BROOKFIELD, Ill. — The Brookfield Zoo is mourning the loss of their red panda Leo.

Leo, 5, passed away suddenly, the zoo announced Wednesday morning. No cause of death was given.

He arrived at Brookfield Zoo in 2018, where “he quickly won over the hearts of his caretakers and zoo patrons while he spent time in his habitat at Hamill Family Wild Encounters.”

His favorite treats were dried cranberries and loved tearing up paper boxes.

According to the World Wildlife Fund, there are fewer than 10,000 red pandas in the world.