WASHINGTON – Happy the hippopotamus placed his right foot on the threshold of the giant moving crate and paused.

He peered warily at his keeper standing at the other end trying to coax him with a bucket of bananas.

“C’mon, Happy,” said the keeper, John Taylor. “C’mon. You’re not going anywhere today.” Happy wasn’t buying it. He gave Taylor a suspicious look and backed away.

Happy may not be going anywhere right now. But the National Zoo’s lone Nile hippo, who was born and has lived his whole life there, will probably be moving this summer to the Milwaukee County Zoo.

Curators are pondering: How do you move a 5,500-pound hippopotamus 800 miles?

First, you’ve got to get him in his timber and steel moving crate. And that takes practice.

There’s also the size of the crate. Zoo curators think the one they have might not be wide enough for Happy.

Then there’s the size of the truck – the journey will be a kind of hippo road trip, Happy’s first.

And there’s the size of the crane it will take to hoist him out of his yard. That task will be delicate because the crate should be kept perfectly level, curators said.

“We want the crate to be as stable as possible, as if it’s levitating,” said National Zoo Senior Curator Brandie Smith.

Happy has to leave Washington because the National Zoo’s expansion of its elephant exhibit will claim his quarters. And the Milwaukee zoo wants to expand its hippo presence and possibly breed Happy, who is 28.

Zoo officials plan to map out the best route to Milwaukee, as well as two alternates. They will also alert zoos along the way to have veterinarians on standby.

Happy will probably be traveling in an air-conditioned truck to ward off summer heat. The trip will take most of a day. The zoo plans to have plenty of food and water for the journey and lots of pre-trip practice.

If all goes as planned, he will join Milwaukee’s two female hippos, Puddles and Patty, in a swanky multimillion-dollar exhibit.

Taylor, who has been Happy’s keeper for 15 years, practiced getting him into the crate Wednesday. The zoo has had the crate in Happy’s enclosure for months. Keepers must gradually get him used to having one end closed, then both ends closed.

“We make getting into the crate fun,” Smith said.

Food is the key.

On Wednesday, Taylor placed a bundle of alfalfa at the closed end of the cage.

Taylor then enticed Happy toward the entrance with banana and apple chunks.

Taylor spoke soothingly as he coaxed the animal toward the crate.

“Come here, Hap, come on,” he said, lobbing food. “You like that, don’t you? You eat all your hay, now?”

Taylor banged the bucket on the crate. “You’re thinking about it,” he called. Eventually the lure of the alfalfa was too much, and Happy ambled in.

Taylor said he will miss Happy. He’s not sure the hippo will feel the same.

“I think he’s going to forget about me after the first day,” he said. “That’s my biggest fear. Because they’re going to have two ladies down there.”