20 gentoo penguins arrive at Detroit Zoo via FedEx Imagine: You're put on a plane while inside a 4-by-4-foot crate with a block of ice, then flown from San Diego to Memphis to Detroit. OOOH! But that's first class -- for a penguin.

Elissa Robinson | Detroit Free Press

Show Caption Hide Caption New gentoo penguins arrive at the Detroit Zoo New gentoo penguins arrive at the Detroit Zoo

Millions of special deliveries were made during the month of December, but a special package received by the Detroit Zoo — 20 gentoo penguins shipped via FedEx — may top them all.

The aquatic birds — 10 females and 10 males — were shipped from the SeaWorld aquarium in San Diego, according to the Detroit Zoo.

The newest flock of birds joined three other gentoos — the first of their species to arrive at the Zoo nearly a year ago — as well as the colony of king, rockhopper and macaroni penguins.

The news comes as the Polk Penguin Conservation Center (PPCC) nears completion. When the PPCC debuts in April 2016, it will be the largest penguin facility in the world at 33,000 square feet.

“Gentoo penguins are fast swimmers and divers and spend a lot of time in the water, so their new aquatic habitat will be an ideal environment for them,” said Scott Carter, Detroit Zoological Society chief life sciences officer.

The new gentoos are being held in a special quarantine area of the Penguinarium. Once the PPCC opens, they will move into their new home and the Penguinarium will be turned into a bat conservation center.

They were shipped in 4-by-4-foot plastic crates, punched with air holes and fitted with a block of ice on the bottom, said Tom Schneider, curator of birds at the Detroit Zoo. Two zookeepers from Detroit flew out to SeaWorld beforehand, helped plan the shipment, “and then they flew back with the penguins,” Schneider said.

Unlike larger zoo beasts in transit, the perky little penguins required no sedation, he said. Packed in five to a crate, “they all knew each other, so they weren’t stressed about that,” Schneider said. The birds handled the 13-hour trip, including a layover in Memphis, “with no problem. — all were all eating the next day,” he said.

The 20 gentoos were bred in captivity in California, Schneider added. “Now, SeaWorld has room to breed more — they do a really good job with penguins — and I fully expect to raise gentoos here (in Detroit) in the future,” he said.

The zoo’s new penguin habitat began with the largest private gift in the Detroit Zoo’s history — $10 million given by Stephen Polk, the Bloomfield Hills heir to an auto-supply fortune. The final cost, to be about $30 million, is building an icy habitat where penguins will deep-dive through a tower of water.

Zoo Director Ron Kagan has said the exhibit will constitute “a world-class attraction” that will boost zoo attendance and revenues, in part because penguins —through their real-life antics as well as by starring in animated films — are one of the world’s most popular creatures.

In addition, the exhibit aims to educate the public about the polar region’s rugged, yet fragile environment and about the effects of climate change on it. Stepping inside, visitors will be met with mock gale-force winds and simulated snow while serenaded with a chorus of penguin calls. The birds habitat is to be held at a permanent, chilly 37 degrees.

The exterior of the building will be in the shape of a giant iceberg of the typical shape, called tabular, for its cliff-like sides and top. Far less common is the storied iceberg shape, popularized in film and literature, of a vertical dome or spire of ice.

“We believe this will be the world’s most significant center for penguin conservation and education,” Kagan said last year.

Gentoo facts

■ The gentoo penguin is the fastest underwater swimming penguin, reaching speeds of up to 22 m.p.h.

■ Recognized by white stripe extending across its head and bright red-orange bill

■ The gentoo is the third-largest penguin, reaching a height of up to 30 inches and a weight of up to 20 pounds.