, and you're able to see out of the corner of your eye, something that looks like a burger. You can't be sure that's what it is, because the room went dark too fast. BUT, you can smell the burger, and when you walk closer and put your hands out, you can feel the bread, and the warmth radiating from it.
You then say "nope, that's not a burger. I can't see it, so it's not there."
When a tarantula's senses tell it that food is served, it should be enough to just pounce. But it waits for the thing to move first.
 

bryverine

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It's not that they "decide" not to eat it, because when the roach moves, they grab it. It would be like if, say, you were brought into a dark room, and then the lights came on for a tenth of a second, and you're able to see out of the corner of your eye, something that looks like a burger. You can't be sure that's what it is, because the room went dark too fast. BUT, you can smell the burger, and when you walk closer and put your hands out, you can feel the bread, and the warmth radiating from it.
You then say "nope, that's not a burger. I can't see it, so it's not there."
When a tarantula's senses tell it that food is served, it should be enough to just pounce. But it waits for the thing to move first.
My picky (normal?) B. smithi often crawls after MOVING dubia with a foot on it while it's crawling! I'm not talking a flash of light on the hamburger here, that light is on solid.

She just enjoys playing with dubia I think.
 
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