~6e-4 (2e-4 to 10e-4) N/m
||Turtle Trachemys scripta elegans
||Crawford AC, Fettiplace R. The mechanical properties of ciliary bundles of turtle cochlear hair cells. J Physiol. 1985 Jul364: 359-79. p.359 heading '3' & p.365 top paragraphPubMed ID4032304
||"The object of the work to be described is a quantitative analysis of the mechanical properties of the hair bundles. The approach has been to measure the bending of a single bundle in the turtle cochlea by attaching it to a flexible glass fibre, and monitoring the fibre's motion through its shadowing of a light beam falling on a photodiode array."
||"For deflexions of 1-100 nm towards the kinocilium [="a special type of cilium on the apex of hair cells located in the sensory epithelium of the vertebrate inner ear.", wiki], the stiffness of the ciliary bundles was estimated as about 6x10^-4N/m, with the fibre attached to the top of the bundle...Force measurements are plotted in Fig. 3 for bundle deflexions of 2-80 nm, largely
encompassing the operating range of the hair cell. Within this range, the force was proportional to steady displacement, implying that the bundle mounting behaved like a simple spring with a stiffness of 0.62pN/nm (6.2x10^-4N/m). Measurements on other cells, all made during simultaneous intracellular recording of the receptor potential, fell between 0.2 and 1.0 pN/nm (mean±S.D. = 0.59±0.25pN/nm
n = 15)."