Fig. 1: Remoras adhere to various soft substrates.

a, Representative measurement of lamella orientation of P. lineatus. Scale bar, 1 mm. b, Remora species exhibit distinct lamella orientation distributions, mainly unimodal (for example, R. australis, R. brachyptera and R. osteochir), bimodal (for example, E. neucratoides and P. lineatus) and non-dominant (R. albescens). The dashed and dotted lines represent the median and the Q1 and Q3 quartiles, respectively (see Extended Data Fig. 1 for measurement). c, Host tissue stiffness of representative remora species: rays (R. albescens hosts, n = 4 statistics)^44,45, sharks (E. neucratoides hosts, n = 11 statistics)^46,47 and billfish (R. brachyptera hosts, n = 6 samples; see Supplementary Fig. 1 for details). The error bars represent mean ± s.d. d, Firm adhesion achieved as a live remora (E. naucrates) established only partial contact of its adhesive disc to an STP). Scale bar, 5 mm. e, Anatomy of a studied remora (E. naucrates) adhesive disc via high-resolution camera (scale bar, 5 mm), micro-computed tomography (μ-CT; scale bars, 5 mm (left), 500 µm (right)), microscopy (scale bar, 1 mm; n = 3 E. naucrates), and scanning electron microscopy (SEM; 300 µm (left), 100 µm (right); n = 3 E. naucrates). f, Distinct remora adhesion behaviours on hard and soft substrates. Left: illustration of remora’s adhesion to soft substrates via disc unfurling and mechanical interlocking for multicompartmental adhesion. Middle: high-speed image of remora’s adhesion to STP by unfurling its adhesive disc. Right: remora’s adhesion to polypropylene hard plate (PHP) via sliding and friction. Arrows (left and middle) indicate unfurling (also see Supplementary Video 1). Scale bar, 5 mm. g,h, Remora’s adhesion performance to soft and hard substrates under normal (g; n = 5 independent experiments) and shear (h; n = 5 independent experiments) directions. The error bars represent mean ± s.d. (top left insets in g,h illustrate the normal and shear adhesion test setups, with arrows indicating the direction of the force applied to the adhesion disks (white); see Supplementary Fig. 2 for details). RST, real pig stomach tissue; STP, stomach tissue phantom; PHP, polypropylene hard plate.