New Arrival: Marlie, Southhern Black Howler Monkey

Lincoln Park Zoo is ready to get loud about the zoo’s latest resident! Helen Brach Primate House has welcomed Marlie, a five-year-old male southern black howler monkey (Alouatta caraya) from Houston Zoo.

Marlie previously lived with his parents and siblings and was recommended to come to Chicago by the Southern Black Howler Monkey Species Survival Plan®. He is currently learning to be a companion to 26-year-old Otra. The two have been bonding and can be seen grooming and huddling with one another in their habitat.

Southern black howler monkeys are the largest—and loudest—monkeys in Latin American rainforests. They are considered Near Threatened on the International Union for the Conservation of Nature’s Red List as a result of human development, hunting, and disease outbreaks.

Males have black coats, while females have blond fur and are slightly smaller. They vocalize to claim feeding trees in their home range every day, and can be heard three miles away when they are roaring together. Their large hyoid bone (Adam’s apple) helps amplify their calls, but also limits mobility in their arms. Fortunately, their tails are prehensile and act as a fifth limb, allowing them to grasp tree limbs to balance and even hang from their tail. The tail can support the monkeys’ entire body weight when they are feeding, playing, or physically interacting with other monkeys.

Southern black howler monkeys are also known as the only New World primates that regularly eat mature leaves, which can help them adapt easily to new environments and travel less per day than other primate species. They metabolize this food with a highly evolved digestive system, which allows more efficient fermentation and breakdown of difficult plant fibers. Even so, they rest half the day—that way, they don’t use up too much energy, since they only receive limited amounts of calories.

The howling, in fact, helps them expend less energy by broadcasting their location to other howler monkeys. This reduces their need to patrol territory or defend it from other howler monkey groups.

After mating, female howler monkeys give birth every two years after a 180-day gestation period. Infants are born blonde and then males turn black at around two and a half years of age. However, Otra and Marlie will not be a breeding pair.

If you come to the Primate House to visit the new addition, be sure to look up! The howler monkeys have a new window platform in their habitat and might be found there. They are easy to tell apart: Otra will be the one with golden fur and Marlie has a shiny, pure black coat.