Western lowland gorilla photo: WWF-Canon / Fritz PÖLKING

Individual gorillas can be identified by their unique "nose prints," or nose patterns, and as with human fingerprints, no two gorillas have an identical nose print. Researchers often use photographs and illustrations of noses in order to identify and monitor individual gorillas.

Behavior
Gorillas live in family groups that generally consist of five to 10 individuals, although groups can sometimes be comprised of as few as two or as many as 35 individuals. These family groups are led by one dominant male, called a silverback because of the saddle of silvery white hair that extends down his back. Also part of the group are several mature females, their offspring and one or two adolescent males who stay with the group until they reach about 12 years old. Most of the young females leave their birth group to join another group or sometimes join a single male.

Female gorillas reach sexual maturity at 7 or 8 years of age, but do not start breeding until a few years later. Males, on the other hand, do not start breeding before the age of 15. Gorillas have a long gestation period of about 270 days, and usually give birth to one infant. They have long periods of maternal care and tend to successfully rear only one infant every 6 to 8 years.

Diet
Gorillas are mostly vegetarian and eat large amounts of vegetation from more than 70 different plant species, including wild celery, vines, berries, bamboo, roots and bark. A male gorilla can eat up to 75 pounds of bamboo a day, while a female can eat as much as 40 pounds. Western lowland gorillas also eat vast quantities of termites and ants. They spend approximately 30 percent of their day eating, 30 percent traveling and 40 percent resting and sleeping. Each evening, gorillas build themselves fresh night nests from surrounding vegetation in which they sleep.

Threats
There is a great deal of pressure on gorilla populations and they face increasing threats to their existence, driven primarily by unchecked logging practices. The roads required by the logging industry open previously inaccessible areas to hunters, facilitate the spread of disease and increase the rate of human encroachment and habitat loss.

• Habitat Loss
  Gorillas live in densely populated parts of Africa in forest habitats surrounded by rapidly increasing human settlement. As the need for land and food from the growing human population increases, the needs of people and gorillas come into conflict. In addition to the pressures of subsistence agriculture, the rainforest habitat of gorillas has become a target for timber companies: Large amounts of rainforest in western lowland gorilla habitat in the Congo Basin have already been lost or are leased out to European and Asian logging concerns.
• Hunting
  Gorillas are illegally hunted for food and body parts, and infants are sometimes captured and sold as pets. Bushmeat is often the only available or affordable source of animal protein for local communities in central Africa, and due to market demand also provides a source of income to some. There exists a thriving commercial trade in wild meat from rural areas of Africa to the rapidly expanding cities, and gorillas have become both intentional and unintentional victims. Great apes are a small proportion of the total species killed for the bushmeat trade, but they are frequently maimed or killed throughout their range by traps and snares intended for other forest animals. The number of gorillas killed each year to supply the bushmeat trade is unknown, as they are often butchered and killed on the spot, or meat is smoked for later sale in towns.
• Disease
  Disease is a potential threat that particularly affects groups of habituated gorillas that come into close contact with humans in areas where gorilla tourism is promoted. Humans and gorillas have a similar genetic makeup, which means that their physiology is similar enough to make gorillas vulnerable to many of the same diseases as people. However, gorillas have not developed the same immunities that humans have, and therefore humans are potentially a source of disease that, once transmitted to gorillas, could devastate the population.

  Additionally, the Ebola virus has swept through some of the strongest, high-density populations of western lowland gorillas in Central Africa. For instance, a 90 percent decline due to Ebola has been noted in the Minkebe National Park in Gabon, and the disease is spreading through human and ape populations along the Gabon-Congo border, and has been noted in other areas as well.