The scariest animal that will never hurt you

Several species of tailless whipscorpions live in caves, like this Daemon variegatus from Mozambique. [Canon 7D, Canon 14mm, Canon MT-24EX twin light]
Of all the animals that you may encounter in a tropical rainforest, none evoke a more visceral, negative reaction in even the most ardent nature lovers than the tailless whipscorpions. They are members of the order Amblypygi, and among all arachnids they are probably the most undeserving of fear or repulsion.

The first pair of legs of whipscorions resembles insect antennae in their length and function. Their surface is covered in bristles, trichobothria, and slit organs that detect the presence of and the distance from the prey. [Canon 1Ds MkII, Canon 16-35mm + extension ring, Canon MT-24EX twin light]
To begin, they are completely harmless to us. Tailless whipscorpions do not produce venom or toxins, nor are they capable of biting, stinging, or injuring a person in any way. They do not transmit diseases and they are not pests. But they do have the misfortune of having a beautifully symmetrical, armored body that for some reason our primitive, stone-age psyche automatically associates with something bad or scary.
This really is unfortunate because these animals are fascinating. They belong to a lineage that goes back in time to at least the Carboniferous, and has remained relatively unchanged in their morphology. Only about 140 species are known, mostly from forests of warm and humid tropical areas within the tropics, and only a small handful have ventured into subtropical regions of Europe and North America (including one interesting species from Florida that is capable of staying submerged underwater for up to 8 hours.)

Heterophrynus sp. from Guyana has just sensed a cricket and is ready to pounce on it the moment the insect moves. This genus has some of the longest pedipalps among these arachnids. [Canon 5D, Canon 100mm, Canon MT-24EX twin light]
Like most arachnids these animals are predators (although some are apparently partial to rolled oats, of all things.) They are sit-and-wait hunters, using their first pair of extremely long antenniform legs to detect approaching prey, insects mostly, with an array of motion- and scent-sensitive trichobothria, bristles, and slit organs. Once the prey is detected within striking distance, the whipscorpion pounces on it and crushes it with its spiny, muscular pedipalps. The prey is then masticated with smaller chelicerae and digested externally, before the liquified meal is directed into the mouth via grooves at the very base of the pedipalps.

Two males of Costa Rican Phrynus parvulus engaged in a territorial battle. [Canon 10D, Canon 100mm, Canon MT-24EX twin light]
Whip scorpions are passionate animals, both in love and war. Their courtship ritual is surprisingly elaborate and gentle, and may involve hours of slow dancing, tender caressing, and hand-holding, before the male places an external spermatophore on the ground and slowly guides the female to pick it up. After a while she will produce a clutch of eggs and carry it on her body until the babies hatch. After their emergence the young whipscorpions, known at this stage as praenymphs, are still quite helpless, and the mother carries them on her body some more, until they are ready to fend for themselves.
Young whipscorpions occasionally aggregate into small groups but adults, males in particular, are pretty cantankerous and territorial creatures. They will not tolerate another individual of the same sex in their vicinity, resulting in intense albeit largely ritualized battles.

Female whipscorpions are devoted mothers and carry their young until these are ready to begin independent life. [Canon 1D MkII, Canon 100mm, Canon 580EX speedlight]
Nearly every place where I found whip scorpions, and they are remarkably common and abundant in most tropical areas of the globe, their presence, their very existence even, came as a surprise to the local residents. On the Caribbean island of Saba I saw them in the garden of a local couple of amateur biologists who, despite having lived there for nearly 20 years, had no idea that whipscorpions were sharing their space. In Mozambique I caused a sensation by pulling one out of a dark corner of a building occupied by the staff of a national park, and in Suriname my local guide almost peed his pants from excitement when I showed him one. This is mostly because these animals are secretive and shy, and only come out to play in the middle of the night. Even then you must be pretty careful while approaching one as it will flee the moment it detects your presence. But, if you are patient enough, you may be rewarded with a peek into the life of a truly remarkable animal.

Note: Other common common names are sometimes used for this group of arachnids, including tailless whip spiders and amplypygids. The name whipscorpions is often spelled as two words – whip scorpions – but I prefer to combine them into one to emphasize their distinction from true scorpions, members of the order Scorpiones. The same principle applies to insect names: scorpionflies, stoneflies, and butterflies are not flies, and this fact is indicated by combining the root “-fly” with the modifier into one word. Crane flies, on the other hand, are true flies.

Unlike insects and most arachnids, tailless whipscorpions continue to molt periodically even after reaching maturity. [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]
Cannibalism is not uncommon among tailless whipscorions, as demonstrated by this Phrynus sp. from the Dominican Republic. [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]
Members of the genus Charinus, like this C. pescotti from northern Queensland, have very short pedipalps. They apparently hunt by gently herding their prey towards the mouth with the antenniform first pair of legs, and only when the victim is very close, grab it with the pedipalps. [Canon 10D, Canon MP-E 65mm, Canon MT-24EX twin light]

42 Comments Add yours

  1. Michelle says:

    Thank you for this informative article and the excellent photos!

    I was searching for the name of and information about this species after seeing a video on Facebook.

    1. Paul Bruney says:

      I have never seen one of these. Im in Surprise Srizona and found one in my watervalve box at work.
      True to your research it surprised and amazed me at the same time!
      Its a very interesting looking creature and kind of spooked me because its different than all the Spiders, Scorpions and wind scorpions ive caught here.
      It is very unique to say the least.

  2. Hal says:

    Follow up – the way I found this page was a search for “costa rica scary fast bug.”

  3. Hal says:

    This was a very well written description of something that I found absolutely terrifying in Costa Rica. I had rented a small cabin, and saw one in the kitchen. It moved -so- fast, and looked -so- scary that I had some difficulty settling down and dealing with being inside. It didn’t help that there was just a single low wattage light bulb, making me even more uneasy as night came on. It certainly seemed at the time like the fastest moving critter I’d ever seen; much faster than cockroaches, for instance. I’m glad I made it through your article, and saw the varied and sophisticated aspects and morphologies, and the brooding mother. It’s amazing that I’m still a little shaken about this maybe 15 years later. Maybe l’m not so tough, after all. I can remember coming face to face with what seemed like a very large, green scorpion in a hole in the Mojave Desert when I was a little kid, and running all the way home! Thanks from western Oregon, USA.

  4. moo moorawsedrfgtttttttttt@ugbb says:


  5. juyh@ugbb says:

    i have held one

  6. Fbfb says:

    That kinda creeped me out but it gave me a lot of facts about it thank you

  7. Demara says:

    Carolyn Hughes: How sweet are you to care about its spouse! I loved your post.
    This is really neat! Does anyone know if these live in Hawaii? I live in Alaska (where the only things that can kill you, you can see coming a mile away) but am going to Hawaii in a few days with my sister. My sister is terrified of spiders…just want to know if I can *legitimately* mess with her a little bit about what she might find under her bed. (hahahaha…but no worries – I’m a ‘move it out of the house’ kind of girl…we don’t squash harmless creatures). :) Thanks!

  8. Just found a vinegar own in my house. Took it out and placed it in an area with rock and heavy shrubbery . Was that a good place? I heard that vinegar oops mate for life. Is that true? Does that mean that the spouse is in my house? Will they find each other? Thanks.

  9. I know they are incapable of any lasting damage, but doesn’t their claw hurt just a little? Like a clothespin?

  10. Leruschka says:

    Thank you for this post and photos. It took me about 3weeks to find out more about this species. The thing that I still find very strande is that you mostly get them in tropical places (if I’m correct) and I found one in my flat in South Africa. Its still very small but had the household freaked out for a while

  11. Jochen Greif says:

    I am very glad to find an expert who tells us details about an insect which I have seen a few times at darkness on my plantion in Thailand. And now I finally know it`s name! Good to know it`s not dangerous; that was my first thought.

  12. Martin Hat says:

    I have no particular interest in insects but I enjoyed this article. It was both interesting and very well written. Thanks.

  13. markjnewton says:

    Wonderful article and very informative. I shared this to educate ohers who might be tempted (like too many of our sad species) to smash the poor things on sight. Such incredible animals. Thanks for puting this together.

  14. Leilane says:

    Finally I know what this insect is! I have been finding it quite often in my kitchen sink.

  15. Sarah says:

    Loved it. Thanks so much
    learnt so many new things

  16. Reblogged this on dragonsmagicpaper and commented:
    This creepy insect wouldn’t hurt you unlike other intimidating insects that could kill you.

  17. Ruiz says:

    I’ve been seeing these in my backyard for years since i was a boy in Trinidad & Tobago, i never knew what it was until i saw a documentary that mentioned this “by the way”. I think it’s awesome.

  18. vib says:

    Beautiful pictures there, Piotr. I still do wonder what’s their defense mechanism when threatened, other than scuttling away(as you say).

  19. gudbjorg2 says:

    Nice, educating and intresting to learn about those unusual species. Thanks for that.

  20. chris y says:

    When we lived in Tanzania, one of the facts of life was that Diademas liked to burrow into piles of laundry, presumably for warmth and shelter. You sort of expected one to emerge when you shook out the clothes, but it was always a bit of a shock because they move so darned fast.

  21. Celia says:

    Fascinating details about an unusual ancient species – thank you for your post and photos!

  22. ekinodum says:

    I worked as a boxboy at a supermarket in southern California 40 years ago- one day one of these came in (barely alive) with a fruit shipment. I kept the specimen for several years without really knowing what it was (except I knew it was not a spider). Nice post.

    1. fuckoff says:


  23. Snail says:

    Fantastic post. Charinus pescotti occurs relatively close to my place in NE Qld, but they seem to be a lowland species. Must be too cold for them up here on the Tablelands. I’ve searched for Charon trebax, the other Qld species, at type locality S of Townsville, but no luck. Plenty of snakes, though.

  24. A nice selection of species from around the globe. I’ve seen them in Arizona and Ecuador but haven’t had a chance to photograph them in the wild yet. I do have photos of a Tanzanian Diadema and the Floridian Phrynus that a friend has in culture, Simply spectacular animals!

    Few groups trigger more common name arguments than this one – this one at Wikipedia being an especially humorous example.

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