Fig. 11
From: Tree frog attachment: mechanisms, challenges, and perspectives
Variation of the falling angle α⊥ with substrate roughness Ra on an inclined, dry substrate (circles from Fig. 5 in [43], Hyla microcephala; crosses from Fig. 8A in [9], Colostethus trinitatis; diamonds from Fig. 3B in [10], Rhacophorus pardalis; squares from Fig. 1B in [97], Litoria caerulea). Green areas denote the diameter range of nanopillars (left) and epidermal cells (right) reported in the main text. Dashed line: Falling angles below 90° show the lack of adhesive abilities. Most roughness values mentioned in the references are approximations and do not originate from measurements