AlsocalledCaraya in Guaranilanguage. Itsname comes fromthestrongroarthattheymakeaerly in themorning and at dusk in ordertomarkterritory and it can be Heard severalkilometersaway. Thereis a cleardifferencebetween males (black and big) and females/youngs (yellow). Theirdietisbasedonleaves, fruits and flowers.
Theyformgroups of 10-12 individualsapproximatelycomposed of a alphamale, severalfemales and theirbabies. In the Ibera, a notable featureisthateach of theseclansoccupies a wholeforest.
Theperiods of activity are aroundnoon in winter, and duringthemorning and evening in summer, when temperaturas are more pleasant.