Three female elephants, Kamala, Swarna, and Maharani, will be transferred to the National Zoo in Washington in the spring of 2014. (Bill Quayle/Calgary Zoo)

The National Zoo is getting three new Asian elephants, boosting the size of its herd to seven and more than doubling the number of elephants it had just three months ago, officials said Tuesday.

The three female elephants will be coming from the Calgary Zoo in Canada, but not until spring. They will further populate the National Zoo’s new elephant complex and provide a laboratory for the study of elephant life and society.

The news comes on the heels of the zoo’s acquisition in May of Bozie, a female elephant from the zoo in Baton Rouge, La., that brought the herd then to four.

The Calgary Zoo announced last year that it was closing its elephant exhibit because of its cold climate, its inability to expand and its desire to give its elephants the benefits of living in larger herds.

In June, the Calgary Zoo, part of which sits on an island in the Bow River, was devastated by flooding. Two hippos almost escaped from the zoo. The elephants stood in two feet of water, and the zoo suffered $50 million in damage.

Much of the zoo, including its elephant exhibit, remains closed. But the decision to relocate its elephants had been made before the flood, officials said.

The Washington-bound elephants are Kamala, 38, Swarna, 38, and Maharani, 23.

They will join the National Zoo’s females, Bozie, 37, Ambika, 65 — the second oldest Asian elephant in the country — and Shanthi, 38. The zoo also has a male, Kandula, 11.

But a bigger herd means more mouths to feed.

The zoo offers each elephant about 200 pounds of hay a day, Director Dennis Kelly said. That means daily consumption could go from about 800 pounds a day to 1,400 pounds day. Fortunately, he said, the zoo grows its own hay.

The Calgary Zoo said in a statement that it will retain ownership of its elephants “for a period of time to ensure that their long-term needs continue to be met.” Kelly said that the transfer is likely to later become permanent. “Calgary has no intention of taking them back,” he said.

David Rubenstein, a Washington philanthropist who has been a major National Zoo benefactor, is providing $2 million for the transfer, officials said. That will pay for, among other things: transportation, keepers’ travel, veterinary assessment and upgrades to the facility to accommodate the new tenants.

The Calgary Zoo’s male elephant, Ganesh, nicknamed Spike, is being sent to Busch Gardens in Tampa.

The acquisition of the new elephants is the latest step in the National Zoo’s push to become a state-of-the-art center for elephant research and home to a large Asian elephant herd. Asian elephants are endangered.

“It is completely in line with our strategic and scientific plan to grow a long-term, stable, matriarchal herd,” Kelly said. “We’ll see some aspects of this herd at the National Zoo 100 years from now.”

In March, the zoo opened a new elephant community center, which resembles a sunny, indoor elephant sandbox.

It was the second phase of the zoo’s $56 million Elephant Trails exhibit.

The first part, which included a 5,700-square-foot barn, two new yards, a pool and a quarter-mile walkway through woods, opened in 2010.

The zoo can now accommodate at least 10 elephants.

“Once we made the commitment to Asian elephants and to renovate the facility, building a bigger facility, we knew that we needed to increase the size of our herd,” said Brandie Smith, the National Zoo’s senior curator.

“And one of our top priorities has been to bring more elephants to the National Zoo,” she said. The Washington zoo knew that Calgary was seeking homes for its elephants, and a deal was struck.

“We are so excited,” she said. “These three girls are absolutely wonderful elephants. ”

Maharani is of breeding age. Last fall, she delivered a stillborn premature calf. She has had two other pregnancies, but neither of the calves survived.

Smith said one goal would be to get her pregnant again.

“The best thing for her welfare . . . is for her to have a baby, and then have that baby be taken care of by the other elephants in the herd,” she said.

Kamala, the Calgary group’s matriarch, was born in 1975 in Sri Lanka’s Yala National Park. Orphaned at 6 months, she was found at the bottom of an abandoned well by park staff. Her name is Hindi for Lotus Flower. She was brought from the Pinnawala elephant orphanage in central Sri Lanka to Calgary in 1976.

Maharani, who was born in Calgary in 1990, is Kamala’s daughter.

Swarna also came to the Calgary Zoo in 1976 from the Pinnawala orphanage.

Smith said she was not sure how the elephants would be transported to Washington. It’s a 2,300-mile road trip from Calgary to Washington. In May, Bozie made the 1,100-mile journey from the Baton Rouge zoo by truck.

“We can drive them,” Smith said. “We can fly them. There are various ways we can get them here.” She said keepers from Washington will first visit Calgary to get to know the elephants.

Smith said all six female elephants will eventually be kept together. The male is kept separately. Smith said an extra keeper will be brought in to keep tabs on everybody.

She said the elephants will figure out who will serve as the new matriarch. Ambika is the current matriarch, but Bozie has recently been asserting herself.

“The elephants will basically tell us what the structure of the herd is going to be,” Smith said. “We do expect there will be some conversations between the elephants to determine” that.

“There’s a dominance hierarchy in an elephant herd, and the elephants are going to work that out,” she said. “What we will do is give them the right space and all the right resources so that they can figure out what that social structure will be.”

She said the zoo might add some more feeding stations throughout the exhibit to avoid quarrels over food or treats. “We don’t want any reason for them to fight with each other or argue with each other,” she said.

She said she did not know whether elephants develop hurt feelings over social rearrangements, but the zoo would be studying the new dynamic.

She added that Bozie, Shanthi, Swarna and Kamala were all once in the Pinnawala orphanage together. Smith said she did not know whether they would remember one other, but that, too, could be a focus of study.

“It’s just really exciting that these girls are going to get to be together again,” she said.