Litsemba, right, who is 11 months pregnant with her third offspring, romps in the sun in the Expedition Tanzania exhibit with Sundzu, her 2-year-old, at the Reid Park Zoo. She’s expected to give birth between June and August 2014.

Mike Christy / Arizona Daily Star

A 250-pound bundle of joy is expected to make its debut at Reid Park Zoo next year when Litsemba, one of the zoo’s African elephants, gives birth to her third calf, and the first ever born at the Tucson zoo.

The 24-year-old elephant, known by her nickname Semba, her two calves, her mate Mabu and Lungile, an unrelated elephant, were brought to Tucson from the San Diego Zoo Safari Park in early 2012.

Keepers observed Semba and Mabu breeding in mid-October.

“It was like a giant elephant party,” said Sue Tygielski, zoo supervisor and elephant manager. “Semba would run in front of the bull with her tail up and she would trumpet and make lots of noise and get him interested and then he would start following her and the two of them would run around the yard and the kids of course would follow Mom.”

Lungile, who’s like an aunt to the calves, joined the rest of the herd so all five elephants were running around and vocalizing, Tygielski said.

All the activity would ultimately end in a breeding session between Semba and Mabu, followed by a few hours of rest and then everything started all over again, for three days straight.

Several months worth of samples of Semba’s urine was sent to a lab for analysis and last week keepers got confirmation of what they already suspected.

“Everyone is congratulating us and … it is very exciting but we’ve also had this gut feeling ourselves that she was pregnant,” Tygielski said.

Semba is about halfway through her 22- to 23-month gestation period and her calf is expected to be born between June and August 2014, said zoo spokeswoman Vivian VanPeenen.

Throughout her pregnancy, Semba will continue to be on exhibit and keepers are taking extra care in monitoring her health and making sure she gets enough exercise, Tygielski said.

That’s an easy task as 7-year-old Punga and 2½-year-old Sundzu keep their mom on the go.

“Her kids encourage her to play and to move around and get in the pool and swim,” Tygielski said.

Keepers are also keeping an eye on Sundzu as he makes the transition from baby to big brother.

“Once the new baby comes he’ll be kind of pushed off to play with the other calf and other herd members,” Tygielski said. “It’s a transition for everybody. But, he loves playing with his aunt already and his big brother so I don’t think it will be too bad .”