EnglishThe mantled howler monkey (Alouatta palliata) is a New World Monkey, one of the five families of primates residing in South and Central America as well as Mexico.
It has characteristics that make it seem more threatening than it is. The species is marked by a large, stocky body and a roar so loud, it has been compared to that of a lion! But they don’t pose a risk to humans.
Though they play an important role in the ecosystem, their numbers are quickly dwindling.
In this article, Paso Pacifico describes the threats they face and what we can do to save mantled howler monkey habitats.
Mantled Howler Monkeys and Their Habitats
Mantled howlers are native to the southern tip of Mexico as well as Central and South America.
You can find these primates in Campeche, Chiapas, Colombia, Costa Rica, Honduras, Oaxaca, Panama, Tabasco, Veracruz, and western Ecuador. Their homes are primary and secondary forests, coastal lowland and montane rainforests, gallery forests, mangrove forests, cloud forests, and dry deciduous forests.
They prefer the canopy layer of forests where most of their food can be found.
Fascinating Facts About the Mantled Howler Monkey
Here are some memorable characteristics of the mantled howler monkey:
They Are Arboreal
Mantled howlers live in trees and are seldom seen walking on the ground.
Their movements (walking, running, and galloping), which often display their quadrupedalism (moving on four feet), are driven by canopy structure, resource location, and topography. They also exhibit bridging (stretching to cross gaps) and suspend themselves by their arms.
Mantled Howlers Are Herbivores
Mantled howler monkeys are the most folivorous of New World primates. Beyond munching on fruits, nuts, buds, and flowers, they also get their nutrients from living leaves and petioles.
Their diet can vary seasonally with fluctuating availability. Generally, these monkeys prefer food with the lowest tannins and highest protein.
They Are Large and Stocky
Mantled monkeys are large, stocky, and mostly covered in black, save for the two long, yellow, or brown cloak-like patches on their flanks where they get their name from.
Their faces are mostly bright and bare, with a dark beard-like growth that is typically longer in males than females. They’re also sexually dimorphic, so there are other morphological differences.
Mantled Howlers Are One of the Largest Monkeys in Central America
Male mantled howlers are between 20 and 27 inches long and weigh as much as 30 pounds. Their female counterparts have body lengths from 18 to 25 inches and weigh as much as 16 pounds.
These Monkeys Are Polygynous
Mantled howlers have a polygamous mating system. One male breeds with multiple females. Each female gives birth to a single offspring after a gestation period of 186 days or about 6 months.
Mantled Howler Monkeys Don’t Drink Groundwater
Mantled howler monkeys get most of their water from their food.
During the dry seasons, when the leaves they consume contain significantly less water, they rely on arboreal water cisterns for hydration. However, since cisterns are only available during monsoons, these monkeys climb down occasionally or alter their schedules to compensate for the difference.
They Have a Complex Hierarchy
Communities of mantled howlers are led by male members of the species. Young male adults have the highest ranking followed by middle-aged male monkeys while the oldest male members are at the bottom of the chain.
These Primates Have an Incredibly Loud Cry
Hyoid bones in male mantled howlers are larger than those found in females, allowing them to make loud, guttural calls. Their cries are used to locate fellow howlers and communicate from a distance.
The fearful sound is almost as powerful as a lion’s roar and can be heard up to 3 miles away.
Mantled Howler Monkeys Have Long Lifespans
Mantled howlers can live 20 to 25 years in the wild. Unfortunately, not many members of the species live this long. Eighty-eight percent of males and 65% of females die before age five. Some hypothesize that their premature mortality may be due to food scarcity.
They Have Prehensile Tails
Mantled howler monkeys have a thick, furry prehensile tail that’s hairless on the underside. It provides them with a solid grip as they move between branches and trees in search of food, functioning like a fifth limb.
Mantled Howlers Live in Groups
They exhibit social behavior and live in mixed-sex groups that can have as many as 40 members! They have a high female-to-male ratio, with nearly 4 females for every male. If the number of females in the group drops, older males become aggressive towards infants to drive them off.
These New World Monkeys Sleep Most of the Day Away
Leaves have hard-to-digest cellulose and are low in sugar, providing less energy than most food. Mantled howlers spend the majority of the day saving their energy for more important tasks like foraging.
Are Mantled Howler Monkeys as Aggressive as They Seem?
The mantled howler monkey’s chasing behavior, female-to-female agonistic interactions, and male-to-male fights are well documented. There have also been shocking reports of infant-killing following a male takeover.
Combined with their loud calls, it’s easy to see why people are intimidated. But that doesn’t mean that they’re extremely dangerous.
Mantled howler monkeys exhibit rare aggressive behaviors. They have some of the lowest levels of conspecific aggression reported for any social primate! However, they will defend themselves if cornered.
Threats They Face
Mantled howler monkeys are experiencing a sharp population decline because of predators. They’re also hunted for pet trade and bushmeat, and face competition from spider monkeys, wooly monkeys, and leaf-cutting ants.
Their greatest threat, however, comes from habitat loss and fragmentation. These occur as agriculture, livestock farming, and economic development lead to deforestation. Studies suggest that if the current rate of deforestation continues, the species will lose 73% to 84% of its suitable range in the next three decades.
While they can survive in disturbed anthropogenic ecosystems, which include forest fragments as small as a few hectares, research suggests that they may not thrive in these conditions in the long term. As viable habitats become smaller and scarcer, mantled howler monkeys become more susceptible to epidemics, nutritional stress, genetic stochasticity, poor reproductive performance, and environmental catastrophes.
How You Can Help Mantled Howlers Thrive
Mantled howler monkeys are listed by the International Union for Conservation of Nature (IUCN) as “vulnerable.”
We need to preserve their populations, especially in light of the role they play in the ecosystem. Mantled howlers disperse seeds from various fruits and veggies through their excrement, which increases species diversity in their habitats. Conserving their homes can also improve the survival rate of other species that rely on plant diets.
Given the wide geographical spread of their habitats, efforts can be challenging to coordinate and execute.
However, you can still help preserve the areas where they live by:
- Spreading awareness about the important ecological role they play
- Creating wildlife crossing roads (rope bridges) to prevent or minimize road accidents and injuries from power lines
You can also help Paso Pacifico.
How Paso Pacifico is Preserving Mantled Howler Monkey Habitats
From drought to deforestation, many factors threaten the habitats of mantled howler monkeys. Paso Pacifico is doing its best to address them by protecting habitats in the Pacific Slope ecosystems of Mesoamerica.
We work with governments, agencies, and institutions to highlight the plight of mantled howler monkeys and the issues behind their dwindling numbers.
In 2016, we began working with UC Davis primate specialists to identify risks to their population. We also set up water and fruit stations across dry tropical forests and spearheaded a reforestation campaign in San Juan Del Sur.
Mantled howler monkeys deserve homes too. Donate to our programs.