///oo/\ Tarantula!

///oo/\ Tarantula!

▶ All arthropods (insects, spiders and crabs) have a hard exoskeleton, which they must shed at intervals, to catch up on their growth. Known as ecdysis (from the Greek ekduo to strip off), the process is carefully coordinated, risky in the wild, and fraught with difficulties.

▶ For several days or even weeks before the molt, a tarantula will appear moody and sluggish, refusing to eat. It spins a cradle, called molting web (seen to the left of the gif), and lays on its back. Its heart rate increases dramatically and hemolymph (“blood”) is pumped into the upper body (cephalothorax) so it nearly doubles in size. The pressure cracks the carapace along the sides and front. Wave like muscle contractions in the abdomen push the old exoskeleton, lifting it off like the lid of a can. Now comes the tricky part: the spider must work its legs out of the old shell, with forward facing hairs and bristles keeping it from slipping back inside. 

One well-placed kick, and the ordeal is over – here, have a cigar! 

♺▶ Fun Facts (aka everything you wanted to know about molting but were afraid to ask):

● Before the molt, the spider secretes a digesting fluid that loosens and eats away at the old cuticle (yum!).

● While spiderlings molt several times a year, mature females, who can live up to 40 years molt every other year. Unfortunately, many males do not survive their last adult molt, because their male sex organs get stuck in the exoskeleton (sorry, guys!). 

● The molt lasts from ~20 minutes, in babies, to several days in the adult (ladies, you sympathize, right?). 

● During a molt, spiders also shed their fangs, chelicerae (which they use for grasping), their throats and stomach lining, female genital organs (omg!), and the lining of their “book lungs”. 

● A spider that has lost a leg can regenerate one during a molt.  

Credit: This has been a fun Google+   #collaboration  with the lovely Carmelyne Thompson  for   #ScienceEveryday . Carmelyne gif-ed the ecdysis time-lapse for this post, after we discussed another cool spider molt gif on her post (http://goo.gl/fVo5fp). If you don’t have Carmelyne in your circles for more science fun, you should! 

More reading: http://goo.gl/U6w0cV

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144 Responses to ///oo/\ Tarantula!

  1. Jesse H says:

    That is so wild. Amazing too

  2. Rajini Rao says:

    Creepy and cool 🙂

  3. Armida Evony says:

    wow!! that is absolutely fascinating!

  4. Panah Rad says:

    I think it’s cool but more-than-4 legged creatures better stay away from me. 😀

  5. Rajini Rao says:

    This one has sixteen at one point!! :O

  6. Amber Peall says:

    Very informative and interesting.

  7. Amber Peall says:

    Very informative and interesting.

  8. Jim Carver says:

    Hey! How you been? I’ve been cold followed by some warmth.

    You know the one thing I remember about tarantulas was out in west Texas and I was about 2 1/2 or 3 years old and I looked over and there was one right next to me! Jeez, almost as tall as I was sitting.

    Well, I freaked out and went running to the front screaming, “There’s a giant spider over there!!!

    My brother looked at me and calmly said, “No, it’s not a spider, it’s a tarantula.”

    I said, “I don’t care, but it’s huge!”

    When we got over there the ‘spider’ was gone…and nobody believes a kid anyway. 🙂

  9. Rajini Rao says:

    I don’t understand why they are so popular as pets! 

  10. I love you six legged, two eyed ASCII tarantula! Creepy!

  11. Panah Rad says:

    I just have a problem coming to terms when things that have more than 4 legs. It’s like having 3 heads to me 😀 But fascinating creatures.

  12. Rajini Rao says:

    Not even jumping spiders? How about the peacock spider? It’s so cute, Panah Rad ! 🙂

  13. Creepy things are cool!

    Fact number 2 gave me a laugh, specially the “sorry, guys”.

    Thanks for the share, Rajini!

  14. Rajini Rao says:

    Why ASCII, Víktor Bautista i Roca ? And it’s EIGHT legs! 

  15. Amber Peall says:

    I once had a spider with twelve legs living in my garage…

  16. Rajini Rao Here’s me about to go to bed too 8-/

  17. Rajini Rao says:

    Would you say that was a mutant then, Amber Petchey ? I think the two chelicerae are in addition to the 8 legs. But that still makes only 10. 

  18. Panah Rad says:

    Rajini Rao they are cute. I like these creatures. Spiders don’t bother me. It’s scorpions that I have a bad memory of 🙂

  19. Rajini Rao says:

    Sweet dreams, Paul C Bosley hehe.

    Susana M. , I did feel sympathy for the lady spiders having to go through weeks long molting every other year! Reminded me of my dismal track record at childbirth ..but then, I stopped at two 🙂

  20. Rajini Rao I’m talking about this one: ///oo/\

  21. Jim Carver says:

    Panah Rad They hurt really bad. I’ve been stung three times. Once on the little toe.

  22. Rajini Rao says:

    I think spiders are cute too, Panah Rad . I draw the line at roaches. Ugh. 

  23. Rajini Rao says:

    Ohh, yes of course Víktor Bautista i Roca ! It also looks like it is rocking on! 🙂

  24. The number of times I thought a tarantula died only to find out it was her molt..

  25. Rajini Rao says:

    Ah, so you have actually seen this, Carissa Braun ? I read that the spider should not be fed for a few days following because it is so vulnerable, even to a live cricket. 

  26. jake hensley says:

    Ultimate out-of-body experience.

  27. Rajini Rao says:

    I could probably pull out some mystic quote relating to reincarnation, to fit 🙂

  28. Unfortunately always catch them at the end or far after, Rajini Rao, but yes. They’ll make a nice webbing around themselves to help remove the molt. When you see a lot of webbing, usually it’s best to leave them be; vulnerable to everything including a cricket!

  29. Faye Wilson says:

    Wow makes my flesh crawl yuck

  30. Rajini Rao says:

    Ralf Haring , indeed this one arose from a discussion of that shared gif. We couldn’t quite figure out how the spider wriggled out and then we found a time lapse of this tarantula molt that made more sense. I was asked about the biology behind the molting on Carmelyne’s share of the other gif, and that led to this post 🙂

  31. The best part is that you can take the shed exoskeleton and strategically place it in your home for when you are expecting company.  Let the hilarity ensue!

  32. Rajini Rao says:

    I like the way you think, Shannan Muskopf 😉

  33. That is so, so creepy/cool, Rajini Rao. Fascinating. This last summer we were in Maine and eating lots of lobster. I wonder how much of the below molting process is similar to the tarantula:

    They will increase their size by about 20% at every molt. By the time a lobster is of legal size, it will have molted about 20-25 times, averaging 4-5 molts a year. After a molt the animal is vulnerable because the new shell is very soft. It will hide among the rocks on the bottom for 6-8 weeks until its shell hardens enough to offer some protection.


  34. Rajini Rao says:

    That is extraordinary information, Gideon Rosenblatt . It really does sound like an ordeal! 25 molts/year with a couple of months of vulnerability each time. It’s amazing this process survived evolutionary selection. 

  35. nothing is destroyed  /transfered and used /process of fashion dress animal its seem tobe coco channel or gucci or yve st laurent…….the way its!

  36. Rajini Rao says:

    Very cool, Gnotic Pasta . I had not heard of a tarantula migration. I’d have to find a handy rock that was out of their path, though 🙂

  37. Jim Philips says:

    I hate it when that happens to me!

  38. Rajini Rao says:

    Jim Philips , a face lift? 😀

  39. Rajini Rao says:

    Thanks, Gnotic Pasta . The link also explains the other reason males die young. 

  40. Rajini Rao says:

    Like the RoboRoach, Mark Bruce ?


  41. Rajini Rao sitting well on the other side of the Witching Hour this post is just brilliant on so many different levels. 🙂 

  42. Rajini Rao says:

    Hope you are not arachnophobic, David Amerland ! That was one concern I had posting this. 

  43. Rajini Rao only as a kid growing up in Australia where there was a danger of Redbacks. Totally made smile as it brought back memories. 🙂 

  44. Rajini Rao says:

    Apparently, an antivenom has been available since 1956 and there have been no deaths from the bite of a redback spider since. Whew! 

  45. Rajini Rao do you know I had no idea of that in 1975? No internetz (and no one told no one nothing) 😀 

  46. Rajini Rao says:

    Pssst. Don’t let on that we were around in the days before _ 😀

  47. Has anyone watched Arachnophobia? 🙂

  48. Rajini Rao says:

    Do you recommend it, fan tai ?

  49. Heh, I watched it as a kid when it came out. Don’t really remember the plot too well, other than the giant spider in the barn… B movie, but probably fun with a few friends or if you are into spiders or like to scientifically critique it… 😛

  50. Rajini Rao says:

    I took my lab to watch Contagion and we made so many criticisms while watching that we nearly got thrown out of the theater 😛

  51. Rajini Rao lol – I can imagine 🙂 

  52. K M Idamari says:

    Regenerate a lost limb!?

    Is it a perfect regeneration or is it as messed up as in crabs?

  53. Rajini Rao wow.  Rottentomatoes gives it a 91%.  That makes it a must see 🙂


  54. Nature is so beautiful, isn’t it guys (^_^)

  55. Rajini Rao what was even better was they interviewed guy who runs the company who produced contagion, I think on Colbert Report.  He said the tea party idiots were screaming about how they wanted to kill the CDC.

    Then contagion came out.  And they went and watched it.

    And nothing more was said about killing the CDC…

    Now THAT is impressive! 🙂

  56. E.E. Giorgi says:

    wow, this is creepy and fascinating at the same time …

  57. It could be screaming too while kicking. Who knows?!

  58. I will blame you for my nightmares. 😛

  59. Rajini Rao says:

    Oh noes, Marisa Feathers 🙂

  60. Scott Ormond says:

    Rusty Van Horn might be interested in these facts.

  61. Aasim Wani says:

    u r a science lover and i love u for that

  62. Muted and uncircled. The whole bloody lot of you.

  63. Spiders give me the creeps. This post is seriously well put together though. Interesting facts! Thank you.

  64. Shit once a tarantula was on my hand and I didn’t know it was a tarantula until. I thought it was just a spider but its now I got to know its poisonous. shit!

  65. Bill Collins says:

    Suddenly I understand the phrase ‘terpsichorean echydiast’, which reoccurred in some second-rate books that I read as a teen.

    That said it also explains some odd things found in the basement, etc. 🙂 I had not realized that spiders could live up to 40 years. That’s amazing. I will have to consider putting more of them out of doors instead of squishing them when my family screams.

  66. Marta Rauch says:

    Fascinating. Thank you Rajini Rao 

    By the way, I’ve come across tarantula migrations in California at certain times of the year. That is an amazing sight.

  67. The question I have is, are each of the new legs inside one of the previous ones?  Or are they bound up separately for the push outward, or… some third alternative I can’t fathom?

  68. Rajini Rao You are so cool – now I understand Carmelyne Thompson ‘s post. An amazing process.

  69. nizar M H says:

    [?]oohh is dingers somthig. look niice

  70. great information…..

  71. Adit Morey says:

    The post was really very informative and fascinating. Nature really is a home to very fascinating and intriguing creatures.

  72. Amber Peall says:

    Decidedly, Rajini Rao . These were full on, additional four legs. It was an attic spider.

  73. Deeksha Tare says:

    Whoa! Gives me goosebumps!

    Not a big arachnid fan.

    EDIT: Do the genitals grow back then Rajini Rao ?

  74. Before watching the gif I was like “oooh ooh I want one!!” And afterwards I was like … “I knew it. They’re out to get me.”

  75. Rajini Rao says:

    Greg S. , each new leg molts inside the old one. The spider has to wriggle out of all eight legs, plus the fang bearing chelicerae. I read that they prop themselves up on pairs of legs as they wriggle out of others.

  76. Rajini Rao says:

    Marta Rauch , thank you. I learned about tarantula migrations from the comments in this post. Another risky endeavor, all for the chance to mate! 

  77. Mary T says:

    Very cool post Rajini Rao ~ I don’t mind spiders and will always take one outside if it  gets trapped in the house–but I didn’t know about the molting and shedding.

  78. Rajini Rao Super interesting!  I wonder how they work the regrowing of lost legs during molts…

  79. Rajini Rao says:

    It’s curious how some animals can regenerate body parts and other cannot…we have much to learn, Greg S. 🙂 

    Mara Rose , I don’t mind spiders either! Also since they can be long lived, it makes more sense to just move them to another location. 

  80. Stuti S A I says:

    This looks so intriguing!

    Spring is in the air!

  81. Rajini Rao says:

    K M Idamari sorry for the late response to your question, but I did not know that crab leg regeneration could be defective. When I looked it up, I was somewhat dismayed that crabs are routinely declawed for harvesting, and thrown back in the water. This is legit in many countries. I can see why this is done since the claw can be up to 50% of the crab’s body weight and is the edible part anyway. Most of the time, the claws do grow back but a quarter of the crabs die of trauma. 


  82. Angela Mia says:

    This was a very interesting, informative, and (bonus!) entertaining read. I really like your writing style.

    I had no idea tarantulas could live that long!

  83. Rajini Rao says:

    Thank you, Angela Mia . We share a love of writing 🙂

  84. You know how a shoe that is too small feels? Being free to expand has got to feel good!

  85. that’s cool but freaky. I hate spiders. Next time please post something on butterflies !!!

  86. Rajini Rao says:

    My apologies, Swagoto Ghosh . I was indeed concerned that this may set off  arachnophobic stress in some people. Will definitely post something prettier next time 🙂

  87. Rajini Rao

    no, please don’t apologise. Its alright, its cool.

  88. Shinae Choi Robinson Not icky at all!  If it helps, think of it as a land crab.

    mmm… yummy crabs… 😛

  89. Rajini Rao says:

    Excellent links, fan tai , thanks! 🙂

    Also, on a reshare, Gary Ray R pointed to research showing that “Controlled induction of molting could provide an abundant and predictable supply of soft-shelled crabs, a benefit to the soft crab industry and to consumers of seafood”.  Together with the comment on harvesting only crab legs and allowing them to regrow in molts, makes all this very relevant to you crab-eating folks 🙂

  90. Rajini Rao says:

    Thank you for the New Year wishes, Shinae Choi Robinson . Looking forward to more adventures in cooking and watching the Robinson family blossom.

  91. Rajini Rao

    why aren’t u answering me?

  92. Gary Ray R says:

    Thanks Rajini Rao, I’m one of those that really likes soft shell crab.  Years ago I lived beside the Susquehanna River and when the soft shell crab season came it was a gourmet delight.  Now one can get it year round because of this discovery. 

  93. Rajini Rao says:

    What is your question, Swagoto Ghosh ?

  94. Rajini Rao says:

    Gary Ray R , adding your comment to the list of things I learned from this post 🙂

    Actually, I hadn’t considered that soft shelled crabs were just regular crabs right after molting. 

  95. Best soft shelled crab I had was a soft shelled crab sandwich in Atlanta… So yummy

  96. J.A. Morgan says:

    That is definitely a nope….

  97. Gary Ray R says:

    I knew that food scientists had discovered something to make crabs molt on demand, never knew what it was.  From spiders to crabs, learned a lot today. Plus that is a terrific gif that will haunt all us arachnophobes. 

  98. Rajini Rao says:

    Oops, Gary Ray R 😛

  99. Irving X. Olivero S. =0!!! hay de esas bajo tu cama

  100. Jim Gorycki says:

    Rajini Rao okay, EBCDIC 8 – legged spider not ASCII?

  101. Rajini Rao says:

    Jim Gorycki , once again without the shorthand, please (for us biologists on this thread)! Are you referring to ///oo/\ ? 🙂

  102. Wes Mason says:

    SWEET MOTHER OF DARWIN. #NSFW (Not Safe for Wes) / #NSFPWA  (Not Safe for People with Arachnophobia)

  103. Rajini Rao

    my question was that, what makes a teenager get addicted towards something?

  104. Rajini Rao says:

    Swagoto Ghosh , that’s a rather broad and general question and I’m not the person to answer it. My research is not on addiction. There are many social and even genetic risk factors that contribute to addiction. 

  105. Rajini Rao says:

    Kay Shaw , hopefully a delicious shudder judging by the smiley? 🙂

  106. i thought that was a tarantula fight

  107. Jesse H says:

    Just wanted to wish you a happy Valentines day Rajini. Huggs.

  108. Rajini Rao says:

    Thanks and right back at You, Jesse H ❤

    Valentine’s Day poem and post is here: http://goo.gl/XoncAm

  109. Rozni Yusof says:

    Oooh, a striptease!

  110. Xandri Girl says:

    At first I didn’t understand it but now I do cool

  111. So how big did it become?

  112. coolsub 20D says:

    That is the most awesome but disgusting thing I have ever saw

  113. RICKEYDD says:

    ………..OHHHHHHHHHHH…. it sheded its skin

  114. dead pool says:

    Did the guy who made the video get hurt?

  115. What would u do with the sheared skin… I would scare my mom

  116. Rajini Rao says:

    Veronica E thanks for identification. Your daughter must have been a handful! 🙂

  117. Rajini Rao says:

    I can see why you would be proud of her! I bet she could tell us a lot more about arachnids. 

  118. sebi 3478 says:

    عبود البصراوي wtf

  119. Which we could do that, new skin ever so often would be great

  120. I showed that to a couple of friends, two felt sick, one though it was weird and the other felt sick. I’m going to try I on my parents next XD

  121. Nosotros lo llamamos mudan, o cambian de piel o mas bien botan el cascaron viejo.

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