Spider-Tailed Viper

odd-creatures-spider-tailed-viper

Odd Creatures is a recurring column about the world’s weirdest species written by award-winning science writer and author Bec Crew, and illustrated by the super-talented Aiyana Udesen

 

Hey, nightmares are pretty bad, but how about two nightmares combined into one horrible amalgamation of terrifying animals whose entire existence revolves around hunting and killing? Meet the spider-tailed viper, a strange reptile found in the Arabian Desert.

In 1968, a group of scientists travelled to Iran to collect a bunch of native species for the Field Museum of Natural History in Chicago. Among the reptiles they collected was what looked like a strange mutated snake. All bottled up and preserved in alcohol, the specimen, named FMNH 170292, appeared to have a large camel spider attached to the end of its tail. Further examination revealed it to be a peculiar growth that looked exactly like a spider.

It was the only snake like this that had ever been found. It was impossible to say whether the mutation was genetic, or maybe it was a tumor, or perhaps a reaction to some sort of parasite.

Four decades came and went, until 2003, when zoologist Hamid Bostanchi collected a second snake with the exact same tail ornamentation. Having examined it and the museum specimen, Bostanchi declared the snake a new species and named it Pseudocerastes urarachnoides. ‘Pseudocerastes’ means ‘false horns’, these vipers have horn-like structures above their eyes that are formed by a build-up of small scales, and ‘urarachnoides’ means literally ‘a tail similar to a spider’. Rivaled only by the rattles employed by the venomous pit vipers of North America, the spider-tailed viper has the most elaborate tail embellishment ever seen in a species of snake.

The spider-tailed snake is a desert species, rarely seen but found in the North Arabian Desert from Sinai and southern Israel, Jordan, Iraq, southwestern Iran, Afghanistan, Pakistan and northern Oman. Only Bostanchi had seen one alive at this point, so there was no way of knowing what the tail was actually used for, but he suspected it worked like a fisherman’s lure to attract the birds that hunt camel spiders. Makes sense, he said, because he found the remains of a bird in the stomach of one of the specimens.

A few years later, biologist Behzad Fathinia from Razi University in Iran decided to test Bostanchi’s theory. With a group of colleagues, Fathinia caught a live snake and took it back to the lab. They put a chick in its enclosure to see what it would do. The snake moved its tail embellishment exactly like a spider. “We were able to observe and film the [tail] luring. It was very attractive and looked exactly like a spider moving rapidly,” they reported in 2009. “After approximately half an hour the chick went toward the tail and pecked the knob-like structure. The viper pulled the tail structure toward itself, struck and bit the chick in less than 0.5 seconds.”

They also put an ill-fated male sparrow in with their viper and when the viper saw it, it moved in the corner of the enclosure, formed a coil with its body and positioned its spider tail right in front of its mouth for easy striking. The team concluded that it was not only birds that were caught by the spider-tailed viper’s spider-lure, but also reptiles and even mammals such as shrews; all were the likely prey of these bizarre desert killing machines.

 

—Bec Crew / @BecCrew

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