Utah’s Hogle Zoo announced on Friday the death of Diego, a California sea lion who made history as the biggest animal to get a CT scan at the University of Utah Hospital.
Diego had been suffering from degenerative disc disease, a spinal condition that impacted his mobility, especially in the rear flippers. Since his diagnosis in 2024, his caretakers have been providing ongoing treatments to aid his mobility and comfort.
Last October, the zoo caretakers knew something was wrong with Diego’s spine, so they undertook the massive endeavor of transporting Diego to the University of Utah imaging center, where he underwent a CT scan. The CT scan helped the vets see what was hurting him and where the worst of the disease was, so they could treat him more effectively.
Diego’s caretakers have been using laser therapy, habitat evaluations and medication to keep him as comfortable and happy as possible. On Monday, however, the zoo team noticed a sudden decrease in appetite, and he exhibited behavior indicating significant discomfort.
“Despite focused care and treatment in the days that followed, his condition did not improve. After careful consideration, the animal care and veterinary teams made the difficult decision to euthanize Diego. He was surrounded by his keepers and hospital staff who cared for him, ensuring he received the best possible care throughout his life,” the zoo said in a statement Friday.
Diego was known for his loud vocalizations and curious personality, the zoo said. He arrived at the zoo in 2017 and quickly became a guest and staff favorite.
“Diego’s care team described him as an incredibly special sea lion full of personality. He loved sardines and playing in the water. He was eager to learn new things and participate in fun, challenging games during training sessions, creating unique bonds with his trusted care team,” the zoo said.