# Tarantulas can sense rain.



## P. Novak (Oct 10, 2007)

Ok, I was watching a movie, got up and decided to check on my Ts. I walk into my room, turn on my light, and EVERY single one of my MATURE Ts are out and about.. even my most elusive Ts: _H.lividum_, _H.maculata_, _P.ornata,_ _P.formosa_, _C.huahini_, _C.bechuanicus_, _P.murinus_. etc. Not one of my Ts is in it's hide, they are all up on the glass, climbing around. I've never observed or heard of this before. 

So Ts can and do sense rain, but why? My intitial thought is it's a stimulant for breeding, since the females are pasing around the cages like mature males would. Can anyone back me up on this?

Any thoughts on this?

Oh yeah, this is the first time it's rained for awhile.


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## Ralph (Oct 10, 2007)

Just my guess....that those borrowers're afraid of being submerged or drown by  the big rain or flow......they gotta move out of their borrow and to seek for a high land to survive.that's they result of going out of nest of my suspet.but for how can they sense that.......i dunno...


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## mwh9 (Oct 10, 2007)

I would guess that they can sense the change in barometric pressure, they are not getting wet, yet something is telling them that may be about to happen.


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## problemchildx (Oct 10, 2007)

Ralph said:


> Just my guess....that those borrowers're afraid of being submerged or drown by  the big rain or flow......they gotta move out of their borrow and to seek for a high land to survive.that's they result of going out of nest of my suspet.but for how can they sense that.......i dunno...


I dunno either, but that is a very good point!

Since I got my first T it has pretty much been raining heavily every day since. (Anyone spend the fall or spring in Puget Sound area? ) I haven't noticed any behavior you are describing from my irminia or versicolor, however my new aureostriata is almost always above ground at night. And even though I have only had him/her for like 2 weeks, I can tell that I might actually love this spider like a brother. lol Like you are saying, I see her/him as far up in the small KK as he can go towards the top often sitting there for hours. 
My A. Seemanni, when he's not chillaxin in his hide/burrow, can often be seen on the corner of his KK, with front legs all the way up, and sort of leaning on the vent holes. As if he is smelling the rain perhaps? I neglected to include my tiny albopilosum, since it is a rare sight to see it above ground.


Didn't wanna make a new thread for this, so I'll throw it in there.
Another thing that struck me as "cute" was tonight he was using his back left leg as a buttscratcher! It was quite a sight, as I giggled while watching for about 15 mins. (He/she did this for well over an hour) I am positive this isn't caused by any mites or parasites, but rather just the odd behavior of the oh so frequently dubbed "Gentle nutjob" 

Have any of your Ts done this?


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## P. Novak (Oct 10, 2007)

Yea, but even the arboreals?


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## problemchildx (Oct 10, 2007)

If you are referring to the rain topic, my arboreals seem to hide (irminia) or  lull around their comfy hammock being fatties. (versi) I think I provide enough humidity for them so that they probably can't tell the difference between morning dew, or a coming storm.


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## P. Novak (Oct 10, 2007)

problemchildx said:


> If you are referring to the rain topic, my arboreals seem to hide (irminia) or  lull around their comfy hammock being fatties. (versi) I think I provide enough humidity for them so that they probably can't tell the difference between morning dew, or a coming storm.


Yea, that is what most of my arboreals do normally, but today, the first night of rain for a couple months now, they are all out and about. They weren't earlier when it wasn't raining, but they are now. So I don't know how accurate it would be to say that the Ts sense the rain and are just crawling out so they potentially won't get wet... I mean I guess it makes sense for the burrowers, but it doesn't explain why the arboreals are doing it. Oh and I don't know how many of you caught it, but only the potentially mature females/males are out. The slings have remained as they were before it raining, even the burrowers.


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## problemchildx (Oct 10, 2007)

The only real way to prove this is to have some sort of scientific experiment. 

Not sure about the variables of said study, but maybe the hypothesis something like:

Healthy sub-adult/adult Tarantula's that are living in a high barometric pressure zone can perceive the rain and will readily come out of concealment when it rains. 

Hmm? You could even test out slings of all types and juvies, OW, NW, AB, TR, pet holes, etc, etc.

Alas, most likely a very firm and stable experiment would have a high rate of failure. I haven't read or heard about this rain/Ts phenomenon, but it's not an exact science. For all we know, your T's have been planning a get together for months now behind your back! ;P 

I was never great at this type of science, I'm more structured to the experiments and surveys in Psych.


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## P. Novak (Oct 10, 2007)

Ah yeah, but this would be nearly impossible to experiment, I mean there is no way I can replicate real rain or pressure. I will just jot down a few notes here and there. I know I know, there is no way I can prove my theory or anyone elses without tests, so alas, this will remain another T mystery..


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## problemchildx (Oct 10, 2007)

Ever since the creation of smoke signals, the most creative scientists, chemists, physicists, etc have superb networking and trade journals/info or try to help each other out.

Either way, it is completely impossible. Especially for if you wanted to test the results of ALL Ts 

Even though we can't prove it, what you say is logical. I have no problem believing this too


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## P. Novak (Oct 10, 2007)

problemchildx said:


> Ever since the creation of smoke signals, the most creative scientists, chemists, physicists, etc have superb networking and trade journals/info or try to help each other out.
> 
> Either way, it is completely impossible. Especially for if you wanted to test the results of ALL Ts
> 
> Even though we can't prove it, what you say is logical. I have no problem believing this too


Haha thats reassuring.  

Maybe one day we'll be able to complete a couple of tests to throw some of these mysteries out the window, but not this day.  

I thought I'd take the opportunity to take some pictures so here's some pictures of some of the wanderers that actually remained outside for a picture instead of running to hide. The _P.formosa_'s cage was misted, since it was looking fairly dry, that is why it is wet. I also hate flash, but no sun out right now, so this will have to do.

_Ceratogyrus bechuanicus_






_Haplopelma lividum_






_Poecilotheria formosa_






_Heteroscodra maculata_


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## problemchildx (Oct 10, 2007)

Wow.. just wow.

Just the fact that your lividum is crawling on the glass/plastic with a clear kodak moment should be proof enough. 

May I add she is one of the better looking lividums I have seen lately. :clap:


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## WARPIG (Oct 10, 2007)

mwh9 said:


> I would guess that they can sense the change in barometric pressure, they are not getting wet, yet something is telling them that may be about to happen.


This would be my guess as well, many animals in nature are sensitive to barometric pressure, and T's have to be especially careful as not to drown in their homes.



PIG-


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## problemchildx (Oct 10, 2007)

Especially since a great number of Ts are native to areas with low annual rainfall. A couple rainy days a year could easily mean a complete flooding of their shelters, and when it rains, generally speaking it pours. :}


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## Talkenlate04 (Oct 10, 2007)

mwh9 said:


> I would guess that they can sense the change in barometric pressure, they are not getting wet, yet something is telling them that may be about to happen.


I agree with this statement 100%. They can't sense it is going to rain but they can sense that something is about to change. You will notice if you pay attention to the weather that when a weather front rolls through your area most Ts are more active. You will see a lot of molting, digging, webbing, if ypu have gravid mothers you will see sac production, and general activity. What exactly the direct correlation is I am not sure but barometric change seems to be something tarantulas can pick up on.


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## Corranthe (Oct 10, 2007)

talkenlate04 said:


> You will see a lot of molting, digging, webbing, if ypu have gravid mothers you will see sac production, and general activity.


Yup... waiting for it to rain here in D.C.  Just about my whole collection (11 Ts) is ready to molt.  But everybody seems to be waiting for it to rain...

Fate decided that I should pick up this hobby so that I might learn a measure of patience.  :wall:


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## UrbanJungles (Oct 10, 2007)

Lots of creatures can sense the change in barometric pressure and in many species it usually stimulates them to move around.

I have several treeboas in my collection, all housed in the same room with my T's.  Last night we had one of those cool nights with alot of lightening and thunderstorm activity soon to follow.   Every one of my snakes were awake and cruising around (not something Emerald tree boas frequently do) as well as my spiders.

They definitely know when a change is on the horizon...


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## bio teacher (Oct 10, 2007)

As a biology teacher, I think you could definitely do an experiment. Everytime it rains write down your observations. Write down your observations when it doesn't rain. If this behavior is only happening right before or during a rain, it is pretty safe to say that the T's are sensing a change in barometric pressure and are altering their behavior because of it. The first step in the scientific method is observations.


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## Talkenlate04 (Oct 10, 2007)

It's not just the rain. The front of a front can be hundreds of miles ahead of the rain. So I have personally have been tracking when molts occur in relation to barometric pressure changes and at what barometric pressure those activities are occurring at. I have a trend going but I need a few dozen more molts to confirm what I am seeing.


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## bio teacher (Oct 10, 2007)

Sounds great. Once you get enough data, it might be worth submitting to a journal. There is not alot of behavioral data on tarantulas yet.


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## whitehaze2008 (Oct 10, 2007)

*all insects*

can sense when it will rain. 
Its part of there survival. Insects would not be able to cop or live in a torrential downpour without prior notice.
They have an organ that senses the barometric pressure, and thus can predict the rain, much better than our best meteorologist.

Im also a beekeeper, and i can ALWAYS tell if its going to rain of not, because the bees will not be flying....even if the sun is totally out, and there are no bees flying in and out of the hive, yep its about to rain.

Just one more miracle of God himself.
-David


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## Talkenlate04 (Oct 10, 2007)

But they don't sense the rain coming they sense the barometric pressure change. Now that pressure change is normally associated with the rain coming in behind the front, but that does not mean they can sense rain coming, only means the are capable of detecting pressure changes.


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## whitehaze2008 (Oct 10, 2007)

*um*

There are three types of rainfall

orographic, convectional, and frontal.

*Orographic* is when the warm humid air mass runs into a mountain and is pushed upward on the mountain slope. When the elevation reaches the "zone of saturation" the moisture in the air cools and turns to rain. This is where a larger majority of mountains recieve there rains from.

*Convectional * is when the moist air heats up and rises itself to the zone of saturation as it rises to a higher elevation. This is where 90% of all rainforest recieve there rainfall.

Frontal is where a warm or cold air mass rushes in and shoves the cooler or warmer air mass upward into the zone of saturation. This is how the middle and eastern portions of the plains of America revieve alot of there rain and temperature changes from.

- all three types of rain will cause a major drop in the barometric pressure.
Also severe weather patterns can cause a drop in the barometric pressure. This may or may not be with rain though.


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## Ewok (Oct 10, 2007)

Corranthe said:


> Fate decided that I should pick up this hobby so that I might learn a measure of patience.  :wall:


hehe are you one of those people that want to pull the tarantula out of thier old exuvium before they are ready?


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## whitehaze2008 (Oct 10, 2007)

*lol*

no no lol why you ask?


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## Corranthe (Oct 10, 2007)

Ewok said:


> hehe are you one of those people that want to pull the tarantula out of thier old exuvium before they are ready?


It wouldn't be a big deal really except that I am leaving in ten days to go overseas for another ten days.  I would feel more comfortable if everyone who is going to molt did so before I leave because I have a bunch of slings who will need to be fed and watered.  As much as I trust my roommate to make sure everyone is watered every day, she a) really doesn't care about my Ts at all and b) is rather clumsy and I'm not too sure I'd feel comfortable with her feeding them anyway (esp the tiny little 2nd instars).  Ten days without food is fine, cuz it just means I'll come home to everyone being ready to eat, but with the whole pre-molt thing...  They are getting me all worked up about the timing.


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## Talkenlate04 (Oct 10, 2007)

> There are three types of rainfall


 I am aware of the different types of rainfall, but the pressure change associated with a front is almost always ahead of the rain.

That's all besides the point. My trend I have been noticing is that the molts and eggs sacs are being conducted ahead of the rain. Not during the rain.


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