- Western gorillas live in dense forests in western central Africa. They are the largest primates and live in family groups led by a dominant silverback male. - Gorillas communicate through vocalizations like growling, hooting, and crying, as well as nonverbal cues like chest beating. The silverback protects the family group and establishes dominance. - Gorillas are herbivorous and forage for plants. Females care for offspring for several years. Gorilla families are led by a dominant silverback male who protects the group.

1. Western Gorilla
DANIEL RAMIREZ, MORGAN GILLEY
VERTEBRATE ZOOLOGY SUMMER 2017
LAB REPORT C
UNIVERSITY OF CENTRAL ARKANSAS

2. Objectives
• Background (Habitat, features, evolutionary history)
• Communication (verbal and nonverbal)
• Behavior

3. Taxonomy
• Common Name: Gorillas
• Scientific Name: Gorilla gorilla
• Order: Primates
• Family: Great Apes
• Closest Relative in Arkansas:
Humans
Figure 1. Mammalian cladogram
(slideshare.net).

4. Habitat and Geographical Location
• Cameroon/Gabon, Africa
• Ethiopia
• Lowlands of Africa’s Tropical
Secondary forests
– Dense forest -perfect for Gorilla’s
diet
Figure 2. Gorilla Geographic Habitat
(Zoo.org)

5. Appearance & Food
• Largest primate, no tail, jet black skin, dark hair
covers body except for the face, hands, feet, & ears
with brown hair on the top of the head & back, large
hands with a very large thumb, short muzzle ,
prominent brow bridge, small ears & eyes, large &
strong jaw muscles & teeth
• Silverbacks: older males with gray hair on their
back & rump
• Males: 180 kg, 1.75 m tall
• Females: 90 kg, 1.25 m tall
• Herbivores-stemmed plants, berries, leaves
• Feed in the morning & afternoon 15 m up in trees
Figure 3. Gorilla eating a
stemmed plant (Sce-
News.com).

6. Gorilla Communication and Behavior
• Nonverbal
– ‘Silver back’ depicts sexual maturity
for males
– Power
• Size
• Protection -beating chest; charge
intruders
• Dominance in the troop
Figure 4. Gorilla gorilla
(BetterLIfeCoachingBlog)

7. Gorilla Communication and Behavior
Cont’d
• Verbal
– Growling
• Warning for intruders/competitors
– Hooting by dominant male
• Causes members of troop to acknowledge
dominant male
– Mother nurturing
• Find food, socialize with rest of troop, offer
support or discipline, locating one another.
• Infants are suckled for up to 3-4 years
– Babies also communicate with the mothers
i.e. crying and whining
Figure 5. Mother interacting with
her offspring (Gorillas World)

8. Gorilla Behavior
• Mom & baby playing
• https://www.youtube.com/watch?v=
Ac6p7T2Bc00
• Chest Pounding -Communication
• https://www.youtube.com/watch?v=
lk2udXac7nU
Figure 6. Gorilla pounding chest
(Sendirimu)

9. Hierarchy and Reproduction
• Polygynous
• No breeding season, 9 month
gestation period, menstruation every
28 days, birth every 4 years starting
at age 15 for males & 10 for females
• Babies are dependent on mother for
3-4 years
• Males do not care for the infant, but
does protect them
against infanticide males
• New Dominant male commits
infanticide
• Average lifespan: 35-50 years old
Figure 7. Mother & baby gorilla
sleeping (ZooBorns).
Figure 8. Gorilla family with
caring mother & protecting father
(kansascitynews).

10. Observational Learning
• Using tools
• Males entering manhood
• Much like humans, baby
gorillas are constantly being
fed vast amount of
information via verbal and
nonverbal communication
Figure 9. Gorilla using tool (Pinterest)
Figure 10. Baby gorilla mimicking
older gorilla

11. Questions?

12. Sources
• http://www.gorillas-world.com/gorilla-communication/
• http://animaldiversity.org/accounts/Gorilla_gorilla/
• Title slide picture (DailyMail)