Gorillas are the largest primates alive today. They live throughout Africa, and are divided into subspecies dependent on their environmental habitats. Gorillas are considered extremely intelligent, and studies have observed their use of tools and sophisticated group dynamics.
At birth, a gorilla weighs four or five lbs (1.8-2.2 kg) and remains dependent on its mother for about six years. Adult male gorillas typically weigh between 300-500 lbs (137-227 kg) and achieve a height of around five and a half to six feet (1.7-1.8 m.) Females are far smaller than males, usually weighing between 150-200 lbs (68-91 kg) and rarely more than five feet (1.5 m) tall. The coloration of gorillas varies between subspecies, ranging from nearly black in Eastern Mountain gorillas to reddish-brown in the Western Lowland subspecies.
Gorillas live in family groups, comprised of 5-20 animals. The leader of the group is an adult male called a silverback, in reference to the distinct silver patch that appears on male gorillas after age 12. Around age 11, most male gorillas break off from their group and try to attract mates to form their own family. Males younger than 12 are called blackbacks, and follow the silverback’s lead until they choose to leave, although they occasionally attempt to overthrow the senior male and assume charge of the group. Studies show that hostile takeovers are rare, and group leadership usually changes only when the silverback dies of disease or is killed by poachers.
The diet of the gorilla is generally herbivorous, but they are occasionally sighted eating small insects. Mostly, they subsist on fruit, young plant shoots and leaves. Because they must constantly eat, gorillas spend much of their time on the move, searching for new food sources. Their simple diet is in direct contrast to early portrayals of behavior, which suggested these usually gentle primates were fierce hunters with inherently violent natures.
A study conducted in 2005 confirmed the common belief that gorillas sometimes make use of tools, similar to chimpanzees. Female gorillas in the Republic of Congo were observed using sticks to discover the depth of bodies of water, and making crude bridges from tree stumps. Other gorillas were seen using rocks to smash open nuts. Tool usage is believed to be indicative of high intelligence, and the recent findings have caused some experts to reassess their opinion of the species brain capacity.
One famous gorilla, named Koko, was able to learn a form of sign language to communicate with handlers. Experts differ on whether Koko’s abilities meant that she truly speaks the language or simply has learned to use it for rewards. Handlers insist that Koko invents words herself, combining signs she already knows for more complex definitions. Koko also is known for keeping cats as pets, expressing caring behavior such as petting and grooming them.
All subspecies of gorilla are listed as endangered by various US and international wildlife agencies. Habitat destruction and persistent poaching in gorilla sanctuaries are seen as main contributors to the dire situation of the species. In 2004, a population of several hundred gorillas died from an outbreak of the Ebola virus. Recent studies suggest the species may be particularly sensitive to Ebola, and more than 5,000 animals are believed to have died from it.
Many organizations are dedicated to conservation efforts for gorilla species. If you wish to aid attempts to the species, donation and volunteer opportunities are readily available. Many zoos also offer adopt-a-gorilla programs, with proceeds going to fund research and conservation of these giant primates.