Ventral surface exposure of the two side-biased groups on a wide pole, as a function of threat-approach direction.

<p>Exposure (mean ± SE) under right- or left-approaching threats, for chameleons of the right-biased (N  = 10) and left-biased (N  = 7) groups, in tests on a wide pole at the onset of pole rotation (Initial), end of pole rotation (Rotation end), and end of test (Final).</p

Eye durations (proportions) of the Leading Eye or the Following Eye in viewing categories FV or NV.

<p>The durations as a function of threat approach direction. Provided are ANOVA test results.</p

Avoidance response patterns of the two side-biased groups on a narrow pole.

<p>Ventral surface exposure (mean ± SE) on narrow poles in response to right- or left-approaching threats in chameleons of the right-biased group (10.1, N  = 14) and of the left-biased group (10.2, N  = 10). Exposure readings are at 200-ms intervals, (A) at the onset of pole rotation, (B) at the end of pole rotation, and (C) at the end of the test.</p

Chameleons’ ventral exposure as a function of threat-approach direction.

<p>The ventral surface exposed to a right- or a left-approaching threat at the onset of pole rotation (Initial), end of pole rotation (Rotation end), and end of test (Final).</p

A model of hemispheric dominance relationships and the resulting levels of body exposure, during avoidance behavior, in the two side-biased sub-groups.

<p>For a given hemisphere (R.H. – right hemisphere, L.H. – left hemisphere, light gray), the relative excitation is high (H) low (L) or none (N), as a function of eye role (L.E. –leading, F.E. – following). The direction of the arrows depicts the direction of inter-hemispheric dominance. Eyes marked with an X could not view the threat due to the visual obstruction by the relatively wide pole.</p

The range of eye apertures for the different viewing categories.

<p>Frontal viewing (FV), from circular to oval-shaped eye opening (respectively ca. 100% to ca. 20% of the maximum). Peripheral viewing (PV), from oval to slit-shaped eye opening (respectively ca. 20% to ca. 0%). Not visible (NV), eye opening cannot be observed. Reprinted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0070761#pone.0070761-Lustig1" target="_blank">[33]</a> under a CC BY license, with permission from Springer, original copyright 2012.</p

Eye shift frequencies (mean/test) between the three viewing categories (FV, PV or NV).

<p>The results pertain to i) Lines 1–2: the frequencies as a function of threat approach direction (columns 3–5) and pole width (columns 6–8), ii) Lines 3–4: the frequencies as a function of threat approach direction (columns 3–5) and eye role (columns 6–8). Provided are ANOVA test results.</p

Latency of response of the two side-biased groups as a function of threat-approach direction.

<p>Latencies (mean ± SE) to final exposure of chameleons of the right-biased and left-biased groups, under right- or left-approaching threats, on narrow or wide poles (respective number of chameleons tested: 14, 10, 10, 7 for groups from left to right).</p

Ventral surface exposure used in the avoidance response analysis.

<p>A single frame from a sampled video sequence is depicted. (A) Unmodified image showing the ventral view of the chameleon holding onto a narrow pole, with its eyes protruding from both sides of the pole. (B) Body surface of the chameleon with the areas exposed on each side of the pole (hatched) used for the determination of respective surfaces. The caudal border of the area analyzed (broken horizontal line) is determined on the basis of 3×maximal head width, from the rostral end.</p

The experimental setup (a – oblique view; b – schematic overhead view).

<p>The experimenter, positioned behind the camera (A), acts as the threat stimulus. Chameleon (X); vertical, rotatable pole (B); incandescent lights (C); pole rotation cords (D); visual barrier (E); screen (F). Reprinted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0070761#pone.0070761-Lustig1" target="_blank">[33]</a> under a CC BY license, with permission from Springer, original copyright 2012.</p