Blog Post 2 | Red Howler Monkey

Alouatta                                                                                                                               seniculus                                                                            Red 

Howler 

                             Monkey

Geographical Range 

The red howler monkey (Alouatta seniculus) has a pretty broad geographic distribution across northwestern South America, Living across regions in tropical forests.

   

                           Venezuela                                                                                Colombia
                Most regions of country.                                                 Most regions of country Excluding: 
         Regions around Lake Maracaibo.                                        Pacific region, Guajira Desert, Nariño. 
                   Mérida Mountains.                                                           Can live in Higher Elevations.
             Northwest of Bolívar State.                                                The Colombian Andes Mountains.
 

               Ecuador and Peru                                                                               Brazil
 Large Portions of Amazon Rainforest.                                                        Northern Brazil.
        Up to the Brazilian border.                                                                Amazon Rainforest. 
 Rio Negro = boundary of northern range.                                               Dense Canopy Forest.



Habitat

Red howler monkeys are well-adapted to life in the canopy layer of tropical rainforests and moist forests. They are arboreal (tree-dwelling) and rarely venture around through the forest floor.

  • Vegetation: As they are mostly found in tropical rainforests, these forest provide dense canopies which supports a wide variety of vegetation types I.E deciduous trees, palms, and lianas. An adequate habitat would be one that offers large amounts of foliage and tall trees, these allow them to stay hidden from predators.
  • Home Range: The home range of the red howler monkeys varies from 25 to 50 hectares depending on the density of vegetation and food sources available. They make use of patches of very dense tree cover in their range, which shelters them from predators and inclement weather.
  • Day Ranges: These monkeys typically travel slowly through the trees, covering several kilometers a day as they forage for food, but they are not known for long-distance traveling. They tend to stay in their home range unless disturbed or when food becomes scarce.

    • Locomotion

    Red howler monkeys have evolved for a life spent primarily in the treetops. Their locomotion is characterized by both quadrupedalism and suspensory behaviors, with the tail playing a key role in supporting their movement.

            Prehensile Tail                                                                                             Quadrupedal
         Strong and flexible.                                                                                   Uses All four limbs to:
        Acts as a fifth limb.                                                                             Move along branches and limbs.
    Holds onto branches for:                                                                   Long and muscular limbs are used for: 
      Foraging and traveling.                                                                       Balance, climbing and grasping trees.

               Suspensory                                                                          
         Canopy navigation.                                               
       Forearms, hands, tail.     
      Swinging + suspension.
     Large trees through gaps.


    Ecology

    The red howler monkey plays a significant role in its ecosystem, primarily as a herbivore, with its slow and deliberate lifestyle contributing to the structure of forest habitats.

    • Diet: Red howlers are primarily folivores but also consume fruits, seeds, and flowers. They consume soft leaves, which are abundant in the canopy layer, and their diet includes leaves from the figs and legumes. Their diet is low in energy, and the reason why they have low metabolic rates and rest for most of the day.
  • Activity Patterns: These monkeys are diurnal and thus active by day. The activity is more low-key than high-energy. They rest frequently in the trees, even at times for long hours without motion. Their call, particularly their distinctive "howling" type of call, is used chiefly for contact calls with other troops, territorial announcements, and a warning to other monkeys of their presence.
  • Ecological Role: Red howler monkeys, as herbivores, contribute to seed dispersal and forest plant diversity. Indirectly, they influence canopy structure by consuming various types of plants, with potential effects on plant growth and regeneration. They also reduce competition with other herbivores and primates within their range due to their slow pace and limited diet.


    • References

    Conservation International. M. Sanjayan.(2025). Red howler monkey (Alouatta seniculus). 

        http://www.conservation.org/

    Figure 2: Camacho, T. (2010). Red howler monkey (Alouatta sp.) . Retrieved 2025,.

    Figure 1: Geographic distribution of currently recognized species of howler monkeys, genus Alouatta 

        (distributions  modified from IUCN 2016. IUCN Red List of Threatened Species,

    Gómez-Posada, C., Martínez, J., Giraldo, P., & Kattan, G. H. (2007). Density, habitat use, and ranging  

        patterns of Red Howler Monkeys in a Colombian Andean forest. BioOne Complete. 

        https://bioone.org/journals/neotropical-primates/volume-14/issue-1/044.014.0102/Density-Habitat-Use-

        and-Ranging-Patterns-of-Red-Howler-Monkeys/10.1896/044.014.0102.full

    Myers, M. (2004). All the world’s primates. All The World’s Primates Home.      

        https://alltheworldsprimates.org/Home.aspx

    Rowe, N. (1992). Primate Conservation Inc. https://www.primate.org/

    WNPRC. (2021). Primate factsheets – glossary. Wisconsin National Primate Research Center.            

        https://primate.wisc.edu/primate-info-net/pin-factsheets/pin-primate-factsheets-glossary/

     

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