Rest in Peace
“We Go Si Bak” Mack



We go si bak” is Krio, spoken widely in Sierra Leone, for “Goodbye” or “Until we meet again.”  We use this phrase to bid farewell to our beloved Mack, who died peacefully in his sleep on August 22, 2010, at the estimated age of 46.  Mack was born in the 1960s in Sierra Leone, and was captured at a young age.  His mother and possibly other family members would have been shot and killed.  Mack was sold to the Delta Regional Primate Research Center (now called the Tulane National Primate Research Center) in Covington, LA.  He remained there for 14 years, but there is no record of what his life was like there.  In 1981, Mack was sold to The Coulston Foundation.  For the first ten years, Mack was used primarily as a breeder.  Every week to two weeks he would be placed with a different female chimpanzee, in the hopes that he would impregnate them.  Although he was placed with some of the females multiple times over the years, he was never allowed to form a lasting bond with any other chimp.  When he wasn’t living with a female, he lived alone.  Over the years, Mack fathered 28 children.

In 1990s, in between bouts of breeding, The Coulston Foundation used Mack in four different biomedical research protocols.  The studies required him to be anesthetized for several days in a row to receive an unknown “test material”, and he would have not been allowed to eat much food for those days.   For his last study, he was anesthetized two days in a row, for twelve hours each day, receiving a total of 94 ml of ketamine to keep him anesthetized.

Mack at The Clouston Foundation

In 2002, The Coulston Foundation went bankrupt; Save the Chimps, under the leadership of the late Dr. Carole Noon, rescued Mack and 265 other chimpanzees—including fourteen of his sons and daughters.  Mack was found living alone in “The Dungeon”—but he didn’t stay alone for long.  Mack was gradually integrated into a family group.  Despite no record of him ever meeting another male chimpanzee, Mack easily made friends with both males and females; his family also included several of his children:  Brandon, Patrick, Hailey, and Jasmine.

In 2006, Mack and his family moved to their island home at Save the Chimps in Florida.  Mack relished the wide open spaces of the island, running about the hills and platforms as if he were a teenager again.  Although his stature was small for a male chimp, he nonetheless commanded the respect of the younger (and sometimes much larger!) chimps in the group.  And though it was clear the years were catching up to Mack, his spirit never diminished.


August 22, 2010 was a normal day for Mack; he ate lunch with his family as always, and headed back out onto his island home.  That afternoon, Mack lay down in the shade of a tree for a nap, and passed away in his sleep.  Mack should have taken his last breaths in the forests of Sierra Leone where he was born, but we take comfort in the fact that Mack’s final years were free from suffering, and that his last moments were peaceful, in the company of his chimpanzee family.

Rest in Peace, Mack.  We go si bak.



To donate “In memory of Mack”, please click here.

On behalf of all the chimpanzees, thank you for your compassion and support.