Zoo LabThe Observations of Two Different Primates

Biological Anthropology 0103Gabby Bryant

University of Maryland, College Park

Abstract

For this Zoo Lab, we were asked to visit the Smithsonian Zoo in Washington, D.C.

and observe Golden Lion Tamarin and another primate of our choice for thirty minutes

each. This would be used to compare their social behavior and locomotion to hypotheses

that we should have come up with before our observations. As my second primate, I chose

the Black Howler Monkey, which is related to the Golden Lion Tamarin, as they are both

New World Monkeys. During the observation of both of these primates, the Tamarin

displayed the most locomotion and movement, while the Black Howler Monkeys displayed

the most social behavior between the female, male, and their newborn baby. Although they

are very similar genetically, both species acted very differently in their environments and

toward one another, as well as with the humans that were observing them behind glass.

Introduction

The primate world is vast and diverse ranging from tiny marmosets in the forests of

Brazil to the large and proud gorillas in Africa. Each and every primate is unique, and yet so

closely related to other primates. As a whole, primates display three basic traits that link

them together: arboreal adaptation, dietary plasticity, and parental investment; however,

their behavior and morphologies vary from species to species, from large and imposing to

small and fast. For this lab, along with the Golden Lion Tamarin that we were told to study,

I chose the Black Howler Monkey. From the little I knew about both species, I drew some

questions related to their individual social behavior and locomotion. For the Golden Lion

Tamarin, I questioned if they would groom each other, and also if they would ever leave

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their branch perches and walk on the ground of their enclosure. As for the Black Howler

Monkeys, I asked questions when I first saw them, would the male and the female be

affectionate to one another, and if they would use their prehensile tails to swing among the

braches in their enclosure.

The Linnaean Classification system is a system that breaks all living things down

into categories or into “various levels of hierarchical classification”(Larsen, Clark, Spencer):

Kingdom, Subkingdom, Phylum, Subphylum, Superclass, Class, Subclass, Order, Suborder,

Superfamily, Family, Genus, Species, and Subspecies. Using this classification system,

Golden Lion Tamarin and Black Howler Monkeys are actually quite closely related. Alouatta

caraya is the Black Howler Monkey and Leontopithecus rosalia is the Golden Lion Tamarin.

Figure 1 displays the Linnaean Classification of both species of primate. (Eskeleton)

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As shown in the figure above, both the Golden Lion Tamarin and the Black Howler

Monkey share the same Superfamily, however their ancestries split off at the Family level.

They are both part of the Suborder Anthropoidea and the Infraorder Platyrrhini, which

means that they are both New World Monkeys; they are predominantly found in North and

South America.

Both species of primate have very interesting morphological features that vary. The

Golden Lion Tamarin are typically quite small, between six and ten inches long, with a ten

to sixteen inch tail that is non-prehensile, meaning that they cannot use it for swinging or

as an important fifth limb. Their name comes from their color and hair pattern: golden-red

in color and in a mane around a hairless face like a lion (Denver Zoo). Their dental pattern

is 2.1.3.2, which is different than other New World Monkeys and they have a small round

cranium. They have claws instead of nails and their “thumbs are not fully opposable and

their hallux (big toe) is located back from the other digits (similar to a bird’s big toe) and

retained its flat nail” (Zoo Atlanta). This allows the Golden Lion Tamarin to easily jump

from branch to branch and climb tree limbs. They are mostly completely arboreal. Also, like

most other primates, their scapulas are long and narrow.

Black Howler Monkeys, on the other hand, “are the largest monkey in Latin

American rainforests; they grow to be about two to four feet tall and weigh from eight to

twenty-two pounds. They have big necks and lower jaws, where their super-sized vocal

cords are housed” (Honolulu Zoo). Along with their huge vocal cords, they also have a

larger hyoid and angled jaw that allows them to “howl” quite loudly. This howling is used to

defend the Howler Monkey’s territory. Black Howler Monkeys are also not always black;

only the male is black, while the female is a lighter brown color, however they both have

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hairless faces. According to some experts, females are believed to be a brown color as a

survival strategy because it allows them to blend in with colors in the forest (Honolulu

Zoo). Black Howler Monkeys also have a useful prehensile tail. They are also sexually

dimorphic by size and by the size of their canines and have shearing crests that are useful

for their mainly foliage-based diet (Eskeletons).

Both of these species are native to South American and Central American rainforests

and both are arboreal. Golden Lion Tamarin prefer to stay in swampy humid areas in the

sub-canopy of the rainforest where they are protected from flying predators and are closer

to their food sources (Zoo Atlanta). Black Howler Monkeys prefer the larger branches

higher up in the rainforest where they walk from tree to tree in search of fresh, new leaves,

which serves as food (Rainforest Alliance). Both species are also diurnal.

For my trip to the zoo, I have made two hypotheses for both species in relation to

their locomotion and social behavior:

-Golden Lion Tamarin Social Behavior: I hypothesize that two monkeys will groom

one another during my visit.

-Golden Lion Tamarin Locomotion: I hypothesize that the monkey I am observing

will not walk on the ground of its enclose at all.

-Black Howler Monkey Social Behavior (This hypothesize was formulized after I had

been introduced to the enclosure at the zoo): I hypothesize that the male and female

monkeys will be affectionate to one another.

-Black Howler Monkey Locomotion: I hypothesize that the monkey will swing from

one branch to another using its prehensile tail.

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Materials and Methods

I planned to go to the zoo on Monday, April 2nd sometime in the early afternoon.

After a long and arduous metro ride, I finally made it to the National Zoo. I had brought

with me my lab report documents, a couple pencils and pens, and a camera to record the

primates I would be observing. Since I had been to the zoo recently, I knew where to find

the Golden Lion Tamarin, but still was not sure about which other primate I would observe.

I decided to walk around to the outdoor Gorilla enclosure, which was empty, to my dismay.

I thought that observing the Golden Lion Tamarin would be appropriate at that time, while

I was still deciding on the other primate. I walked back to the Small Mammal House and

waited in line as thralls of children in strollers crowded the entry. I had forgotten it was

Spring Break for students in Montgomery County, if not others. As I entered the Small

Mammal House a few minutes later, I quickly saw the first Golden Lion Tamarin enclosure

directly in front of me, which housed two Golden Lion Tamarin and an Elephant Shrew. I

handed my phone to the friend I had come with and asked him to start the stopwatch and

tell me when each minute had passed by. During the thirty minutes at the Golden Lion

Tamarin enclosure, I wrote notes each minute, took a few picture, and was jostled around

by other interested zoo-goers.

After the allotted thirty minutes had expired, I thought it would be a good idea to

continue through the Small Mammal House and explore the other species on display. I

stopped briefly at the Black Howler Monkey enclosure and was pleasantly surprised at

seeing a tiny baby attached to the stomach of the female. I was still not sure about

observing them for thirty minutes because I though observing gorillas would be more

interesting, but after about five minutes of ooing-and-ahhing at this adorable baby and its

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family, I decided to stay and time myself. Like the previous enclose, I took notes every

minute and a few pictures. After finishing with the Black Howler Monkeys, I had had

enough with the thralls of tourists and decided to head back to the metro.

Results

I will preface my results with this picture of me, which was a very embarrassing

picture to take, as I was in line with about ten five-year-olds and their parents:

Golden Lion Tamarin

The Golden Lion Tamarin that I decided to observe was in an enclosure with

another Golden Lion Tamarin and an Elephant Shrew. I believe that the Tamarin that I was

observing was a male and so was the other Tamarin. I will refer to the Tamarin I was

observing as Alpha and the other one as Omega. As I began observing Alpha, he was sitting

like a dog on a branch, simply observing everything around him with quick, jerking head

movements, but he was not paying any attention to Omega. After two minutes, Alpha began

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running up the branch he had been sitting on as Omega seemed to be yelling at him with a

squeaky sound. Alpha was running and jumping around the entire enclosure until he saw

Omega run into their “private hole” in the wall, and proceeded to follow him. When Alpha

exited approximately a minute later, he was holding a grape with one hand while still

walking along on the branches. He then sat on a branch and ate the grape piece by piece

while still ignoring Omega for about three minutes. After seemingly finishing the grape, he

jumped (again with one hand still on part of the remaining grape) to another branch, at

which time the piece of grape fell on the ground. He then retreated back into his hole

behind Omega. A minute later, he came out and quickly ran down a few branches until he

reached the ground where his grape had fallen. He picked up the grape skin, ate it, then

climbed up the metal cage material at the back of the enclosure until he made it to another

branch. For the next six minutes, Alpha jumps around some branches and paused, and then

jumped around again and perched. He seems to have zero interaction with Omega, finding

sniffing branches and stretching more interesting. He then retreated into his hole for

another three minutes. While he is in his hole, an arm reached out from a door below the

hole and threw small live worms into the enclosure. Omega immediately came out and

started picking up the worms from a log on the ground, as did (so it seemed) the elephant

shrew. Alpha slowly came out of the hole and proceeded to urinate off of a branch, then

wandered along a few branches before making his way down to the worm-covered log. He

took a few worms, then retreated into the branches, then came back down and tried to take

a few more. Alpha and Omega had no interaction. Out of nowhere, Omega attacked the

Elephant Shrew, which had been very close to the log, and everyone jumped around the

enclosure for a few seconds. Alpha retreated into the hole. He peaked his head out a few

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time, came out quickly a few minutes later while chewing on something, and then retreated

again.

Black Howler Monkey

I decided to observe the female Black Howler Monkey who’s name, according to the

Smithsonian website, is Chula. The male in the enclosure’s name is Pele, and together they

have a baby who was born on March 22nd (sex unknown) (National Zoo). I first observed

the Chula sitting on a high, thick tree limb with the baby attached to her underside while

Pele tried to get her attention by nudging her and reaching for her. She kept turning her

back on him. Pele them seemed to start humping her from behind. After about a minute,

Chula started walking around the limbs while Pele continued to follow her and nudge her.

If he was behind her, he would try to reach his hand around toward the baby. She

continued walking around for a few minutes while Pele followed her. As they both walked,

Alpha and Omega eating from the tree trunk on the ground with the elephant shrew to the side Alpha perched on a branch

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they would use their tails sometimes to wrap around passing branches. Eventually, he

started walking away and she followed him and they both sat underneath a heat lamp.

After a minute, Pele retreated into his hole and Chula followed him. She came out again as

Pele followed her and they went back up to her original tree branch. For the next couple

minutes, Chula walked around slowly while Pele continued to follow her and reach around

her front toward the baby. She eventually jumped around Pele and perched on top of a high

limb. Pele sat on a lower branch as she watched him watch us (the humans). Pele then

reached out and balanced his arms on the glass of the enclosure as his legs were still on a

limb and balanced there for a few seconds watching everyone. Meanwhile, Chula wrapped

her tail around a smaller branch while she sat and started scratching it and then putting

her fingers, near her nose. She then did the same thing to her back and her toes, and then

her genital area. Pele came back up to her and Chula made a loud sound at him. She then lay

down as Pele tried to nuzzle her. Eventually she ended up sitting with her arms and legs

wrapped around the baby as Pele lay next to her and they both went to sleep. Every few

minutes she would open her eyes and look around, but neither of them moved for the

remainder of the time.

Discussion

I was surprised by both of the species that I observed. I had hypothesized that the

Golden Lion Tamarin would groom one another because I believe that they would be more

social than they seemed, and that they would not go on the ground at all, which they did.

As I was observing Alpha, I noticed that he moved around a lot less than Omega and that he

seemed intimidated by Omega especially when there was food to be had. For the most part,

Alpha and Omega completely ignored each other and never once touched each other.

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Perhaps because they were both males (I am assuming), they had no purpose to interact

with each other. As for locomotion, I believed that Alpha would stay up in the branches and

move around a lot, however, because there was food on the ground, Alpha left the branch

and went to find it. I also found it very interesting that neither Alpha nor Omega really

cared about the elephant shrew until it came near their food.

The Black Howler Monkeys were, by far, the most interesting primate to observe.

Their behavior was fascinating and so was their locomotion. The entire time I was

observing Chula and Pele, Chula was trying to ignore and walk away from Pele as he

continuously followed her around. What was interesting was the speed at which they

moved: each moved very slowly. He seemed to want to take care of the baby or take part in

keeping it safe. Not only did Pele seem to want to take care of the baby, he also seemed to

Chula with her tail wrapped around a branch, baby clinging onto her underside

Chula and Pele sitting together under the heat lamp with the baby clinging to Chula

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want attention from Chula, which she was completely unwilling to give. Chula was not

affectionate to Pele in the least, however Pele did seem to nuzzle her and appreciate her a

little. As I watched Chula and Pele’s interactions, it reminded me of two young people in a

social situation where the female does not want to talk to the male, but the male is trying

his hardest to get her attention and gain her affection. As for using their prehensile tails,

neither Pele nor Chula swung from their tails, probably because the braches/limbs in their

enclosure were much too thick for a tail to wrap around. Chula did, however, wrap her tail

around a small branch when she was scratching herself, showing that it was capable of that

function. Having the baby in this enclosure definitely increased the behavioral observations

that could be made. Chula never seemed to really pay any attention to the baby that was

attached to her underside the entire time-at one point it even looked as though the baby

was feeding-until right at the end of the thirty minutes when she wrapped her entire body

around the baby as if to protect it and keep it warm as they slept.

Overall Locomotion

Climbing

Overall Social Interaction

Touch Between Species

Interaction With Observers

0 1 2 3 4 5 6

Golden Lion TamarinBlack Howler Monkey

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Figure 2 Displays the time spent for each primate between social behavior and locomotion,

out of 6 points.

As shown in the figure above, the Golden Lion Tamarin and Black Howler Monkeys

had much different outcomes between the time they spent interacting with others and the

time they spent moving around. It is clear that the Golden Lion Tamarin spent the most

time moving around, while the Black Howler Monkeys spent the most time interacting with

not only each other, but with the observers of their enclosure, i.e. the humans.

Conclusion

Overall this lab with very interesting and enlightening. Not only were two primates

researched and compared, they were also observed in person to better understand their

social behavior and their locomotion. Had these two species been in their natural habitats

and not in small enclosures in a zoo, they may have acted differently, but their main

characteristics were displayed very well. The Golden Lion Tamarin moved around a lot and

very quickly while searching for food, and Black Howler Monkeys moved around more

slowly while sometimes using their prehensile tails for support. In the end, the baby Black

Howler Monkeys stole my attention and created a very interesting environment to observe.

Had it not been there, my understanding and observations of the Black Howler Monkeys

would have probably been different. In the end, the actions of both primates exemplified

many actions that humans do every single day, just showing how close we as humans are to

our distant relatives, these other primates.

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Bibliography

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Honolulu Zoo. "Black Howler Monkey." Association of Zoos and Aquariums, 2008.

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