Table 1.
Summary of parameters of prey attack for snakes in different occlusive conditions.
Figure 1.
Performances of control conditions.
Plots of all strikes (unfilled squares) for snakes in the control condition indicating strike distances (cm) and angles (°). The filled square represents the mean strike distance and angle in the control condition.
Figure 2.
Performances of eight occluded conditions.
Plots showing distances (cm) and angles (°) of individual strikes (unfilled symbols) and mean values (filled symbols) in the occlusion conditions: A: Binocular occlusion (blue unfilled circles and red filled circle) vs. bilateral pit organ occlusion (green unfilled triangles and red filled triangle). B: Left eye and pit occlusion (blue unfilled circles and red filled circle) vs. right eye-pit occlusion (green unfilled triangles and red solid triangle). C: Contralateral occlusion of the left eye and right pit organ (blue unfilled circles and red filled circle) vs. contralateral occlusion of the right eye and left pit organ (green unfilled triangles and red solid triangle). D: Unilateral opening of only the right pit (blue unfilled circles and red filled circle) vs. unilateral opening of only the left pit organ (green unfilled triangles and red filled triangle).
Figure 3.
Schematic diagram of the two imaging sensory circuits.
Schematic diagram of the snake brain (anterior is up and posterior is down) illustrating visual (blue) and IR (red) pathways showing convergence of visual (blue) and IR (red) inputs in the contralateral tectum. Abbreviations: LTTD, nucleus of the lateral descending trigeminal tract; RC, nucleus reticularis caloris; TeO, optic tectum. The arrow interconnecting the left and right optic tectums represents the tectal commissure and the filled triangle in the tecta represents the tectal bimodal neuronal population (see text).
Figure 4.
Positions of pits and eyes and demonstrate of sensory occlusion.
A: Photograph of the head of Gloydius brevicaudus showing the location of the lateral facial pit organ between the ipsilateral eye and nostril. B: Photograph of the rostral view of the head of G. brevicaudus showing both eyes and facial pits. C: A photograph of an experimental subject illustrating left side sensory occlusion (see Materials and Methods for explanation).
Figure 5.
Demonstration of experiment and recording.
A schematic diagram illustrating the experimental set-up used to measure behavior during targeting trials. A camcorder mounted on a tripod and connected to a PC was used to record the behavior of the snakes. A grid superimposed on the image was used to quantify strike distances and angles. At the beginning of each trial a mouse of appropriate size was placed directly in front of the head of the snake at the edge of the arena (see Materials and Methods for explanation).