Los Angeles ? Regina and Renata Salinas Fierros lay in side-by-side beds for the first time in their 10-month-old lives Thursday after doctors separated and rebuilt the twins’ bodies in a marathon surgery.

“To see the girls today beginning to wake up and move and respond is great excitement for us all,” lead surgeon Dr. James Stein said at a news conference.

While Renata was the sleepier of the pair, Regina moved an arm, doctors reported.

“She was the feistier of the two,” said Dr. William McIlvaine.

The girls were born facing each other, joined from the lower chest to the pelvis. They were fused in several places, including the liver and genitals. They shared a large intestine, and Regina was born with one kidney.

The operation began at 6 a.m. Wednesday, and the reconstructive surgery ended about 4 a.m. Thursday, two hours earlier than doctors had anticipated.

Doctors made an incision at the breastbone and then divided the internal organs.