Howler monkeys are the largest new world monkeys. They weigh up to 22 pounds and have hairless, prehensile tails, that are used to grip and help swing from trees. They also have large hyoid bones(Adams apple) that house their vocal cords and help produce  a very loud call, that is one of the loudest calls made by  any land animal. Howler monkeys have short snouts and beards and long thick hair, that can be black, brown or red. 

Red howler monkeys can be found in a large variety of habitats within its range.  Including tropical forests, including rain forests, deciduous forests, and mangrove swamp. They prefer lake and river edge habitats. The species is found at high altitudes ,most of the time, but can also be found low to the ground foraging for food on occasion.They are not as active as other monkeys. They tend to sit in the tree tops for hours eating leaves.

Red howlers are vegetarians and predominantly frugivorous, consuming mainly fruits, fruit pulp and fruit leaves supplemented by roots, flowers, seeds and berries. They prefer medium or large fruits that are brightly colored. They also prefer young leaves over older ones. This species is also an important seed dispersal mechanism for the plants which it consumes. Fruit availability is very seasonal. As a result, at different times of the year, red howlers eat more vegetation than they do fruit and vice versa. 

Red holder monkeys are famous for a deafening roar that can be heard up to 5 km away! They use their sound to announce to  They live in social groups up to 10 members. They are most active in the mornings and evenings. They cover about 400 meters per day , eating in the tree tops.

Humans are the greatest threat to these monkeys due to deforestation and habitat loss, disease, and hunting.Human development are the leading causes of deforestation. Red howlers are also hunted for food, pet trade and traditional medicine. Predators also include jaguars , pumas , eagles , snakes, dogs and coyotes.