INQUIRER: Old age has claimed another animal at the Philadelphia Zoo. Twigga, who at 29 was one of the oldest giraffes in the nation, was euthanized Thursday at the zoo, her home since 1979. In announcing her death yesterday, the zoo said the giraffe — tall for a female at 15 feet — had been on medications for age-related arthritis for some time. “Based on Twigga’s comfort and behavior, the zoo’s veterinary team decided this week that humane euthanasia was now the best course for her,” the zoo’s statement said. Giraffes typically live into their late teens and early 20s. She is the second giraffe to be euthanized at the zoo this year. Puzzles, 27, was euthanized in March due to age-related problems. Earlier this month, Petal, then the oldest African zoo elephant in the nation at 52, died at the zoo. “The zoo has a lot of very old animals, and we’re coming up to the end of the life cycle for many of them,” said Kirsten Wilf, a zoo spokeswoman. MORE