A spider with a taste for brrainssss....

January 1, 2010 8:53 PM

When I was 5 I brought a spider back from the dead. Or so I'm told. A long story inside...please tell me what REALLY happened.

As short as I can make it...but here are 3 stages to it.

Stage 1:

My sister, who is much older than I, remembers hearing in a high school science class that if a fly were to die but not have a physical injury (i.e. no flyswatter involved) and you put the fly in salt then the fly would return to life. My sister didn't really believe this story...

Stage 2:

That same sister then saw on Mr. Rogers neighborhood an episode where a fish died. Mr. Rogers tried to bring the fish back to life by putting it in salt water. It didn't work and ended with a little funeral for the fish and a discussion on death, but my sister put it in the back of her mind that perhaps there was something to this salt necromancy.

Stage 3:

Tonight my sister reminded me of a story from my youth. I was 5 years old and caught a spider. It was my newest pet and I took it the next day in a little jar for show and tell. It was passed to all the students who shook the jar...or perhaps there was not enough oxygen...but for whatever reason I came home from my half day of kindergarten all broken up because the spider had, in my 5 year old mind, fainted.

My sister, then 14, examined the spider. It was on its back, legs up. Per her non-veterinary diagnosis, the spider was dead. She saw my disappointment in losing a pet and thought it was time to put the salt to the test.

She poured a bowl of salt and we dumped the spider in it. A moment passed, and then the spider leaps out of the bowl and started speeding across the counter.

We are all freaked out, one by the loose spider, and two by the fact that it was a zombie spider. After we calmed down we captured the spider again but it "died" again the next day, and the salt did not revive it.

So...what really happened? Is there any truth to this salt-necromancy? Was the spider just passed out and we really pissed it off by dousing it in salt? Has anyone else heard of this salt resuscitation? Any clarification on this very weird incident would be appreciated.

posted by bodgy to Science & Nature (11 answers total)

spiders curl up and play dead when they are threatened or scared
posted by rebent at 9:09 PM on January 1, 2010 [5 favorites]

This appears to explain why a fly, under certain circumstances, may appear to have been revived by salt. However, your spider didn't drown, so that doesn't help.

All I can think of is that your spider may already have been on the edge of starvation when you captured it, the last day in the jar without food may have weakened it enough to look dead, but the salt irritated a nearly dead spider enough that it moved around again for a few hours before it finally died. And (on preview) as rebent says, many spiders do play dead when threatened.

Or maybe it was just really, really horny, and died from lack of sex.
posted by maudlin at 9:15 PM on January 1, 2010 [1 favorite]

rebent is correct. Also depending on the species, they will sit completely still and curled up for an hour or more, before jumping up and running away terrifying you.

I photograph spiders for a hobby. I collect them in old prescription bottles. Some are lively as all get out, and some just roll over and play dead. Once they are on my paper to photograph, I generally know which is which, but a few have surprised me.

The Common Barn Spider will sit in this exact position for an hour or more. And at the very least opportune moment will run right up your arm. Trust me.
posted by sanka at 9:41 PM on January 1, 2010 [13 favorites]

Like rebent says, plus that the salt likely threatens the beast more than all the staring humans, so it runs away. Spiders begin to run like mad when they feel really substantially threatened while doing the "dead" thing. I once found a very tiny one in my bed and wanted to rescue it in my glass, not realizing that there was the tiniest droplet of whisky still clinging to the bottom. That little spider leaped out of the glass, ran across the pillow and died, poor thing. A very shocking event.
posted by Namlit at 1:35 AM on January 2, 2010

I have twice rescued tiny spiders after they inadvertently spent some time in the bath with me. Both times, I was absolutely sure they were goners--not only on their backs and unmoving for a LONG while, but also bedraggled and appearing mangled, little legs askew and stuck to the sink with water. Both times, after an hour or more, they disappeared after finally drying out enough, I suppose. Seems like they are a lot heartier than they appear.
posted by thebrokedown at 3:04 AM on January 2, 2010

You seem to have your answers about spiders, but salt water is a common treatment for freshwater fish because it relieves stress in some species and because many parasites can't handle the salt.
posted by mmoncur at 3:45 AM on January 2, 2010

If you put most insects in a low-oxygen environment, they'll stop moving and look like they're dead. It's how geneticists study fruit flies under the microscope - just put some food on a stage with carbon dioxide flowing over it, then wait for the fly to land there and pass out. When you turn the gas off and the flies are surrounded by normal air again, they wake up within seconds, hale and hearty.

You can also stop them by "freezing" them with a blast of cold air - not enough to make their bodies reach 0 degrees C, but enough that they get slower and slower, then stop completely. Then wait for them to warm up again and, voom*, they're off. This is probably what luriete saw, and is used by some magicians to convince people that they're resurrecting dead flies, when it's just the warmth of their hands waking a chilled fly up.

While spiders aren't insects, their biology is similar enough that I wouldn't be surprised if spiders could be knocked out and revived in the same way. So it seems possible that the spider ran out of oxygen in there, then woke up just after you tipped it out of the jar. Perhaps the second day it was just in there too long and ran out of oxygen completely, or it starved as maudlin suggested.

I've no idea how much oxygen a scared spider would get through in a day, but it's probably not much. I'm guessing that for this to happen your jar would have to be completely airtight and quite small. Curling up in fear then running away from the nasty salt does seem more likely.

*"Voom!? This fly couldn't voom if you put five thousand volts up it!!"⁄⟨python⟩
posted by metaBugs at 4:05 AM on January 2, 2010

Playing dead is common in spiders. It's called thanatosis.
posted by dhruva at 7:59 AM on January 2, 2010

Here's a blog post describing the Mister Rogers episode, "Death of a Goldfish," which does include him trying to revive it with salt water.
posted by The corpse in the library at 8:07 AM on January 2, 2010

I don't know about the sort of spiders you typically see in North America, but when a tarantula molts (sheds its exoskeleton), it first flips on its back and lies very still. Often their owners worry that they are dead the first time it happens. The whole process can take several hours. They are extremely vulnerable while this is happening and they are still vulnerable for days/weeks after (until the new exoskeleton has hardened and the new fangs are strong enough to kill food and bite predators).

It's possible your spider was just about to molt, and when disturbed it flipped back over and tried to seek a safer place. There are a few time-lapse videos of the process on youtube (like this one) if you want to see it happening in the space of a few minutes.

When one dies, it doesn't usually flip onto it's back--it stays upright with its legs curled tightly underneath.
posted by K.P. at 9:32 AM on January 2, 2010

Salt water (carefully controlled) is a legitimate cure for a fish with dropsy (it doesn't always work, but dropsy is fatal anyway, so it's worth a try).
posted by pseudostrabismus at 12:52 PM on January 2, 2010