Black Howler Monkey
(http://www.animalsoftherainforest.org/howlermonkey.htm)
Red Howler Monkey
(http://www.animalsoftherainforest.org/howlermonkey.htm)
Male and Female Black Howler Monkey
Despite the name, only the males have a black
coat color. The females and young offspring have a golden brown fur.
(http://www.honoluluzoo.org/howler_monkey.htm)
General Description and Social
System
There are 6 different species
of howler monkey, genus Alouatta, including mantled howler (Alouatta
palliata) , black howler (Alouatta caraya), red howler (Alouatta
seniculus), brown howler (Alouatta fusca), red-handed howler
(Alouatta belzebul) , and Guatemalan howler (Alouatta pigra)
(Smuts et al. 1987). Adult howler monkeys weigh up to 10 kg but
can be as small as 4 kg (Smuts et al 1987). Male black howlers weigh
16 pounds on average while females weigh only 12.5 pounds (Oregon
Zoo web site). Males are between 18 and 28 inches tall and females are
between 15 and 22 inches tall (Oregon Zoo web site). Howler
monkeys exhibit dimporphism in which the male is larger than the female.
Howler live in troops of between 5 and 20 individuals and there are usually
more females in the troop than males (Smuts et al 1987). Some troops
may only have one male member (Smuts et al 1987).
The name howler
monkey is derived from the characteristic long calls these primates make
an enlarged hyoid bone which acts like a resonator. In troops of
Alouatta palliata living in Panama, males were found to make the
loudest calls (Baldwin et al 1976). Every morning the howlers performed
a characteristic dawn chorus in which the members of the troop call out
in synchrony (Baldwin et al 1976). Roars given during the day were
observed in the following instances: nonmixing troops were in close proximity
or were moving closer to one another, a silent troop suddenly made vocalizations,
dogs approached a troop, wind and rain were present, and following midday
naps (Baldwin et al 1976). Completely spontaneous calls and roaring
were observed in members of a troop, which sometimes provoked another troop
to respond (Baldwin et al 1976). Generally these howler troops used
these spontaneous calls in order to inform other troops of their location
so that encounter can be avoided (Baldwin et al 1976). If two troops
do come into contact, troops roar at each other before retreating (Baldwin
et al 1976).
Habitat and Habitat Utilization
This page was created by Sara Brautignam as part of
an assignment for Animal Behavior at Davidson College.
