Merino sheep are prized for their super-fine wool. In a skin area about the size of a postage stamp, these sheep will carry between 10,000 and 15,000 fibers. The fibers are less than 19.5 microns wide. By comparison, they typical human hair is 60-70 microns wide.
The wool of sixty merino sheep, tied end to end, would make a string that would reach from the earth to the moon.