Staff at the sanctuary in Pittsboro, North Carolina worked for over a day running IV fluids and other supplemental therapies to cool Sheba down.
Staff managed to stabilize her, but the next morning, the 17-year-old lion wasn't responding and her kidney and liver began to fail.
"After working for so long to try to bring her back, we had to make the heartbreaking decision to let her go,” the sanctuary's post says.
Lions are expected to live about 10 years in the wild, so she was already quite old and her body succumbed to the heat, according to the sanctuary.
Sheba was the matriarch of a pride of three lions that came to the CTR from Texas. As a cub, she was once walked up and down the beaches of Cancun for profits.
They say she always kept two other lions in line, Sebastian and Tarzan, and she had great confidence and leadership with her pride.
She wasn’t afraid when she first arrived at the CTR and spent time walking around when she got there, sniffed every corner and stood on her hind feet to check out the roof.
The post says Sheba stands out as the epitome of what it means to be a lion: strong, confident and smart.
Carolina Tiger Rescue is a wild cat sanctuary devoted to saving cats in captivity and in the wild, according to its website. The nonprofit works to rescue cats that have been abandoned, rescued or given up.