Brookfield Zoo's JoJo the silverback gorilla dies following emergency medical procedure

The beloved gorilla JoJo died Sunday at Brookfield Zoo.

The silverback western lowland gorilla went into cardiac arrest during an emergency veterinary procedure prompted by an acute illness, according to the Chicago Zoological Society, which runs the suburban zoo.

JoJo was 42.

"JoJo was very smart and learned new behaviors quickly during husbandry training sessions. He was known for keeping order in the gorilla group by quickly breaking up squabbles and often showed his gentler and patient side when interacting with his offspring," according to a statement posted Monday afternoon on the zoo’s Facebook page.


The Facebook message quickly generated hundreds of comments, including "RIP BIG GUY" and "May this gentle giant Rest In Peace."

A spokeswoman for Brookfield Zoo did not return messages seeking more details of the death.

JoJo, who weighed 485 pounds, was a senior citizen in gorilla years.

The median life expectancy for male gorillas in managed care is 32 years, according to the zoo.

"We will miss JoJo dearly," officials said.

But his legacy will live on among the critically endangered species.

During his 10 years at Brookfield Zoo, JoJo sired three offspring — Zachary in 2015, Nora in 2013 and Ali in 2018.

He also sired an offspring in 2003 when he was at Louisville Zoo, and in 2004, he sired a female at Lincoln Park Zoo.

Brookfield Zoo posted several videos of JoJo over the years to YouTube, including one titled "JoJo celebrates 40th birthday" that shows the gorilla chomping on special treats.

Western lowland gorillas are considered a critically endangered species by the International Union for Conservation of Nature. Causes for their endangerment include habitat destruction and degradation, diseases such as Ebola and commercial hunting.