Figure 4. Contact areas of the two frog species at 5 tilting positions.

Using a special illumination technique (see Materials and Methods), the contact area of ventral body parts (toe pads, belly, thighs and uncategorised areas) of (A) the tree frog (R. pardalis) and (B) the torrent frog (S. guttatus) was measured at 0°, 45°, 90°, 135° and 180°. The photos at the top are images of the frogs at horizontal (0°) and inverted (180°) tilting positions. The plots represent medians of 42 trials from 6 frogs (tree frogs) and 33 trials from 6 frogs (torrent frogs), the percentages at the top representing the proportion of frogs still attached at each tilt angle.).