How Dangerous Are tarantula Spiders?

Factual Questions
41

[QUOTE=elucidator]
The American Barking Spider (Flatuus Deadliae) is mostly harmless, and serves as putative culprit for otherwise inexplicable eructations from the Nixon.

From my reading, it appears that Austrailian wildlife falls into two broad categories: animals that will kill you, and animals that will kill you and eat you.
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I am not sure if it is because I’m Australian or just dumb that I don’t understand your barking spider - but then again Nixon is one of your ex-presidents, so I suspect I am on totally the wrong track.

Re real spiders and snakes and all our other deadly stuff - it’s pretty well a great big myth. We don’t have bears or big cats or rabid creatures! Camping in our bush is totally safe. The biggest risk in the outback is running out of water. We have plenty of deadly critters, but they dont tend to kill anyone very often other than the occassional crocodile who wants to get into the news. We are better are sensationalising than educating.

Loved the photo Boscibo. I am SOOOO jealous.

[QUOTE=TV time]
One of the most fascinating things I have seen tarantulas is when they go into attack mode. It is wonderfully scary to behold. They rise up on their back four legs and come rushing at their target (once a friend and me) waving their front four legs and making a phleming throat-clearing sound. If I hadn’t grown up with spiders as a youngster, I would have been terrified as my friend was who froze in place and whom I literally had to drag away.

Whenever I tell the story, there are people who say that spiders don’t rise up on their back legs and attack making weird noises, but fortunately enough people have come across the action that I have back up witnesses.
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They rear up to attack because their fangs point downwards. All mygalomorph spiders do. That’s the tarantulas, trapdoor spiders, what we call funnel-webs (like the Sydney funnel-web) and our mouse spiders. All other spiders (known as araneomorphs) have their fangs coming together in the front, parallel to the ground, so they don’t raise their bodies to attack.

I wish we had proper flashy looking tarantulas like you Americans do.

Lynne

42

[QUOTE=lynne-42]
They rear up to attack because their fangs point downwards. All mygalomorph spiders do. That’s the tarantulas, trapdoor spiders, what we call funnel-webs (like the Sydney funnel-web) and our mouse spiders. All other spiders (known as araneomorphs) have their fangs coming together in the front, parallel to the ground, so they don’t raise their bodies to attack.
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The running on the back legs was weird enough, but the sound really was strange. Clearly, movie makers have not heard it because if they had, they would use it.

43

[QUOTE=TV time]
The running on the back legs was weird enough, but the sound really was strange. Clearly, movie makers have not heard it because if they had, they would use it.
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I haven’t heard spiders making a sound, although I know our barking spiders (our tarantulas) do. Were they running as they made the sound?

How loud was this sound? Can you describe it? I must find out how they make it.

Lynne

44

[QUOTE=lynne-42]
I am not sure if it is because I’m Australian or just dumb that I don’t understand your barking spider - but then again Nixon is one of your ex-presidents, so I suspect I am on totally the wrong track.
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'Luci’s flourescent verbiage is sometimes equivalent to Cockney rhyming slang in its obfuscatory nature. By “Nixon” he means “asshole”; the “Barking Spider” only exists to wave away certain “noises” that might otherwise have embarassing explanations. (Note also the Latin name of the ‘spider’.)

45

[QUOTE=CC]
When I was a kiddo, I was haunted by a movie called Tarantula. Not so much because of the giant spider that was attacking the town (cliche much?) but because of what the venom was doing to the townspeople, including one of the scientists brought in to find out what was happening. Their faces got soft and sagged, and it was so creepy that I almost ran from the theater. Leo G. Carroll, maybe, was the main guy, and his face looked like it was going to melt off normally, so he was perfectly cast for this role. Maybe I’ve got details wrong, but it wasn’t the tarantulas that were so horrid, it was that side effect. ewww
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Clint Eastwood’s first movie. He’s one of the fighter pilots at the end. He included a quick scene from it in Coogan’s Bluff. (Yes, that was me that added that IMDb trivia :))

46

[QUOTE=lynne-42]
I haven’t heard spiders making a sound, although I know our barking spiders (our tarantulas) do. Were they running as they made the sound?

How loud was this sound? Can you describe it? I must find out how they make it.

Lynne
[/QUOTE]
It was indeed running (the back legs thing). The reference I made in my first post captures it, I think, best of all. The volume - It was, what, in my theater days would have been called a stage whisper. Loud enough to be heard, but undermodulated.

47

[QUOTE=TV time]
It was indeed running (the back legs thing). The reference I made in my first post captures it, I think, best of all. The volume - It was, what, in my theater days would have been called a stage whisper. Loud enough to be heard, but undermodulated.
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This is proving to be a most intersting comment. I have just spent two hours going through references and online. The sound making is called stridulation although very few of the references mention that word. Wikipedia says:

"Spider Stridulation

Most spiders are silent, but some Tarantula species are known to stridulate. When disturbed, Theraphosa blondi, the Goliath tarantula, can produce a rather loud hissing noise by rubbing together the bristles on its legs. This is said to be audible to a distance of up to 15 feet (4.5 m)."

A child’s book I have on American tarantulas, which does seem to have reasonable quality science, says the sound is made by the bristles on the chelicerae, which are the appendages which hold the fangs.

For our whistling spiders (also family Theraphosidae), the few references are in total agreement with what Robert Raven has written here .:

"Australian tarantulas differ from those in South America by having a lyra of spines and picks on the opposing faces of mouthparts (maxillae) cheliceral and this lyra gives the spiders the ability to make an audible whistle or hiss when the spider is aggravated. The hiss can easily be heard 2m away in a quiet area. That hiss or whistle is what gives our spider its other name Whistling Spider. They are sometimes also called “barking spiders” but whistling is the most accurate description of the sound. The function of the sound is unclear. It is not used during mating and when present is present in both sexes. It is used when the spider is aggravated. "

As Raven is considered a world authority on mygalomorphs, especially the Australian funnel-web (like the deadly Sydney funnel-web) and and gets his name in brackets after heaps of them because he has classified so many, his word is authority.

So if I put this all together correctly, the North American tarantulas and our whistling spiders use the chelicerae, but may be using different structures to do so, while some of the South American ones might use their feet. Not sure I have that right yet.

Foelix’s “Biology of Spiders”, which seems to be the generally accepted authority on physiology, says (p.265) that stridulation 'is generating a sound on the spider’s body by moving a “scaper” over a “file” ’ and then says there are a whole range of stridulating structures have been described structurally. The trouble with writing books is that people quote them, so anything I write of a technical nature has to be double and triple checked. Think I might have gone on a bit too much on this one - it was just that you raised such an interesting point, TV time.

Any information would be welcomed!

Lynne