Sunday, March 25, 2012

Conservation Status

We have already learned that Gorillas typically reside in tropical forests (with the exception of the Mountain Gorillas, which live in the mountains).  We also know that in recent years, humans have slowly been destroying forests throughout the world, due to our increasing populations and need for more residential and industrial space.  For this reason, all subspecies of gorillas are considered "endangered" because the largest threat to the gorilla population is habitat loss, which can be due to deforestation, wood extraction, infrastructure development, and human settlement.  Other threats to gorillas include direct killing for bushmeat trade, hunting for live animal trade, and diseases transmitted by humans, war, and political unrest.  Since gorillas share about 98% of the same genes as humans, they are very susceptible to catching human diseases, and vise versa.

On the plus side, many programs in Africa, as well as other parts of the world, have been established to protect gorillas.  For instance, there are laws in eight different African countries that govern gorilla hunting and capturing.  In addition, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international trade treaty that was developed in 1973 to regulate trade in certain endangered species, which includes gorillas.  Also, in 2000, the United States congress passed the Great Ape Conservation Act, which provides financial support for conservation projects that protect great apes in the wild.  

You can help too! The next time you buy wood or furniture, be sure to ask if it has been certified.  This means that the wood was taken in a way that has been approved by forestry experts.  Buying certified wood will encourage logging companies in Africa to follow wildlife laws that will help protect gorillas and other African animals.  Also, be sure to check out the gorilla exhibit at the San Diego Zoo!


Tuesday, March 20, 2012

Reproductive Behavior of Gorillas

Reproductive Behavior of Gorillas

Mountain Gorillas are polygynous, which means that the dominant males have access, and permission, to reproduce with all of the females in the group. However, the females are only able to birth an infant approximately every 4 to 5 years because she ceases to ovulate for a few years after birth. Therefore, the average number of offspring usually tends to be only one. Reproductive rates are also fairly slow, and if a female chooses to birth more than one offspring (anywhere from 2 to 6), it can be over the span of 40 years. This is why the males attempt to reproduce with more than one female, so they can increase the amount of offspring from their lineage. A male gorilla may father anywhere from 10 to 20 offspring over the course of 50 years.

         Mating behavior does not begin until the gorillas are sexually mature, which is about 10 years old for females, and 15 years old for males. Gorillas usually are nursed and cared for by their mother for the first three to four years of life, and then the toddlers stay with their group until they are sexually mature to leave. Females will go out and wander by themselves in search of a new group, and males venture off when they are about 12-13, recruiting new members and bachelors for their own new troop. (This prevents inbreeding). Unlike many animals, the female is the one to initiate mating behavior by slowly approaching the male, as well as giving off a specific odor that the males will pick up on when she is ready to mate. Gorillas are also “one of the only known animals to engage in different sexual positions other than humans,” (

         Because of the time and maturity devoted to having one offspring, gorillas are said to be one of the best caregivers in the animal world. They provide the basic needs as wells as giving their children lots of affection. The mothers hold their babies similarly to human mothers and take their job of protecting their young very seriously.