Figure 2. Maximal whisker deflection.

Top: sketch of a passive whisker (blue) deflected by contact with an object (green). The deflection angle θ is the angle between the direction of the whisker base and the direction of the object. Bottom: maximum deflection angle as a function of normalized object distance x/L for two cat whiskers, two rat whiskers, and two artificial whiskers cut from steel wire or plastic fishing line. Solid line is the prediction of elastic beam theory for an untapered whisker under large deflections [47], assuming a frictionless contact between whisker and object. Error bars show standard errors (n = 4), and in some cases are smaller than the symbols.