Fig. 4. Mean peak strains across the interfrontal (IF), interparietal (IP) and frontoparietal (FP) sutures, and maximum (E1) and minimum (E2) principal bone strains during suction and biting. Values are means ± 1 s.e.m. Filled symbols are strains measured in suction, and open symbols represent strains measured during biting. (circles, Polypterus 1; squares, Polypterus 2, triangles; Polypterus 3, diamonds; Polypterus 4). Black symbols are the mean of means for all four fish (± 1 s.e.m.). The most common strain pattern during suction is shown (inset). Mean peak IF, FP and IP strains are higher during suction than during biting. In addition, E1 is larger during suction than in biting, but there is no difference in the E2 in suction and biting.