when I have time and opportunity I try to collect old weather instruments with a preference for analogue gauges (before digital) including hygrometers reading %humidity.My humidity monitor is displaying extreme levels. ie my hair has a constant halo of stupid looking frizz...I look like a crazy lady.
my old hygrometers that have animal hair as the sensing material are now notoriously unreliable because the hair has had too many dry hot episodes and with such weathering are brittle.
But anyways reason I say this is hair does respond to humidity
edit: wiki says “ in the year 1783, Swiss physicist and Geologist Horace Bénédict de Saussureinvented the first hygrometer using human hair to measure humidity.”