Mathematicians are fond of prime numbers. Infinitely numerous yet utterly unique, they play an integral role in number theory and a baffling one in such longstanding mysteries as Goldbach’s conjecture. Nature is partial to primes, as well, as demonstrated by the dramatic 13- and 17-year life cycles of periodic cicadas.

In this, the latest episode of It’s Okay to be Smart, Joe Hanson explores the ecological context in which cicadas have evolved; how their relationship to other animals, and other cicada broods, has led to their unusual lifecycle; and why the two broods emerging this year in the central United States wont sing simultaneously again until 2236.

For more on periodical cicadas, Hanson recommends visiting


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