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Twerking is so 50 million years ago.
In fact,
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, it’s probably much older than that. Today, the provocative,
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, butt-shaking dance move is enough of a social phenomenon to merit a word in the dictionary (with twerking defined about as tastefully as possible here by actor Morgan Freeman),
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, but animals have been shaking their hindquarters for ages, for a variety of purposes (more on that below).
Black widow spiders are the latest documented twerkers. In their case,
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, it’s the males that shake their rears. Black widow females are aggressive predators and will immediately kill any prey detected in their webs. This presents a problem for males approaching a female to mate; in this case a literal misstep means becoming the female’s dinner. ?
To figure out how the males avoid being eaten (at least before mating),
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, researchers at Simon Fraser University in Canada measured vibrations created by males and by prey in webs of western black widows (Latrodectus hesperus). They compared the vibrations,
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, and the females’ responses, to those of the hobo spider (Tegenaria agrestis),
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, a species in which females rarely attack courting males. To capture the details of small vibrations, they used a fun tool called a laser Doppler vibrometer, which measures small changes in a laser beam aimed at a surface.
Sure enough, black widow males appeared to have a death-avoidance strategy. They produced vibrations different from thrashing prey by means of

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