Fig. 3. Most common strain patterns during suction and biting in Polypterus, mapped onto a three-dimensional reconstruction of the skull made from the microCT scan of fish no. 2. Lengths of vectors are proportional to the strains they represent (see scale bar). The percentages indicate how frequently each pattern is observed during suction and biting. Double-headed arrows indicate a shift in strain polarity within a single event. In spite of the variation in strain patterns in suction and biting, the interfrontal (IF) is consistently loaded in tension, while the interparietal (IP) is compressed. The frontoparietal (FP) suture may be loaded in tension or compression, or may shift from one to the other, within a single feeding event. The maximum (E1) and minimum (E2) principal strains on the left frontal bone are also shown.