URL: 
http://cas.bellarmine.edu/tietjen/Research/wooly_monkey_behavior_and_vocali.htm

   <h>Wooly Monkey Behavior and Vocalizations 
_________________________________________________________________

<p>View the PowerPoint Presentation


           <h>Vocalizations & Displays in the Common Woolly Monkey

                          <h>(Lagothrix lagothricha)

                               <h>Lindsey Hughes



   <h>Abstract

             <p>Two troops of captive woolly monkeys were observed with the
   aid of an 8 mm video camera and a proprietary Palm Pilot program.  My
   research up to the present will be continued, but with modifications
   in equipment and methods of data.  The two troops differ since Troop I
   consists of a family group with four members; the breeding male Corey,
   his son Tomas and daughter Sara, and a non-breeding female named Sissi
   who is the Coreys sister.  The mother of Tomas and Sara died while
   giving birth to Sara.  Troop II consists of three unrelated males,
   with two more unrelated males who are currently in isolation to be
   introduced in the near future.  Troop I is one of only two captive
   family troops of woolly monkeys in the world; the other is located in
   London, England.

               <p>The video recordings were analyzed frame-by-frame using a
   proprietary video digitization program.  The vocalizations were
   recorded by the video camera as well and analyzed using Sound Forge to
   make sound spectrographs, or sonograms.  A programmed Palm Pilot was
   used to record the movement and behavior of both troops in order to
   make ethograms to display patterns of behavior and vocalization.

               <p>The following was anticipated:
			   <l>1. vocalizations would be
   correlated with visual displays;
   <l>2. display function would be
   identified through context;
   <l>3 individuals would be identified through
   harmonics in the sonograms;
   <l>4. the behavior and vocalizations of the
   two troops would differ; and
   <l>5. the behavioral analysis would be
   useful for maintaining and breeding captive troops.



   <h>Introduction

               <p>The common woolly monkey (Lagothrix lagothricha), also
   known as Humboldt's woolly monkey, is found only in South America in
   the Amazon River Basin of Brazil, Colombia, Ecuador, Peru, and
   Venezuela.  They range in all canopy levels of primary rainforest as
   well as gallery forests, and have been found in mountainous areas and
   cloud forests up to 3,000 meters.  The classification of the common
   woolly monkey is as follows:

   <h>Taxon

                              <h>Classification

   <l>Kingdom

   <l>Animalia

   <l>Phylum

   <l>Chordata

   <l>Class

   <l>Mammalia

   <l>Order

   <l>Primates

   <l>Suborder

   <l>Haplorrhini

   <l>Family

   <l>Cebidae

   <l>Subfamily

   <l>Atelinae

   <l>Genus

   <l>Lagothrix

   <l>Species

   <l>lagothricha


               <p>The morphology of the common woolly monkey is similar to
   that of other monkeys in the Atelinae subfamily.  The woolly monkey is
   the largest monkey in South America, with the female weight averaging
   11 pounds and the male weight averaging 15 pounds.  They have a
   prehensile tail that can support their full weight and is used for
   feeding and locomotion.  Woolly monkeys can have dark brown, pale
   brown, dark gray, pale gray, reddish-brown, or black fur.  The limbs,
   tail, and head are usually darker than the back, with the face being
   black and the palms of the hands and feet being pink.  Slight sexual
   dimorphism exists including the canines, body, and head in the males
   being longer than females.  However, the female's tail is longer than
   the male's and the female's clitoris is longer than the males' penis,
   which sometimes makes it difficult to determine the sex in the wild.

               <p>Humboldt's woolly monkey is primarily frugivorous, but
   they also feed on leaves, seeds, flowers, and some invertebrates and
   small mammals.  In captivity they have been known to prey upon birds
   that fly into their cages.  The group size for woolly monkeys averages
   10-12 group members, but much larger groups are known to exist.
   Subgroups sometimes form and travel independently from the larger
   group.  Woolly monkeys are not territorial and allow group ranges to
   overlap and have been known to forage alongside each other as well as
   other species in their family.  The woolly monkey travels through the
   forest quadrupedally using its tail as a fifth arm.  They rarely come
   down to the ground and, therefore, are known to be almost totally
   arboreal.  They even sleep 150 feet above the ground in the canopy.
   When on the ground, which is especially rare in the wild, they walk
   bipedally, using their arms and tail to balance.  The tail is
   extremely important and is always anchored to something; it is used to
   pick up objects and sometimes even allows the monkeys to rest by
   hanging from just the tail.

               <p>The social structure of the common woolly monkey is a
   multi-male-multi-female group in which a hierarchy exists between the
   males in the group.  The dominance hierarchy is determined by
   play-fighting and age.  The species' mating system is polygamous
   because each receptive female mates with every male in the group, with
   the most dominant males receiving the most copulations.  Because of
   this, the male that succeeds in passing on his genes is the one that
   releases more and better-fit sperm per session, with multiple sessions
   increasing the likelihood.  Therefore, every male mates with every
   female, but only one female is copulated with at any given time.  In
   addition to receiving the most copulations, the most dominant males
   also receive the most social grooming and are known to protect mothers
   and their infants from others in the group.  In general, adult and
   subadult males are dominant over all other members in the group.

               <p>Male woolly monkeys are philopatric, which means that the
   males stay in the group in which they were born, known as their natal
   group, while the females leave their natal group.  Female dispersion
   usually occurs between the ages of five and a half years to six years,
   the same ages that females begin to mate.  Although females begin to
   mate between those ages, they remain sterile and do not conceive until
   one to three years after they leave their natal groups.  The gestation
   period averages seven and a half months, or about 223 days, and the
   female gives birth to one young about every two to three years during
   the birthing season, which occurs between the months of August and
   December.  After birth, the infants nurse from sixteen to twenty
   months, traveling independently by six months.

               <p>Little research on woolly monkeys exists, with the
   majority of the research focused on ecology, morphology, location,
   social structure, and so on.  Research on the behavior and
   vocalizations of the common woolly monkey is almost completely
   nonexistent.  The research on woolly monkey behavior and vocalization
   that has been done was performed by M. Ramirez and published through
   the World Wildlife Fund in 1988.  His research was made into a
   "dictionary" that explained the behavior or reason behind each
   vocalization, which he spelled out using human phonetics.  He also
   explained some of the woolly monkeys' visual communication.  Although
   thorough in some respects, his research did not investigate sequences
   of behavior and vocalization or analyze each individual separately
   with respect to behavior and vocalization sequences.

   <h>Methods

               <p>My research on the common woolly monkey was conducted at
   the Louisville Zoo, one of only two places in the world that have a
   captive family troop.  After being formally introduced to the monkeys
   by the head veterinarian, I was able to begin collecting data.  Before
   starting the data collection process, I decided to spend a few weeks
   observing the two troops in order to become acquainted with the
   individuals.  During the three weeks of strict observation, I took
   notice of each behavior and began compiling a list of the observed
   behaviors.  This list is located in the results and discussion
   section.  I also realized that not only could I tell the monkeys apart
   visually, but vocally as well.  After becoming familiar with the
   behaviors (displays) and vocalizations of the monkeys, I began
   collecting data.

               <p>The data collection consisted of a variety of methods
   including the use of an 8 mm video camera to record behaviors, a mini
   disk recorder to record the vocalizations, and a proprietary Palm
   Pilot program to record the movement and behavior of each individual
   in the two troops as well as the overall behavior of each troop.  At
   first, I videotaped the woolly monkeys individually.  This method was
   not effective because the behavior of the other woolly monkeys could
   not be seen and the monkeys move extremely fast and it is difficult to
   follow them around the cage.  I then tried to videotape sections of
   the cage, but that did not work well either because I could not
   differentiate between the monkeys because of the cameras bad
   resolution.  After four hours of recording over one month, I realized
   that I needed a much better video camera in order to continue with the
   research.  For my future research I will have a video camera with
   superior resolution.  The video recordings that I had were used to
   learn and practice the digitization process.  The recordings were
   digitized and transferred to compact disk for later analysis.  The
   digitized version of the video recordings could be analyzed at 1/10 of
   a second, with the potential advantages including the ability to
   record the behavior at set intervals, allowing the viewer to record
   the behavior of all the monkeys in view.

               <p>The mini disk recorder was used in conjunction with the
   video camera.  I experienced multiple difficulties and problems with
   the mini disk recorder that eventually led me to discontinue using it
   in this project.  This will be discussed further in the results and
   discussion section.  Because I did not have any vocalizations
   recorded, I decided to use the sound from the video recordings for my
   vocalization analysis.  Sound Forge, a computer program used for the
   sound analysis, enabled me to make sound spectrographs, or sonograms,
   on the woolly monkey vocalizations.  In order to analyze just the
   woolly monkey vocalizations and not all of the background noise,
   adjustment was required. With Sound Forge, I was able to delete all of
   the outside and background noise that included crickets, birds,
   trains, human voices, and so on.

               <p>The proprietary Palm Pilot program used for recording the
   behaviors was called Pen Recorder and the program used to analyze the
   recordings was called Pen Reviewer.  Below are diagrams of Pen
   Recorder, Pen Reviewer, and View Data.

   <p>When using Pen Recorder, I had to designate letters of the alphabet to
   the observed behaviors.  Once I started Pen Recorder, I wrote the
   letter of every behavior that I observed an individual doing until
   they went inside or went to sleep.  This method was difficult because
   it was impossible to keep up with the behaviors while having to
   remember which letter went with which behavior as well as write the
   letter and then keep going.  The collected data was viewed in Pen
   Reviewer under View Data, displayed above, and then analyzed in the
   form of a graph, time line, and matrix, displayed below.

   <p>After using this technique for a while, I decided to change my method
   of recording because of the above stated reason as well as the fact
   that certain monkeys were more active than the others and I had to
   start and stop recording for the different individuals, which does not
   heed good results for analysis.  For my further research, I will be
   using a new method of recording behaviors.  Instead of using the
   proprietary Palm Pilot program, I will be using a tablet PC with a
   voice recognition program so I can just speak each behavior as it
   occurs.

   <h>Results & Discussion

               <p>The individual woolly monkeys of Troop I each have
   extremely different personalities, rank, age, relationships, etc.  The
   family troop consists of four related individuals:


   <h>Name

                                <h>Birth Date

                                    <h>Age

   <l>Corey

   <l>11/13/91

   <l>11 years

   <l>Sissi

   <l>09/29/95

   <l>7 years & 2 months

   <l>Tomas

   <l>12/01/98

   <l>3 years & 11 months

   <l>Sara

   <l>12/07/00

   <l>1 year & 11 months

          <h>Corey                              <h>Sissi
        <h>Sara                           <h>Tomas


               <p>Corey is the dominant breeding male and is father to both
   Sara and Tomas.  Sissi is Corey's sister and is the dominant
   non-breeding female.  Sissi has never had any offspring and is
   considered sterile.  The position of the second most dominant member
   of the troop is currently being fought over between Sissi and Tomas.
   Because Tomas is a subadult male and Sissi is an adult female, he and
   Sissi fight over everything, from food to where to sleep.  Thomas and
   Sara are siblings and fight and play in ways similar to human
   siblings, but still show affection quite often, grooming each other
   and resting next to each other.

               <p>Tomas and his father Corey appear to have the closest
   relationship within the group.  Tomas follows Corey around, mimicking
   certain behaviors.  When Tomas and Sara are resting together or
   grooming each other, Corey generally joins them.  Strange to human
   viewers, the family troop members are sexual with each other,
   especially Corey and Tomas and Corey and Sara.  Sexuality between
   family members is surprisingly common in the primate world.  According
   to primate research, it is quite normal for a father and son to feel
   on each other's genitals and have erections when around one another.
   These behaviors are considered greetings and are meant to establish
   friendly contact, usually occurring between adult males and juveniles
   of both sexes.  During my observations, I noticed that Corey and Sissi
   rarely interact, while the same is true for Sara and Sissi.

               <p>The monkeys in the family troop have differing
   personalities, with Corey as the alpha male.  He is the largest
   monkey, with huge canines and constant eye movement that indicates a
   neurological disorder, though not apparent in any other way.  Corey
   never plays and is always pacing the cage, eating, grooming himself or
   others, staring at outside disturbances, or resting.  Only after about
   a month of observation Corey appeared not to consider me an outside
   threat anymore, showing behaviors indicating a friendly greeting and
   then calming down other group members through appeasement behaviors.
   This meant that I could now observe their behavior undisturbed by
   outsiders.  Tomas is more of a loner for the majority of the time; shy
   toward outsiders, he never makes eye contact with me, which is unlike
   all the others in the group.  When not off by himself, Tomas is
   playing or play fighting with Sara, fighting with Sissi, or grooming
   or resting with Corey and/or Sara.

    <h>Corey staring      <h>Tomas hiding    <h>Sissi & Tomas    <h>Sissi
   walking         <h>Sara eating

                                                                 <h>fighting


               <p>Sissi is the most unsocial member of the group, only
   interacting with the others when fighting with Tomas.  She is,
   however, active toward me, cage shaking, which is a sign that she
   feels threatened, and intense staring sessions at me, most likely
   indicating that she does not approve of my presence.  When not
   interacting with Tomas or me, Sissi rests high up in the top of the
   cage, far away from everything and everyone else.  Sara on the other
   hand is the most active and social member of the group.  Sara is
   always doing something, whether watching me, playing with Tomas,
   resting with Corey and/or Tomas, eating, playing by herself with toys,
   or just running around bipedally on the cage floor.  The youngest,
   most curious and loving of the group, she is the one that has tried to
   make contact with me the most and is the most affectionate toward
   others.

               <p>Below is a table listing the observed behaviors, their
   description, and the individuals in which the behaviors were observed.

   <h>Behavior

                                <h>Description

              <h>Individuals In Which The Behavior Was Observed

   <l>Eat

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Play

   <l>Self explanatory; includes biting, running, climbing, rolling around,
   etc.

   <l>Sara, Tomas

   <l>Chestrub

   <l>Rub object against chest to scent mark; usually only done by males

   <l>Corey, Tomas, Sara

   <l>Swing

   <l>Self explanatory; on ropes or around the cage

   <l>Corey, Sissi, Sara, Tomas

   <l>Walk Quadrapedally

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Fight

   <l>Self explanatory

   <l>Sissi, Sara, Tomas

   <l>Groom

   <l>Each other or themselves

   <l>Corey, Sara, Tomas

   <l>Walk Bipedally

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Teeth Chatter

   <l>Dominant male moves jaws up and down rapidly, chattering his teeth;
   threat display or sexual arousal display

   <l>Corey

   <l>Jump

   <l>Self explanatory; on floor, up to cage or rope, etc.

   <l>Corey, Sissi, Sara, Tomas

   <l>Climb cage

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Climb Rope

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Cage Shake

   <l>Use all four limbs to shake the cage; threat display

   <l>Corey, Sissi, Sara

   <l>Rub

   <l>Use hands to rub on each others bodies; brings appeasement and
   strengthens close relationships

   <l>Corey, Sara, Tomas

   <l>Bite

   <l>Self explanatory

   <l>Sissi, Sara, Tomas

   <l>Grasp With Tail

   <l>Use 5^th limb to hold on to objects or pick up objects

   <l>Corey, Sissi, Sara, Tomas

   <l>Stare

   <l>Self explanatory

   <l>Corey, Sissi, Sara

   <l>Hump

   <l>Self explanatory

   <l>Corey, Tomas

   <l>Copulation Attempt

   <l>Attempt to copulate with another individual; practice for actual
   copulation; occurs between males and females and between males

   <l>Corey, Tomas, Sara

   <l>Run

   <l>Self explanatory

   <l>Sissi, Sara, Tomas

   <l>Yawn

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Lick

   <l>Themselves, each other, or various objects including the floor and the
   cage

   <l>Corey, Sissi, Sara, Tomas

   <l>Masturbate

   <l>Self explanatory

   <l>Corey, Tomas

   <l>Feel On Genitals

   <l>Feel on own or another individuals genitals; display of friendship and
   is thought to bring appeasement

   <l>Corey, Tomas

   <l>Reach For Me

   <l>Self explanatory; reach out of cage to try to touch me

   <l>Corey, Sara

   <l>Rest

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Sneeze

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Drink

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas

   <l>Scratch

   <l>Self explanatory; usually themselves

   <l>Corey, Sissi, Sara, Tomas

   <l>Hang

   <l>Upside-down with tail grasping object and supporting entire body

   <l>Corey, Sissi, Sara, Tomas

   <l>Reach Out Of Cage

   <l>Self explanatory; usually to get leaves, sticks, or other food dropped
   outside of the cage

   <l>Corey, Sissi, Sara, Tomas

   <l>Sit

   <l>Self explanatory

   <l>Corey, Sissi, Sara, Tomas


   <p>In addition to using the video recording of the woolly monkeys for
   behavioral analysis, it was also used for sound analysis.  I used a
   computer program called Sound Forge, which enabled me to make sound
   spectrographs, or sonograms, of the woolly monkey vocalizations. In
   order to analyze just the woolly monkey vocalizations and not all of
   the background noise, adjustment was required.  Using Sound Forge
   enabled me to delete all of the outside and background noise including
   crickets, birds, trains, human voices, and so on.  I was able to
   produce several sonograms from the data collected by listening to the
   sounds while watching the screen and marking where I heard common
   sounds of the woolly monkey.  These common sounds included shrieks,
   squeaks, and grunts.

   <p>I then performed a spectrum analysis, an option in Sound Forge, in
   order to view the vocalizations in the form of a sound spectrograph.
   Although this analysis is not yet complete, it will be continued in
   the future.  After more spectrographs are made and analyzed, I will be
   able to differentiate between individuals just by looking at their
   sonograms because it is my hypothesis that each individual produces
   different sound spectrographs although they make the same
   vocalizations.  The human ear might not be able to differentiate
   between individuals when they are making the same sounds as others so
   this data will be useful in further vocalization research in woolly
   monkey populations.

   <p>The sound spectrograph below is of a squeak.




   <p>The next sound spectrograph is of a screech.



               <p>The last sound spectrograph is of a grunt.




   <p>For my further research, I will be using a new method to record
   behaviors.  Instead of using the proprietary Palm Pilot program, I
   will be using a tablet PC with a voice recognition program so I can
   just speak each behavior as it occurs.  The program is called Dragon
   records what I say and analyzes the data in a similar manner to that
   of the proprietary Palm Pilot program.  I will also be using an Elura
   40 digital video camcorder, which has superior resolution and sound
   quality combined with the ability to take digital photographs.  The
   camera also has a steadier that eliminates most of the shakiness from
   holding the camera.

   <p>The observation of Troop II will begin when the two new unrelated male
   monkeys are introduced to Monkey Island.  I will continue recording
   more vocalizations and perform more in depth analysis using Sound
   Forge.  This research will be helpful in teaching zoo personnel and
   others interested in woolly monkeys about their behaviors and
   vocalizations, as well as being useful for maintaining and breeding
   captive troops.
     _________________________________________________________________

