The most abundant of the gorilla subspecies, and is also the typical gorilla seen in captivity.
The most recently discovered subspecies of gorilla, and fewest in number. Morphologically the Cross River gorilla is more gracile than the western lowland gorilla. Originally described as a distinct subspecies in 1904.
The Eastern Lowland Gorilla is the largest subspecies of gorilla.
Between 300-600 Mountain Gorillas are left. Diane Fossey is the Primatologist most associated with these.
Note arms are longer than the legs, and the knuckle walking posture.
Maternal care is a learned behavior in gorillas. Photos from Brookfield Zoo.
Bwindi Impenetrable Forest Gorillas may be intergrades between graueri and beringei.
There is the possibility of a new gorilla subspecies from northern Zaire being investigated.
Gorillas in our midst.
Gorillas In Our Midst.• The Gorilla: The Largest Living Species of Primate.
Gorilla Taxonomy.• Up to four subspecies of Gorilla gorilla are currently recognized.• I: Western Group:• A) Gorilla gorilla gorilla, The Western Lowland Gorilla.• B) G. g. diehli, The Cross River Gorilla.• II. Eastern Group.• C) G. g. graueri, The Eastern Lowland Gorilla.• D) G. g. beringei, The Mountain Gorilla.
Gorilla Morphology.• Large Size.• Arms longer than legs.• Sexual dimorphism in size, males up to 200kg, females 70-100 kg.• Knuckle walkers/quadrupedal.• Sagittal Crest, especially in males.• Subpecies differentiated by shape of nostrils, relative size and robusticity, and body hair.
Gorilla Polygynous Social Groups.• Groups composed of one adult “Silverback” Male and several females, plus offspring.• Group numbers range from 7-11 individuals in mountain gorillas.• Immature “Blackback” males may remain with group until maturity.• Mountain gorillas are the most studied subspecies.
Gorilla Home and Day Range.• Gorilla home ranges vary depending on the habitat and subspecies in question.• Home ranges can be as large as 100 ha.• Day ranges average about 500 meters.
Gorilla Diet.• Gorillas are the most folivorous of the Great Apes.• Some fruit is eaten.
Gorilla Reproduction.• Extreme K selection.• Gorillas give birth to one offspring at a time.• Gestation is about 256 days.• Birth intervals between 36 and 59 months, depending on the subspecies.
Conservation Status of Gorillas.• All Gorilla subspecies are protected by CITES• Habitat loss is a major threat.• Poaching and the bushmeat trade are major threats too.• Diseases, such as Ebola, have devastated both gorilla and chimpanzee populations in the Odzala National Park in Zaire.
Population estimates.• Between 10,000 and 20,000 Western Lowland Gorillas.• Up to 10,000 Eastern Lowland Gorillas.• Between 350 and 650 Mountain Gorillas.• Between 100-200 Cross River Gorillas.
Gorilla survival in the future.• Depends on Ecosystem and Habitat protection.• Protection from poaching and bushmeat trade.• Reproduction in captivity.• New discoveries?