SUMMARY The feet of the jumping spider Evarcha arcuata attach to rough substrates using tarsal claws. On smooth surfaces, however, attachment is achieved by means of a claw tuft, the scopula. All eight feet bear a tarsal scopula, which is equipped with setae, these again being covered by numerous setules. In E. arcuata , an estimated 624 000 setules, with a mean contact area of 1.7×10 5 nm 2 , are present. The spider's entire contact area thus totals 1.06×10 11 nm 2 . Adhesion to the substrate does not depend on the secretion of an adhesive fluid. Analysis via atomic force microscopy (AFM) shows that a single setule can produce an adhesive force (F a ) of 38.12 nN perpendicular to a surface. Consequently, at a total F a of 2.38×10 –2 N and a mean body mass of 15.1 mg, a safety factor (SF; F a /F m , where F m is weight) of 160 is achieved. Tenacity (τ n ; F a / A , where A is area of contact) amounts to 2.24×10 5 N m -2 .