To investigate a possible link of malignant hyperthermia to capture myopathy, between June 1990 and July 1993 we anesthetized four black-tailed deer (Odocoileus hemionus columbianus) and challenged them with halothane and succinylcholine. Halothane had no significant effect on oxygen consumption. Succinylcholine significantly (P < 0.05) increased cardiac output (mean ± SD), from 2.94 ± 1.05 1/min to 5.26 ± 1.79 1/min, and oxygen consumption, from 5.5 ±2.1 ml/kg/min to 10.1 ± 2.9 ml/kg/min. Muscle biopsy specimens tested for malignant hyperthermia susceptibility responded normally to halothane and caffeine. We conclude that these deer did not experience malignant hyperthermia, suggesting no link to capture myopathy.