While the Zoo Atlanta community recovers from the loss of senior citizen gorilla Ivan, 50, who died Monday, they were reminded that the circle of life goes on with a bit of good news announced Tuesday.

Lulu, a western lowland gorilla and one of four children of the famous Willie B., is expecting a baby.

That infant, due in the spring of 2013, would be Lulu's first surviving child. She gave birth before, in 2005, but the baby failed to thrive and died five days later. Infant mortality among gorillas is usually about 25-30 percent.

The new arrival would be the 19th gorilla born at Zoo Atlanta, which has the largest collection of gorillas in North America.

Taz, a 23-year-old silverback with four adult female partners and seven offspring, is the father of the new baby. Lulu's child would join Macy Baby, 6, Gunther, 6, and Merry Leigh, 1, all of whom are also Willie B.'s grandchildren.

Zoo personnel learned of the pregnancy the same way that many Americans do: with a drugstore pregnancy test kit. "They have the same markers in their urine that humans have," said Dr. Hayley Murphy, director of veterinary services. "We are big consumers of Clearblue Easy test strips."

The keepers have been working with Lulu to train her to participate in ultrasound sessions so that they can monitor the progression of the pregnancy, but "she's not quite there yet," said Murphy. "If she wants to participate, she can."

Gorilla infants gestate for about the same length of time as human babies, but are born with less difficulty, said Murphy. Most gorilla newborns weigh 2 to 3 pounds and are born after about an hour of labor.

Lulu, who weighs about 167, may gain only 10 pounds during her pregnancy, Murphy added.