Which Sex of Mouse Should You Ask for Directions?

Hormonal: It’s shorthand for erratic, volatile, unpredictable female behavior. It’s such a powerful sex stereotype that even lab rats could not escape its reach. For decades, behavioral neuroscience excluded female mice because they assumed estrus cycles made them too inconsistent to study. But the scientists had no evidence to back this up—and over the past decade research has shown repeatedly that it’s wrong.

Then earlier this year, psychology researcher Rebecca M. Shanksy of Northeastern University and a team of colleagues published that suggested male mice may actually behave less predictably than females under.