Fig. 2. Effects of routine laboratory procedures and simulated `natural' stressful events on (A) plasma corticosterone levels and (B) breathing rates, of water skinks (Eulamprus heatwolei). Stimuli are described in the text. Groups A–D in A are significantly different from one another, and are discussed in the text. Blood samples were taken 1 h following exposure to the potentially stressful stimulus. Each sample consists of 20 animals (10 males and 10 females), with data shown separately for male and female lizards. Values are means ± s.e.m.