Roaring occurs after two red howler monkey troops confront one another.
(http://web.missouri.edu/~anthmark/redhowl.htm)
Roaring occurs after two red howler
monkey troops confront one another.
(http://web.missouri.edu/~anthmark/redhowl.htm)
Howler monkeys reside in troops on
home ranges. These home ranges can be as small as 5 ha and as large
as 60 ha, but usually they are between 10 and 30 ha(Smuts et al. 1987).
Home range is very variable and varies more within a species than among
the 6 different species(Smuts et al. 1987). A study of the mantled
howler monkey suggests that they travel as little as possible and are energetically
constrained as a result of their low energy foliage diet (Smuts et al.
1987). Home ranges of red howlers were observed to overlap as much
as 63%. Home ranges of mantled howlers can overlap as much as 100%
(Smuts et al. 1987). Some researchers do argue that howlers exibit
territoriality despite this dramatic overlap in home range because of the
intergroup interactions observed in red howler monkeys (Smuts et al. 1987).
Troop interaction is usually characterized by loud roars exchanged between
2 opposing troops. These roars are very loud and it is suggested
they are the most energetically expensive thing that howlers do (Smuts
et al. 1987). Troop displacements are rare, but one troop may be
forced to retreat a small distance from the altercation site (Smuts et
al. 1987). The purpose of the dawn calls that howlers make in the
early morning is to to make other troops aware of the various locations
of the surrounding troops. Eventhough howlers appear to hold claim
on a certain area, they are suggested to be energetically constrained from
defending an exclusive territory (Smuts et al. 1987).
One 20-year study
of mantled howlers in Costa Rica showed that the average size of home range
was 27.2 ha and home range correlated most closely with the number of adults
in the troop (Zucker et al. 1996). The various troops that were studied
appeared to stay on the same home ranges through the 20 year study period
(Zucker et al. 1996).
This page was done as part of an assignment
for Animal Behavior at Davidson College.
