A study of the 24‐hour cycle of activity in Capybaras in the llanos of Venezuela was made using visible red light for nocturnal activity. Observations were made during both the dry and rainy season. In both cases Capybaras showed 4 peaks of activity during the 24‐hour cycle, but in the dry season 3 peaks were after dark while in the wet season 2 peaks were by day and 2 by night. By night groups of Capybaras moved rapidly to grazing sites keeping together by low volume vocal communication. Experimentation showed that visible red light permits close approach to Capybaras because it hides the observer. Coprophagy was frequently observed, almost exclusively during the morning resting period. Copulations were observed mostly in May (dry season), all but one in water, and most between 08.00 to 13.00. It is suggested that censuses for establishing harvest quotas avoid resting periods because important proportions of Capybaras may be hidden in thickets or aquatic vegetation.