Howler monkeys at BFREE

A troop of howler monkeys was recently photographed from the observation tower.

A troop of howler monkeys was recently photographed from the observation tower.

By Jacob Marlin, BFREE Executive Director

Visitors and staff alike at BFREE are regularly serenaded by the sound of the Black howler monkey (Alouatta pigra). This species is conspicuous because their loud vocalizations carry for as many as three miles and they are therefore considered to be the loudest land animal on Earth. Male howler monkeys generally vocalize in order to mark their territory unlike other species that leave their sign with scrapes or scent on the forest floor or on trees.  Their roar can be eerie, giving the impression of a large almost prehistoric creature but when seen up close their relatively small size is surprising.  At BFREE, their vocalizations often startle visitors awake during the night and create quite an uproar during the day.

Howler monkey troop size ranges from 3-4 to over a dozen individuals with the sex ratio being one to three males to every seven to nine females. We currently have in residence at least seven troops within the immediate vicinity. Over the lifetime of BFREE, howler monkeys have continuously been present yet I have noticed over the past five years they seem to have become more accustomed to the field station and its human presence.

Troops range in size from 3 to over a dozen.

Troops range in size from 3 to over a dozen individuals.

Throughout much of its range the species has been declining due to hunting and habitat destruction. As the country of Belize develops and the pressure on resources increases, the slow but steady movement of humans into howler monkey territory, the species must retreat to sanctuaries where food availability and social structure is safeguarded.  The BFREE reserve serves this role for the species and though not intentional has become a sanctuary for this endangered species.

Recently, some of the staff at BFREE observed a newborn Howler monkey had fallen from a tree adjacent to the bunkhouse. We were able to capture the newborn on video. Watch it here.