The San Diego Zoo announced that M'bari, its 15-year-old male lion, died Wednesday due to age-related medical issues.
M'bari had been under veterinary care and his health worsened in recent days, according to the zoo.
Staff made efforts to modify M'bari's habitat to make him more comfortable, but because of his worsening quality of life the zoo decided to humanely euthanize him.
M'bari spent most of his time with his mate Etosha in their habitat at the Harry and Grace Steele Elephant Odyssey. The zoo said his early morning and late afternoon roars could be heard throughout the entire compound.
"Please share your condolences with staff, volunteers, members, and guests who remember him from countless visits and will especially be feeling this loss," the zoo said in a statement.