Standard metabolic rate, the energy needed to maintain basic life functions, represents a large portion (~ 80%) of an ectotherm’s energy budget. In other words, SMR provides a good estimate of an organism’s basic maintenance costs (not including costs of digestion or activity). The energy spent on SMR varies according to many aspects of an organism’s natural operative environment, such as temperature fluctuations, but SMR can also be affected by anthropogenic disturbances to the environment. For instance, it has generally been suggested that exposure to xenobiotics results in the activation of energetically demanding physiological responses. If energy assimilation remains constant, allocation of additional energy to basic maintenance in contaminated environments detracts from energy that can be allocated to growth, storage, and reproduction, all of which are critical for sustaining viable populations.