The Venezuelan Red Howler Monkey (Alouatta seniculus) is a South American species of howler monkey. It is found in the western Amazon Basin in Venezuela, Colombia, Ecuador, Peru, Bolivia and Brazil. It is the largest monkey in South America reaching up to 3 feet and and 25 pounds. His prehensile tail helps it to hang on to the trees, where it spends most of the time feeding, mainly on leaves, although it also eats flowers and some fruits. It is the leaves that contribute mainly to its survival, as it can live on them for weeks without needing to go down to the ground for water. It manages to utter its heaven-rending howls thanks to a highly developed bone in its throat that acts as a soundbox. It gives these calls to defend its territory and also to warn of predators, man, mainly and some felines.
The male is larger than the female and its large jaw is immediately apparent.  They live in social groups op to 10 individuals with one or two males, at most.

A male Howler Monkey moving through the branches, showing his prehensile tail, then eating leaves of the balsam tree. A male resting on a tree and a close up with its big jaw and the whole group resting on the tree tops. The  sexual behavior is interesting. The male and female engage in a courtship ritual in a small area before mating, and, once the associations have been established, the male solicits the female and they proceed to mate. This time we were lucky and were able to get it on film. At last we have the Howler Monkeys calling with its deafening sound that can be heard many miles away, there are at the same time territory calls and fear calls by the presence of intruders. The sound of the Howler Monkey is the strongest on earth, only surpassed by the songs of  biggest animal that roamed the earth, the Blue Whale.

El Mono Aullador (Alouatta seniculus) de América del Sur se encuentra en la cuenca occidental del Amazonas en Venezuela, Colombia, Ecuador, Perú, Bolivia y Brasil. Es el mono más grande en Sudamérica, pudiendo alcanzar un metro de largo (sin contar la cola) y unos 10-12 Kg. Su cola prensil le ayuda a treparse a los árboles, donde pasa la mayor parte del tiempo alimentándose principalmente de las hojas, aunque también come flores y algunas frutas. Son las hojas las que contribuyen principalmente a su supervivencia, ya que pueden vivir de ellas durante semanas sin necesidad de bajar al suelo por agua. Sus desgarradoes aullidos son producidos gracias a un hueso en su garganta que actúa como un caja de resonancia. Lo llamados son producidos para defender su territorio y también para advertir de la presencia de depredadores, el hombre principalmente, el Aguila Harpía  y algunos félidos. El macho es mayor que la hembra y su gran mandíbula es inmediatamente evidente. Viven grupos sociales de hasta 10 individuos,  con uno o dos machos a lo sumo.