Zenda, 25, believed to be the oldest lion in the United States, died Thursday at the Philadelphia Zoo.
She was slight for a lion, said Kay Buffamonte, her keeper for 24 years, but she was a peacemaker. She'd calm her family if there was a disagreement over space or a favorite toy.
"She was the one that held everyone together," Buffamonte said.
Zenda, who had been in remarkable health for a lion of her age, declined quickly. On Monday, she enjoyed her favorite meal, 10 pounds of raw muscle steak wrapped around a bone. By Wednesday, she was in distress. On Thursday, she was euthanized.
Zenda was born at the Johannesburg Zoo in South Africa, and came to Philadelphia in 1993 as part of a pride of four lions, an adult male and three females. She wasn't a dominant personality, but she soothed her family, her keeper said.
"When we were first teaching them to move out into the exhibit and then back to home base, the adult male would be slow to make a move," Buffamonte said. "I would ask her to go out and pick him up, and she always would. She was always really about the family."
It was Zenda and her pride that helped pioneer Zoo360 - the zoo's trail and transfer system, which allows animals to roam more freely.
Zenda and family "were quite confident and calm and highly enriched" by exploring the zoo at will, Buffamonte said. "She was interested to see people in different ways. She was a pioneer."
She was a staff favorite, too. If she saw zoo employees she knew who worked in administrative offices nearing her exhibit, she would go to the front of the exhibit and travel with them.
"There were several staff members over the years who said that she was their favorite," Buffamonte said.
Zenda was temporarily relocated to the Columbus Zoo in 2004 before returning to Philadelphia when the Big Cat Falls exhibit opened in 2006.
The typical zoo lion lives to be about 17; Zenda's age alone made her remarkable.
Zenda's advanced years won her some perks - she had her own air conditioner, heater, and fan. Rather than being incorporated into a new pride after her family died off, Zenda lived alone in an area near the keepers. She went outside if the weather was nice.
"And she had a voracious appetite until yesterday morning," Buffamonte said Friday. "She loved to eat."
Personally, Buffamonte will miss Zenda, who was trained to participate in her own medical care, voluntarily lying down for shots or to donate blood.
"Zenda might have flown under the radar because she was so calm and steady," Buffamonte said, "but she was very clear about who her keepers were."