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]

18 thoughts on “The scariest animal that will never hurt you

  1. 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.

  2. 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.

  3. 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.

  4. 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.

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  13. 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.

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