Mantled howler

Mantled howlers live in rainforests.

They live in Mexico, Central America and parts of South America.

Mantled howlers live from southern Mexico and Guatemala through Central America to Colombia, western Ecuador and Peru in South America.

They live in many kinds of forest, from the lowlands up to about 2,000 meters in the mountains: rainforest, cloud forest and forest that has grown back. Where forests have been cut down in southern Mexico, some howlers now live in the shady trees of cacao and coffee farms.

Animal Diversity Web gives the range as southern Mexico (Veracruz, Campeche, Chiapas, Oaxaca and Tabasco) and from Honduras through Central America to Colombia and western Ecuador, noting only unconfirmed reports from southern Guatemala; the IUCN assessment (Cortes-Ortiz and colleagues, assessed 2015, published 2021) lists Guatemala and Peru as well. The IUCN gives an elevation range of sea level to 2,000 meters (ADW, after Reid 1997, says up to 2,500), covering primary and regenerating lowland and montane rainforest.

In Costa Rica, two troops in the same area chose habitat differently: one used primary forest 80 percent of the time, while the other preferred undisturbed riverside forest. Under forest fragmentation, many howlers in southern Mexico have moved into shaded cacao and coffee plantations.

Howlers eat leaves, fruit and flowers.

They like young, soft leaves best.

Mantled howlers eat mostly leaves, fruit and flowers, almost all from trees. They spend about as much feeding time eating leaves as eating fruit. In the dry season they eat more flowers, and in the wet season more fruit.

They are picky! They choose young leaves, which have more protein and fewer bitter chemicals called tannins. Leaves give little energy, so howlers move slowly and rest a lot to save energy.

The diet is mainly leaves, fruit and flowers, varying with season: flowers are plentiful in the dry season and fruit in the wet (Animal Diversity Web). Feeding time is split almost equally between leaves and fruit, and howlers preferentially take young leaves with a higher protein-to-fiber ratio and lower tannin content.

Food choice depends on digestibility, nutrients and secondary compounds; sampling new foods may add species to a troop's diet and track seasonal changes in plant chemistry. ADW links the leaf-heavy diet to an energetically conservative lifestyle.

Howlers live in groups.

At sunrise and sunset, they howl very loudly to tell other groups where they are.

Mantled howlers live in troops of about 10 to 20, with one to three adult males and five to ten adult females. Most young howlers, females and males, leave the troop they were born in. Once a female settles into a new troop, she usually stays for life.

Their famous howls ring through the forest at dawn and dusk, and whenever something disturbs them. The calls help neighboring troops keep their distance. Howlers also woof, grunt and bark.

Troops number about 10 to 20: one to three adult males and five to ten adult females. Females form the stable core and rarely leave once established, while immigration drives group growth more than births (Animal Diversity Web). Hierarchies are linear, and dominant individuals groom subordinates.

Spacing between troops depends partly on vocal exchanges between males. Calls include woofs, grunts, barks and the characteristic howls, given at dawn and dusk and in response to disturbance.

Listen to the recording at the start of this page.

It is real mantled howlers, recorded in Costa Rica.

At the start of this page you can play a real recording of mantled howlers calling in Santa Rosa National Park, Costa Rica.

Troops howl at dawn and dusk, and when something disturbs them, to tell neighboring troops where they are. Howlers also make woofs, grunts and barks. Listen closely: how many different voices can you hear?

The recording on this page is of mantled howler calls in Santa Rosa National Park, Costa Rica. Animal Diversity Web lists woofs, grunts, barks and howls, with howls given at dawn and dusk and in response to disturbance, and notes that male vocal exchanges help space neighboring troops.

Howlers need forests.

Many forests are being cut down. People are making new reserves to help.

The mantled howler is listed as Vulnerable. Its rainforests are being cut into small pieces, and some troops are left in tiny patches or on farms. Storms and other natural disasters can hit small groups hard.

Scientists suggest protecting existing reserves better, creating new ones, moving howlers to safer forests when needed and teaching people about them.

The IUCN lists Alouatta palliata as Vulnerable, with a decreasing population (assessed 2015, published 2021). Animal Diversity Web notes it is listed as endangered under the U.S. Endangered Species Act and on CITES Appendix I, and that forest fragmentation has pushed many howlers into shaded cacao and coffee plantations, especially in southern Mexico.

Cortes-Ortiz and colleagues (1996) recommended better management of protected areas, new reserves, translocation, management of populations in fragments, controlling human traffic and education. Continued declines could affect rainforest regeneration.