A newly born Western Lowland Gorilla baby is held by its mother “Frala” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. The baby gorilla was born six days ago, and is the second sired by the zoo's new Silverback, Kibali, who arrived from France in 2012. (Photo by David Gray/Reuters)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother 'Mbeli' in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)

A newly born Western Lowland Gorilla baby is held by its Mother “Frala” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother “Mbeli” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother “Mbeli” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)

A newly born Western Lowland Gorilla baby holds onto its mother “Frala” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother “Mbeli” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. (Photo by David Gray/Reuters)