Gorillas: The World's Largest Primates
{{#rendered}} {{/rendered}}Hasani, the 7-month-old infant western lowland gorilla, rides on the back of his surrogate mother at the San Francisco Zoo, as another member of the troop walks in the background on July 2, 2009 in San Francisco. (AP)
Hasani, a six-month old western lowland gorilla, rides in the back of his surrogate mother Bawang at the San Francisco Zoo in San Francisco on June 5, 2009. (AP)
Female gorilla 'Gana' nurses her five days old offspring at a zoo in Muenster, Germany on Aug. 7, 2009. (AP)
Female gorilla 'Gana' mourned very publicly when her last baby passed away. In this photo, taken on Aug. 4, 2009, Gana holds her two days old offspring at a zoo in Muenster, Germany. (AP)
A mother gorilla looks lovingly at her offspring at a zoo in Muenster, Germany, in Aug. 2009. Infant gorillas stay with their mothers for up to four years. (AP)
A six-month old western lowland gorilla is carried by his surrogate mother Bawang at the San Francisco Zoo in San Francisco, Friday, June 5, 2009. (AP)
A mother gorilla spends time with her infant in Muenster, Germany. The life span for a gorilla is 30 to 50 years. (AP)