They live in a habitat of soft red dirt, warm water and rock walls, but Zoo Atlanta still has to prepare for the thump-thunk of giant baby feet next year.

That's right: They're baby-proofing for elephants. Construction is just the latest change for mama Dottie since news of her pregnancy. The elephant's diet changed and ultrasounds are a regular activity. All three of the zoo's African elephants are stuck inside while their yard is made safe for the little bundle of joy, due in April 2009.

JAMIE GUMBRECHT/AJC (ENLARGE)

Zoo Atlanta expects Dottie (left) to deliver a calf in April, so staffers are baby-proofing the elephants' enclosure with features such as the lowest crossbar on this gate.

JAMIE GUMBRECHT/AJC (ENLARGE)

Heavy equipment is used to prepare the elephant enclosure for Dottie's baby, which will be about 3 feet tall. Zoo officials estimate baby-proofing will cost hundreds of thousands of dollars.

• More photos of Zoo Atlanta's baby-proofing work BABY FEVER Dottie's baby is due April 2009, but other Zoo Atlanta animals have kept vets busy -- including three different types of babies born on one day in April. Here are some of the zoo's recent additions. • May 31: Three African lion cubs • April 16: Two black-and-white ruffed lemurs • April 16: Two Argus pheasant chicks • April 16: One warthog piglet named Georgia P • Feb. 21: One milky eagle owl chick LIVING Latest Headlines: [an error occurred while processing this directive] • More Living Stories • Living photo galleries • Georgia Aquarium news and photos • Zoo Atlanta news and photos

Dottie and the calf's elephant aunties, Tara and Kelly, all will have a hand (trunk?) in keeping the baby safe, says Adam Stone, Zoo Atlanta's assistant curator for large mammals.

But even without cabinet doors and electrical sockets to worry about, young elephants like to climb and explore well before they've mastered the use of their limbs and trunk.

"They're in 9 million directions at once, wiggling and climbing," Stone says.

Baby-proofing a habitat is like baby-proofing a nursery, but bigger, requiring a team of construction workers in hard hats and Bobcats. They weld metal bars to any space that a 300-pound elephant could slip through, drain the pool to make it more shallow and add 800,000 pounds of dirt to the habitat.

They've cut out the steep hills, filled the moat around the yard and plan to cover a gated area that will give them all more privacy.

Construction should be done by October. Stone estimated baby-proofing will cost hundreds of thousands.

"Well worth it and necessary to create a safe environment for one of the biggest babies we'll ever have," he says.

Right now, the calf is about 20 pounds and the size of a football. When it's born, it will be about 3 feet tall and 250 to 300 pounds.

As soon as mom and baby are up and healthy, they'll be introduced to visitors.

Dottie is a 25-year-old first-time mother who came to the zoo in November 1986. She's the goofball, the big one who doesn't know her own strength. If the elephants were fairy-tale dwarves, Kelly would be Doc, Tara would be Sleepy and Dottie would be Dopey. (The zoo, by the way, says she will be a great mama.)

The 60,000-calorie-a-day meal plan is something like the elephant version of the South Beach diet — more bamboo and celery, fewer sweet potatoes and alfalfa, the cotton candy of the elephant diet.

Dottie is 12 months into her pregnancy with no morning sickness, no swollen ankles, not even a mood swing. She's actually lost about 300 pounds since the start of her pregnancy. Not to worry, though; she'll add about 600 by the end of the 22-month gestation period. By then, the calf's movements will be visible to onlookers.

They keep looking for subtle changes, like the slight development in her mammaries. But for all the talk and preparation, Dottie mostly seems interested in bamboo and carrots.

"We don't even know if she knows she's pregnant," Stone says with a sigh.