This presentation is the result of a semester long research project. The slides contain a lot of text to ensure that disabled students are able to follow.

1. Gorilla beringei graueri
By Jaclyn Janero
Gorilladoctorsblog.com

2. {Introduction}

3. Grauer’s gorilla’s classification
down to the subspecies level.
Grauer’s gorilla classification
down to the genus level.
Jaclyn Janero

4. Range of Eastern gorillas, with Grauer’s
gorilla marked in green.
wikipedia.org
Grauer’s gorilla has three
prominent populations:
- Maiko National Park,
- Kahuzi-Biega National Park,
- Itombwe Natural Reserve
All three are in the Eastern
Democratic Republic of Congo
in Africa (Mittermeier, 2012).

5. Grauer’s gorillas occupy habitats from
lowland tropical forests to higher montane
forests (Yamagiwa, 2005).
Baraza.wildlifedirect.org
Map of gorilla distribution with terrain.

6. Grauer’s gorillas are
diurnal, with intense
morning feeding and an
additional eating phase
in the late afternoon.
This second eating phase
is followed by a dusk-
time nest building
session (Remis, 1997).
www.wcs.org
Gorilla beringei graueri during nest building.

7. A Western Lowland Gorilla exhibiting
knuckle-walking.
Wikipedia.org
Gorilla beringei graueri
travel on the ground by
knuckle-walking but use
forelimb suspensory
adaptations in trees.
Males are cautious in
trees and tend to stay
closer to tree trunks;
youngsters and females
can move further from
the trunk since they
have lower body mass
(Doran & McNeilage,
1998).

8. G. b. graueri is omnivorous. Fruit consumption increases when
fruit abundance is high. They also eat copious amounts of bark.
Grauer’s gorillas have a preference for figs, as do sympatric
chimpanzees, making competition for this fruit high. The two
species often encounter one another around fruiting trees;
neither will approach the other, leaving the population who
finds it first free to forage.
Grauer’s gorillas have been observed eating insignificant
amounts of animal proteins. In times of food shortage, Grauer’s
gorillas engage in geophagy and rotten wood consumption.
Their total body mass also allows them to fall back on leaves.
Consumption of whole Commelina cecilae leaves, without
chewing, may trap and expel parasites, such as nematodes,
making this a medical endeavor (Yamagiwa, 2005).

9. Grauer’s gorillas
have multimale-
multifemale social
structures.
Males and females
tend to leave their
natal groups around
maturity. Females
immigrate into
other groups or join
solitary males to
form new groups.The range of Gorilla beringei graueri group size is
from 2 to 20 individuals (Yamagiwa, 2003).

10. Mungaiaandthegoaconstrictor.wordpress.com
Females have a 25 year
reproductive life with a 4.6 year
interbirth interval.
Females become reproductive
around age 6 (Czekala & Robbins,
2001) and each successfully
produces an average of 3 to 5
offspring before her death.
There is a 26% infant mortality
rate (Yamagiwa, 2003). Though
groups have a dominant male, the
silverback, it is the female who
chooses her mate. Females may
copulate with both silverback and
blackback males (Bradley, 2005).
Mother Grauer’s Gorilla with Infants

11. Usually there is only one silverback in a social group.
However, silverbacks do not monopolize reproduction in groups
with multiple males. Females prefer the silverback, but avoid
breeding with relatives. Hence, blackback males are
sometimes chosen (Bradley, 2005).
A Male Eastern Lowlands Gorilla in Threat Posture

12. {Conservation}

13. According to the IUCN Red List, Gorilla beringei graueri
is endangered with expectations of population
decline in the future of nearly 50%.
This aligns with additional conservation data I have obtained
from other sources. However, population numbers and range
tend to fluctuate (Mittermeier, 2012). One researcher pinpoints
smaller populations and their locales as being just as important
to preserve as the top 3 endangered primates designated in the
IUCN Red List (Nixon, 2006).

14. The IUCN reports 2,000 to
10,000 individuals across all
populations of Grauer’s gorillas.
The reason for disparity in
reports is that the Democratic
Republic of Congo is a war zone,
making accurate data difficult
and dangerous to obtain.
Remote sensing techniques
have been utilized, but not
effectively (Nixon, 2006).
A very basic diagram of remote sensing.
Coolclassroom.org

15. Poaching, as well as hunting
for bushmeat, is a major cause
of population decline.
Silverbacks are killed for the
sale of their pelts. In 2005, five
silverbacks were killed around
the same time, resulting in
havoc for the affected gorilla
communities, which took
months to recover.
A silverback can also be killed
by refugees in order to honor
transactions with local
businessmen (Kasereka, 2006).
Poachers Showing the Backpack They Smuggle Gorilla Infants In
Virunga.org

16. In 1996, park rangers in the Democratic Republic of Congo
were disarmed, allowing poachers to run rampant.
Gorillas were massacred until the rangers were eventually
re-armed in May of 2000 (Kasereka, 2006).
Gorillas.org

17. Habituated gorillas and those that are settled into a social
group are less aggressive. They generally don’t defend
themselves from poachers and are easy targets. Habituated
gorillas are hunted mainly for their meat and to capture infants
for illegal export and resale (Kasereka, 2006).
Wexas.com

18. Other threats include deforestation and cattle encroachment.
Many gorillas are wounded by antelope snares as a side effect
of human habitation (Yamagiwa, 1992).
A Ranger Stands With Two Months of Found Snares

19. Human population
density has recently
increased due to the
influx of refugees
from Rwanda. This
creates pressures on
the environment.
In 1998, Gorilla
beringei graueri had
no contact with
populations that were
further apart
geographically
(Saltonstall, 1998).
Rwandan Refugee Camp in Democratic Republic of Congo
Map of the UGADEC
corridor (in orange) in
the DRC.

20. Charcoal production, mining, and slash-and-burn agriculture are also
prevalent. In 2000 and 2001, approximately 15,000 people migrated to
the park to mine coltan when the price skyrocketed by more than 10
times. Coltan is refined into tantalum, a heat-resistance powder that
holds a high electrical charge. It is used in almost every electrical device
that is currently produced, most notably cell phones.
An Example of Slash-and-Burn Agriculture
Ecos.efpl.ch

21. These human activities caused permanent damage.
This damage was greatest in the corridor that connects the
main populations of Grauer’s gorilla. By 2008, 60% of the
corridor was degraded (Yamagiwa, 2012).
An Example of Slash-and-Burn Agriculture
Ecos.efpl.ch

22. Closure of public services, such as clinics & transportation,
increased the need to use park plants and vegetation for
construction, food, fuel, and medicine. Starvation brought on by
the economic and political crisis increased food needs, pushing
people to use more park resources (Yamagiwa, 2012).
Worldwildlife.org
Refugees Taking Park Resources for Fuel in Virungas Park, DRC

23. When the parks were created, many people were displaced
from their homes and areas of cultural significance. They were
also prohibited from shooting elephants that frequently raided
and destroyed their crops. These individuals live on the
outskirts of the park and frequent it for resources, further
depreciating the park (Yamagiwa, 2012).
Coconut Trees Destroyed by Elephants
Seeingthewoods.org

24. To prevent further species
loss, parks should work
on restoration and
preservation of the
corridor that connects
the gorillas, to prevent
genetic isolation
(Saltonstall, 1998).
A Map of the Democratic Republic of Congo, Showing the
Corridor Between the Two Parks (UGADEC)
Janegoodall.ca

25. Patrols of the parks by armed rangers need to be more frequent
to watch for traps and poachers (Yamagiwa, 1993). Surveillance
of the entire park, instead of just the tourism area, needs to be
implemented (Kasereka, 2006).
Park Rangers in the Democratic Republic of Congo on Patrol
Boingboing.net

26. Cooperation with local populations and refugees may be the
Grauer’s gorilla’s best chance, as well as the impacted human
populations. Yamagiwa et al (2012) provide five comprehensive
alternative solution outlines for this, which I agree with:
• Promote local animal breeding projects and fish farming to increase the
availability of off-park resources
• Plant trees in excess to supply communities with wood and other resources
to be managed rationally
• Promote farming to increase food stability and security while educating the
community on sustainable practices
• Promote projects that use sustainable techniques to meet fuel needs and
implement management strategies for farming (IE: vegetable oil from
locally grown peanuts or sunflowers)
• Promote income activities that also increase economy; can include
development of a fair trade system alongside ecotourism

27. Why is Grauer’s Gorilla conservation an anthropological concern?
Grauer’s gorillas are closely
related to humans, a relationship
emphasized by both Darwin &
Huxley; they connect us to our
ancestral past (Scally, 2012).
Sadly, they also provide evidence
of “unnatural” extinction and
population fragmentation and
crises due to human actions.
For these reasons, the
conservation of Grauer’s Gorilla
is of anthropological concern.
Plus, they are adorable!
Mungaiandthegoaconstrictor.com
Vetstreet.com

28. Works Cited
• Bradley, Brenda J., with Martha M. Robbins, Elizabeth A. Williamson, H. Dieter Steklis, Netzin Gerald Steklis, Nadin
Eckhardt, Cristophe Boesch, and Linda Vigilant. 2005. Mountain Gorilla Tug-of-War: Silverbacks Have Limited Control Over
Reproduction in Multimale Groups. PNAS 102(26): 9418-9423.
• Czekala N, with Robbins MM. 2001. Assessment of reproduction and stress through hormone analysis in gorillas. In: Robbins
MM, Sicotte P, Stewart KJ, editors. Mountain gorillas: three decades of research at Karisoke. Cambridge (England): Cambridge
Univ Pr. p 317-39.
• Doran, Diane M., with Alastair McNeilage. 1998. Gorilla Ecology and Behavior. Evolutionary Anthropology 120-131.
• Kasereka, Bishikwabo, with Jean-Berckmans B. Muhigwa, Chantal Shalukoma, and John M. Kahekwa. 2006. Vulnerability of
Habituated Grauer’s Gorilla to Poaching in the Kahuzi-Biega National Park, DRC. African Study Monographs, 27(1):15-26.
• Mittermeir, Russell A., with Christoph Schwitzer, Anthony B. Rylands, Lucy A. Taylor, Federica Chiozza, Elizabeth A.
Williamson, and Janette Wallis. 2012. Primates in Peril: The World’s 25 Most Endangered Primates 2012-2014.
• Nixon, S.C., with K. Mufabule, D. Bolamba, B. Mulley, and P.T. Mehlman. 2006. Landscape-Wide Conservations Status and
Distribution of Grauer’s Gorillas (Gorilla beringei graueri) In Eastern Democratic Republic of Congo (DRC). International
Journal of Primatology 27:427.
• Remis, Melissa J. 1997. Ranging and Grouping Patterns of a Western Lowland Gorilla Group at Bai Hokou, Central African
Republic. American Journal of Primatology 43:111-133.
• Saltonstall, K., with G. Amato and J. Powell. 1998. Mitochondrial DNA Variability in Grauer’s Gorillas of Kahuzi-Biega
National Park. Journal of Heredity 89:129-135.
• Scally, Aylwyn, et al. 2012. Insights Into Hominid Evolution From The Gorilla Genome Sequence. Nature 483:169-175.
• Stanford, Craig B. 2001. The Subspecies Concept in Primatology: The Case of Mountain Gorillas. Primates 42(4):309-318.
• Yamagiwa, Juichi, with Ndunda Mwanza, Andrea Spangenberg, Tamaki Maruhashi, Takakazu Yumoto, Antja Fischer, and
Bernd Steinhauer-Burkart. 1993. A Census of the Eastern Lowland Gorillas Gorilla gorilla graueri in Kahuzi-Biega National
Park with Reference to Mountain Gorillas G. g. beringei in the Virunga Region, Zaire. Biological Conservation 64:83-89.
• Yamagiwa, Juichi, with John Kahekwa and Augustin Kanyunyi Basabose. 2003. Intra-specific Variation in Social Organization
of Gorillas: Implications for Their Social Evolution. Primates 44:359-369.
• Yamagiwa, Juichi, with Augustin in the Montane Forest of Kahuzi, Kiswele Kaleme, and Takakazu Yumoto. 2005. Diet of
Grauer’s Gorillas in the Montane Forest of Kahuzi, Democratic Republic of Congo. International Journal of Primatology
26(6):1345-1373.
• Yamagiwa, Juichi, with Augustin Kanyuyi Basabose, John Kahekwa, Dominique Bikaba, Chieko Ando, Miki Matsubara,
Nobusuke Iwasaki, and David S. Sprague. 2012. Long-Term Research on Grauer’s Gorillas in Kahuzi-Biega National Park,
DRC: Life History, Foraging Strategies, and Ecological Differentiation from Sympatric Chimpanzees. Long-Term Field Studies
of Primates: 385-412.