JoJo the silverback gorilla dies after emergency procedure at Brookfield Zoo

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.

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