Happy, the National Zoo's solitary male Nile hippopotamus, is heading for the chillier climes of the Milwaukee County Zoo, officials said.  But no worries: His new digs there will include a pool, a sandy beach and two female hippos, Puddles and Patty.

His new name is going to be "Happier," one zoo official here joked.  Happy, who is 27 and weighs about 7,000 pounds, has lived his whole life at the National Zoo but has to leave because the expansion of the zoo's elephant exhibit, now well under way, will be claiming his quarters.

He is expected to be moved this summer. The Milwaukee zoo, meanwhile, is beginning a roughly $10 million expansion of its hippopotamus exhibit, part of which will allow visitors to watch hippos swimming underwater.

"We're totally excited," said Jennifer Diliberti, a spokeswoman for the Milwaukee zoo. Happy should be, too. Expectations are that there might soon be baby hippos, she said.  Pamela Baker-Masson, a spokeswoman for the National Zoo, said Happy's departure is "very hard for the zoo on many levels. We feel strongly about Happy. . . . But we know that Milwaukee is going to offer him a great life. There will be females for Happy. There will be a new facility.

"All of us deep down hope that it's not the end of Nile hippos for the National Zoo," she said. "At some point in our future, if there's a way for us to build a facility for them, they will come back to the National Zoo."  But for now it's farewell.  "We're saying goodbye to Happy," she said. "But it's for all the right reasons."