Examination of temperature‐metabolism relations found no significant differences between thermoregulation of temperature housed laboratory cotton‐top tamarins ( Saguinus oedipus ) and wild tamarins in Colombia, S.A. The results indicate that tamarins do not acclimate to a temperate environment and are metabolically stressed at T a less than 32°C. This is consistent with an hypothesis of chronic metabolic stress as a factor in the etiology of cotton‐top tamarin colitis, which is restricted to captive populations and not found in wild tamarins.