Chapter 1, The Reptilian Spectacle - UWSpace - University of ...

Figure 2-4. Experimental setup. A: the
whole imaging system with the snake in
a holding box (the curtains that obscure
the experimenter are not shown). B: a
coachwhip snake with its eye next to the
pane of the holding box.
To prevent the snake from observing the experimenter, curtains were mounted on the slit-lamp
table, which allowed only the slit-lamp objectives and illumination arm to be visible to the snake. Thus
hidden, the experimenter was free to manipulate the controls of the slit-lamp and enter data without
visually alerting the animal.
2.2.3 Experimental Protocol
Animals were left to acclimate in the transparent box for 30 minutes prior to data collection, during
which time the box and slit-lamp were adjusted to bring one of the animal’s eyes into view. After this
setup and acclimation time, the experimenter began recording to the nearest second the times when
blood flow in the spectacle began and stopped. Owing to the transparency of the spectacle blood vessel
walls, it proved difficult to reliably observe their constriction and dilation, so the presence and absence
of erythrocytes was used instead as the measure. Data were recorded for 70 consecutive minutes.
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A
B