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.
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.)
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.
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.
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.