Figure 5 in The Origin and Evolution of the Rattlesnake Rattle: Misdirection, Clarification, Theory, and Progress

Figure 5. Differences between values for respiratory activity of midbody and tail muscle reported by Moon (2001). VO 2 = rate of oxygen consumption, sdh = succinic dehydrogenase, and co = cytochrome oxidase (change in optical density). Moon (2001) reported raw values that were perhaps not intuitive to reviewers, and asserted that Agkistrodon contortrix displayed muscle oxidative capacities intermediate between tail-rattling colubrids (Coluber constrictor) and rattlesnakes (Sistrurus miliarius and Crotalus horridus). Plotting differences between mid-body and tail muscle measurements leads to a revised conclusion. Error bars = SD calculated as the square root of the sum of variances. The crosshatched bar is reported here as a positive number, but would have been negative as reported by Moon (a possible transposition).