This page was done as part of an assignment
for Animal Behavior at Davidson College.
The six species of Howler monkeys
live in wet evergreen and semideciduous habitats in areas ranging from
southern Mexico to northern Argentina (Smuts et. al., 1987). Howlers
live in forest and are mostly arboreal (Smuts et. al., 1987). Their
diet consists mostly of fruits and leaves. Brown howlers studied in southeastern
Brazil were observed feeding 18% of daylight hours and moving around 13%
of the time (Chiarello 1993). More time was alotted to eating in
the wet season than the dry season. Additionally the more time the
howlers spent eating young leaves, the more time was spent resting (Chiarello
1993). In contrast, the more time the monkeys spent eating mature
leaves the more time they spent eating (Chiarello 1993). These
observations can be explained by the fact that younger leaves have more
energy readily availible for use than the mature leaves (Chiarello 1993).
It is also suggested that the monkeys are not that efficient in deriving
energy from the leaves they consume for two reasons: 1)the leaves have
a low energy content and 2) howlers lack a specialized digestive tract
to break down the leaves (Chiarello 1993).
In another group
of red howler monkeys, only 12.7% of the time was spent eating while the
monkeys were resting 78.5% of the time (Gaulin 1982). Young leaves
were preferred over mature leaves and ripe fruit was preferred over young
fruits. Over half the time spent eating was spent consuming young
leaves but more fruit was consumed overall (Gaulin 1982). These red
howlers ate 4 distinct meals a day separated by 2 hour periods of rest
(Gaulin 1982).
In a study of
mantled howler monkeys studied in a forest fragment in Los Tuxtlas, researchers
found that the monkeys ate 52 different species of plants through out the
1 year they were observed (Estrada et. al. 1999). 67% of the plants
were trees. Leaves and fruits were consumed 96% of the total feeding
time (Estrada et. al. 1999). 63% of the tree species consumer by
the howler monkeys were uniformly dispersed, and 26% were aggregated, and
11% were randomly dispersed (Estrada et. al. 1999). Overall food
is very abundant in the plush forest environment.
This page was done as part of an assignment
for Animal Behavior at Davidson College.