The article discusses a study on the attacks of culpeo, Lycalopex culpaeus, against small guanacos, Lama guanicoe and cooperative defense by guanacos living in Tierra del Fuego in Argentina and Chile. The culpeo is considered as the only terrestrial predator in the area, weighing up to 14 kilograms and lives with pumas and guanacos. It is noted that cooperative defense by guanacos are usually seen during the first weeks after birth because small guanacos are vulnerable. The study suggested continued monitoring of culpeo attacks.