Periodical cicadas spend a majority of their life underground, eventually emerging as broods in synchronized emergences—the hallmark for what is colloquially called a cicada year. How often do these emergences occur in the northern U.S.?
Every 7 years
Oops! Try again.
Every 12 years
Oops! Try again.
Every 17 years
Correct! Excluding any cicadas that emerge off-schedule, this metric means that the last cicada year in the Michigan area would have been 2004. I can’t say I remember that far back; do you?