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Clay Chastain
Dr. Hamilton, ANTH 2310-1
The Zoo Project: Nonhuman Primate Research
7 November 2006
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Background Information
In the world, a variety of primate species exist. Each species a unique function in
the wild and differs, sometimes greatly, from another primate species. Two species that
will be analyzed here are the Wolf’s Guenon (Cercopithecus wolfi), an Old World
monkey, and the Black-handed Spider Monkey (Ateles geoffroyi), a New World monkey.
While both are very similar at first glance, each monkey is surprisingly different. One key
feature to note that causes such a wide variety in these species is their physical location.
The separation of a common ancestor through continental drift caused the Wolf’s guenon
to evolve in Africa, specifically throughout the Congo territories and Uganda (Wolf’s
Monkey Website) (Figure 7). However, the black-handed spider monkey evolved
independently throughout the tropical regions of Central and South America (Blackhanded Spider Monkey Website) (Figure 3). Because of this separation in habitat, there
are a range of differences between these monkeys; still, there is a degree of similarity on
many aspects of these monkies. The Black-handed Spider monkeys are “fruigivorous,
preferring a diet of 90% fruit and seeds”; however, they also eat some insects on
occasion. They eat a great deal throughout the day, as well as eating while suspended in
the air on a tree branch or manmade object. They do not, however, “pick fruit and carry it
to another location to be eaten” later on. In zoos, they are fed from a mixture of
vegetables, such as celery, and fruits, such as bananas (Spider Monkey Website). The
Wolf’s guenon has a moderately similar diet which consists of “[f]ruit, leaves, flowers,
nectar and insects”. In terms of reproduction, each Wolf’s guenon will have a gestation
period of 160 to 170 days, give birth to generally one child, and each child will usually
survive up to 26 years in all (Wolf’s Monkey Website). Slightly different, the black-
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handed spider monkey has a gestation period of 226 to 232 days. The female is sexually
active at four to five years old, while the male is sexually mature at five years. Any baby
that is produced will be solid black (Figure 1) and will be dependent on the mother’s milk
for around two years. (Spider Monkey Website). Socially, little is “known of [the Wolf’s
guenon]'s social structure, however comparisons with other guenon species indicate that
the Wolf’s guenon probably live in small family groups consisting of a parental pair and
their offspring” (Wolf’s Monkey Website). Fortunately, more is known about the blackhanded spider monkey; they travel in groups of four to thirty-five individuals, usually
with twice as many males as females (Wildfacts Website). As well, the females have a
more active role as a leader in the group as do the males. In terms of conservation, the
black-handed spider monkey is not endangered and is listed as “low risk” by the IUCN
(Spider Monkey Website). Similarly, the Wolf’s guenon is also not incredibly
endangered. Despite this, due to habitat loss, their numbers have suffered a “considerable
reduction” (Wolf’s Monkey Website).
Zoo Setting
The setting that this research took place was at the San Antonio Zoo on Saturday,
October 21, 2006. The temperature was a temperate 76 F with a generally clear sky and
bright sun at the start of the research at 12:40 PM. Both of the primate species are located
in relatively small enclosures designed to maximize space; they seem to be focused on
the vertical aspect instead of the horizontal. As such, they are both taller than wider,
which is most likely a simulation of arboreal life to some extent. While a portion of the
habitats are constructed of wooden branches, much of the objects placed inside the
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enclosures were manmade objects (such as a hanging plastic bucket placed in the Wolf’s
guenons’ cage). The habitats are, of course, a very sparse simulation of their real life
counterparts. There are no dense areas of foliage and the enclosures did not have natural
surfaces on any side. As well, they are very small for the amount of animals contained
within each. Overall, the habitats are an incredibly restricted and limited version of a
tropical forest. The wolf’s guenon group consisted of three individuals, all of which
appeared to be adult females. The black-handed spider monkey had an indeterminable
amount of individuals; however, three monkeys were clearly visible during the
observation period. All of these monkeys appeared to be adults and only one was a male.
One of the females was slightly smaller, which could indicate that she is younger than the
others. Comparatively, the group of Wolf’s guenons did not reflect a family structure
(however, it is still possible for the group to have been a family). As well, the group of
black-handed spider monkeys could have been a small family or troop, but because of
their lack of activity, it was not easily distinguishable. In the wild, the monkeys would
probably be a much closer family unit, or in the case of the black-handed spider monkey,
a larger, structured troop of monkeys led by a female.
Physical Characteristics
Both primate species have a tail. Despite this similarity, both use them differently.
The black-handed spider monkey relies on its tail much more as it is clearly prehensile.
Its tail is used to hang from branches and other objects, to grab food and other monkeys,
and to balance the when needed (such as when walking on a rope). The Wolf’s guenon
uses its tail in a more basic way. Because its tail is not prehensile, it is used almost
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exclusively for balance. Yet, in some situations when the monkeys became angered at
each other and started to fight, it was stuck up in the air as a way of intimidating the other
party. Telling sexes apart proved very difficult, especially on the Wolf’s Guenons. There
is very little dimorphism that can be seen from afar in either of these species. Fortunately,
a black-handed spider monkey was lying at an angle in which its underside was slightly
visible, leading me to assume that one is indeed a male. Coloration wise, there were no
young individuals present to make a clear observation of the differences between the age
groups, however, my research shows that younger black-handed spider monkeys are
black-bodied as well (Figure 1). Unfortunately, seeing the teeth of these animals is
incredibly difficult; the case of the Wolf’s Guenon which was always eating, it covered
its face with its hand while it broke open peanuts and stuffed newspaper in its mouth.
Similarly, the black-handed spider monkey never was positioned close enough or at the
right angle to see its canines. However, each species was definitely unique in its physical
appearance. The Wolf’s guenons have a large white underside while having a pointed
white facial ridge; much of their coat is a brownish orange (Figure 5, 6). The blackhanded spider monkey has a more typical brownish monkey color (Figure 2), but the
main point of interest is its black hands (Figure 3).
Locomotor Behavior
Overall, the Wolf’s guenons and the black-handed spider monkey enjoyed staying in an
arboreal location. However, many differences persist between the species. The Wolf’s
guenon’s, for example, seem to be mixed between sitting in trees and climbing to higher
branches while also exhibiting strong patterns of playing and walking on the ground. This
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monkey species seems to be well suited to both hopping around on the ground using its
hind legs or leaping (also with its hind legs) in the branch areas of the enclosure. The
Wolf’s guenons often sat upright in a bipedal position while resting on a branch similar to
that of a possible pose of a human (sitting upright with its knees close to its head), but
they only appeared to move in a quadrupedal motion. They also tended to lay down on a
branch just as much as they sat up on them; especially when they are resting, lying down
is the major position a monkey will be in. When moving from branch to branch, there did
not appear to be any swinging of the arms to indicate brachiation. Also of note, the
Wolf’s guenons seemed to walk on their palms with a mild curve in their hands, but after
starting to run across branches, they express a more cupped hand approach to hanging on.
These monkeys also handle objects in an interesting way: they grab an object with their
fingers by using their thumb extensively and then break it apart with either their mouth or
their other hand. It will then use its teeth to break open an object by rotating it in its
mouth. They generally tended to use their hands instead of their legs, although their feet
often were used to pass goods to their hands, however, the handedness was indeterminate.
On the other hand, the black-handed spider monkey is a different story. Largely due to
their prehensile tail, these monkeys have a distinct pattern of locomotion. The monkeys
tended to be almost exclusively arboreal, hardly finding a reason to explore the ground.
Because of their tree-fairing nature, they were able to jump in large leaps from branch to
branch. Like the Wolf’s guenon, though, the black-handed spider monkey was a
quadrupedal creature, using its back legs for the majority of its power. Unlike them, the
black-handed spider monkey uses its prehensile tail (and lack of thumb) to move in a
different manner. The monkeys were not observed walking in a bipedal position, but like
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the Wolf’s guenon, it occasionally sat in a more upright position, similar to humans
which bend their knees close to their face. The monkey did seem to use both its front and
hind legs almost equally, except when eating food, which it did through its front legs a
majority of the time. Despite the fact that these monkeys do not have prehensile hands
due to the lack of a thumb, they still seem very capable of grabbing and holding objects.
Unfortunately, the angle was too obscure to properly see the way the monkeys ate with
their hands. Because the black-handed spider monkeys were almost always in the
branches, they used a strong grasping hand form, much like a cup; again, there was no
obvious preference in left and right hands, but these monkeys did use their hind legs
considerably more than the Wolf’s guenons. Although these monkeys rested quite a bit
during the day, they always seemed ready to jump, never relaxing their grip on the tree
area.
Social Behavior
Both of the monkey species had a very complex social system. Even though the
black-handed spider monkeys were not incredibly active during the research period, their
basic community was well expressed except for sexes which were partly speculation
based on behavior and partial visible evidence. They showed a definite interest in each
other’s food collection and eating, but often did not engage another member of the
community unless they had already been playing prior to whereas the Wolf’s guenon
strongly interacted with each and every object to the extent of causing fights between the
monkeys. After a man threw a cigarette butt into the general area of the enclosure, the
Wolf’s guenons both tried to reach it with an intense interest, making loud noises while
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failing. When one finally did get it, this inspired a chasing game of sorts. The winner
monkey started to make loud noises at the loser, and the loser responded by chasing the
winner up to the top of the cage. Yet, this situation escalated from a simple play tactic to
full-on fight between the monkeys when one tackled another onto the ground. However,
the monkeys later forgave each other through what appears to be a hug. They then
collectively ripped the cigarette to pieces later without any agitation from either party.
The Wolf’s guenons exhibited a somewhat strong sense of companionship to the other
individuals in the enclosure despite previous negative encounters. The black-handed
spider monkeys were generally less active than the Wolf’s guenons. While they did both
chase and play at some points, they were very limited and ended with one either eating
food or going to sleep on a branch for several minutes. These monkeys made more noise
overall than the Wolf’s guenons, but they did not always seem too attentive to the
situation and generally ignored the other. Because the black-handed spider monkeys were
so inactive, it is difficult to say much about the dominance or other aspects of their social
structure.
Comparisons and Evolutionary Interpretations
Overall, the two species of monkeys are very similar in terms of physical structure
and many behavioral traits. However, these monkey species are separated by their
taxonomic families, instead on relating on the level of the primate order.
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References Cited
Malloy, Betsy. Online image. 2006. Wolf’s Guenon. About.com. 28 Oct. 2006.
<http://gocalifornia.about.com/bl_sdzphoto_trts.htm>.
Online image. Black Handed Spider Monkey. Central Florida Zoological Park. 28 Oct.
2006. <http://www.centralfloridazoo.org/animals/Blackhanded_spider_monkey.htm>.
Online image. Central & South American Lodgings. Bestlodging.com. 28 Oct. 2006.
<http://www.bestlodging.com/central-south-america/index.shtml>.
Online image. Facts About The Continent Africa. Abbott-Infotech. 28 Oct. 2006.
<http://www.abbottinfotech.co.za/facts%20about%20the%20continent%20of%20africa.html>.
Online image. Spider Monkey. Honolulu Zoo. 28 Oct. 2006.
<http://www.honoluluzoo.org/spider_monkey.htm>.
Online image. Wildfacts – Black-handed Spider Monkey. BBC – Science & Nature. 28
Oct. 2006. < http://www.bbc.co.uk/nature/wildfacts/factfiles/310.shtml>.
Online image. Wolf’s Monkey. Congo Gorilla Forest – Bronx Zoo. 28 Oct. 2006.
<http://www.congogorillaforest.com/congo-meet-wolfsmonkey>.
“Wolf’s Monkey.” Congo Gorilla Forest – Bronx Zoo. 28 Oct. 2006.
<http://www.congogorillaforest.com/congo-meet-wolfsmonkey>.
“Black-handed Spider Monkey.” Central Florida Zoological Park. 28 Oct. 2006.
<http://www.centralfloridazoo.org/animals/Black-handed_spider_monkey.htm>.
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“Spider Monkey.” Honolulu Zoo. 28 Oct. 2006.
<http://www.honoluluzoo.org/spider_monkey.htm>.
“Wildfacts – Black-handed Spider Monkey”. BBC – Science & Nature. 28 Oct. 2006.
<http://www.bbc.co.uk/nature/wildfacts/factfiles/310.shtml>.
Author. "Title of Web Page." Title of the Site.
Editor. Date and/or Version Number.
Name of Sponsoring Institution. Date of Access
<URL>.
Appendix
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FIGURE 1
FIGURE 2
FIGURE 3
Appendix (cont.)
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FIGURE 5
FIGURE 6
FIGURE 7
Journal
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Wolf’s Guenon
They perform an array of acrobatics in the trees.
They chase the other monkeys back and forth.
It appears to be only social playing with each other.
One continues to chase another through the cage.
They swing by grabbing with front feet.
They have an extremely long tail (relative to their body size).
It appears to be used for balance (not prehensile).
Able to grasp with feet instead of tail to hang upside down with.
One cracks up a nut in its teeth, but has trouble, so it slams the nut down while
making a screaming noise, breaks the shell, and then eats it, by rotating it in its
mouth.
It now appears to be licking its hands, although it can’t be confirmed from this angle.
The monkey now fought with another monkey and they engage in a 50 second chase,
but then quickly make up.
They are very focal monkeys, always “talking” with each other.
One rubs its body against the ground in a playful way beside another.
This does not appear to be scratching, but rather just playing.
Able to scale the cage wall and then jump to a rope very quickly.
They are sitting on the rope and swinging it back and forth, playing with one another.
The left most monkey is obviously pissed off at the swinging and tackles the right
most monkey, they engage in a strong fight and scream at each other, then go to
another side of the cage.
One jumps into a hanging bucket, but falls out, then picks up a newspaper and
“reads” it.
It is able to hold on to objects with still moving very easily.
They eat constantly, often playing with their food.
They seem to enjoy being on the ground as much as being in the trees, but often relax
only in the trees and do not lay on the ground for rest.
Walks on all fours and does not sit up very much.
Another monkey comes down and begins to shred the newspaper into thing
rectangular strips.
Moves in a slinking manner often, especially when going slow. When fast, the same
but harder to see because of the motion.
Cracks nuts in teeth by moving them in a semicircular fashion.
Scratches and cleans itself every few minutes without fail.
Fascinated with hanging upside and trying to jump into the hanging bucket (which it
fails at).
Capable of moving on the underside of a branch, although this is rare, usually done to
avoid cross traffic.
Stands on the highest structures to survey the lands (albeit small lands).
Arguments over food creates another dispute, this time more serious with much more
focalization.
A small child screams at the monkey and the monkey flees to the top of the cage.
They often drop food only to recover it later for both play and consumption.
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Notices my presence and stares at me for around 10 minutes and does not much else.
It goes to chew on the ropes and then decides to swing on them.
Shakes back and forth on ropes for their amusement.
Seems to use tails for balance overall.
Scratching of the body by using both back and front feet; appears to be able equal.
Balancing upside down on the fountain area to get water (fails first time).
A monkey was able to grab a peanut from the underside of the cage by stretching.
Makes a very high pitched sound when interacting with others.
They seem to enjoy playing with each other’s tails but often playing turns into heated
fights.
Sharing food by swapping it between members in the cage.
Generally, after eating, they will go to get more water.
They often flip upside down first to reach the ground.
They sit with their legs straight out, resting on the log.
They finally get into the bucket without failing as they have for the past hour.
Monkeys started hugging but then ended up chasing each other.
They are interested in humans and routinely stare.
They can either break the peanut open in their mouth or often slam it on the ground to
get inside.
They mix eating with their hands and feet.
Both monkeys appear to be female
There does not appear to be a dominant or submissive in the relationship.
A child throws a peanut into the cage and the monkeys briefly fight over it.
A man sees this, and throws a cigarette butt (can you smoke in the park?!) in the cage,
laughs at the monkeys fighting over this.
They play with the cigarette butt (put it in their mouth) and then rip it apart.
They seem to cooperate when trying to reach objects outside of the cage, then fight
over whoever get its.
They don’t seem to be completely arboreal.
They generally vocalize when playing or when angry. (Or just when interested in
things.)
One monkey will sometimes tackle another, causing a large fight.
One stretches out on a rope and manages to keep a balance, then rests.
They don’t appear to groom each other but they do like to hug / choke another.
They engage in fighting by grabbing each others hands.
They become interested in a caterpillar walking by on the outside of the cage.
One is able to grab it, and then plays with it, then kills it by slamming it on the
ground until it does not move. It is then ripped apart and eaten.
They slide around the cage when not walking to get places.
When intimidated with another, they put their tails in the air.
They lie together and do not move for a long time.
There is a wasp and they follow it around the cage, but do not grab it.
They pick up the cigarette but and rip it apart some more, pulling the leftover tobacco
out and split it up on the ground.
They tire from playing and lay on the ground (branch).
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Black-handed Spider Monkey
2 monkeys are visible in the enclosure (possibly more though).
Both are currently sleeping (1:10P)
Birds near enclosure making loud noises do not interrupt the monkeys.
One appears to be male.
They continue to sleep, resting on a long “branch”, occasionally shifting positions.
One makes a small whimper-esque sound.
The male stands up and looks around, then rests again.
Extending from both sides of body, potentially about two feet long, possibility 2.5.
A very long tail, definitely appears to be prehensile. Maybe ¾ body size?
The tail extends from the end, as if rippling to the body.
One continues to sleep, while the other moves around subtly.
The male moves to a different area, around a branch, away from another monkey.
The male continues to move, now observing the people and looking on for several
minutes intently.
Now it observes a nearby monkey in much the same still fashion
4 Minutes – Observes a small bird around enclosure area.
The male goes back to the original monkey and lies down in the same place as 1:10P.
Has a very sleepy look and then looks again at people, then stares at the ground.
Another awakes and moves to the right of the enclosure.
Now, it hunches over and sleeps some more, not moving much.
Hair is very strong in color (especially on hands, bands on face), possibility to blend
in with matching environments?
Marked into “troops” (says a passing by class)
Monkey makes a small jump to another branch and then touches the male, then sits.
Again, very passive observation of people in the vicinity.
The other is still sleeping.
Lays down on ground, then jumps to branch, then lays down, letting arms rest over
the side of the branch.
Quickly stands up, goes to the other monkey. They make a small, almost inaudible
noise at each other, then settle down.
Seem to be very natural climbers, but have not shown much activity.
There is still no movement (10 minutes)
One gets into a crouching position but does not do anything, possibility sleeping or
relaxing.
There is a noise behind the enclosure, all of the monkeys look at it, but nothing
happens.
One is interested, goes to investigate, but then returns to the original sitting area and
relaxes.
The other monkey appears to use its left arm as a pillow.
The male monkey sits down and makes a small noise – the others do not look.
One decides to climb upwards and lay down on a branch.
Again, little movement but what is seen is brachiation. Is this after feeding time? Nap
time in the middle of the day?
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Does not appear to have a thumb, or it is just very small, but probably the latter.
They make sharp noises this time, when one runs around and jumps on another, but
then they go back to resting.
They again focus on the viewers, but then tired and looked to the back of the cage.
One became excited again and another jumped around as well, but they did not
engage each other.
Monkey seemed to enjoy a ball like, fetal position for sleeping and resting, though
others seemed to like stretching out more. Maybe a personal preference?
Monkey is still not doing anything. Passing by employee says they usually are more
active but are not today. When asked why, said they did not know (weather was fine).
One picks up some unrecognizable object and begins to either eat or play with it.
The other comes down to investigate and then rips apart a small stick.
The male rubs his leg up and down.
They continue to lounge with random intervals of play.