The otters balked. It was their first day in the National Zoo's new Beaver Valley, and they didn't want to leave.

They'd been cautious at first. The male fell in the pool and scrambled out, very frantic, causing a keeper to comment, "I know they're young animals, but they ought to know what water is like." By the end of the day, though, they were whipping their long bodies around the pool, past visitors watching through underwater windows. When an otter wasn't swimming, the other otter used teeth to yank it into the water by its ear.

All week the creatures have been moving into Beaver Valley, and by this Friday, the beavers, the timber wolves and the bush dog will have taken their places in the eight-care valley, along with the sea lions, gray seals and otters, for the official opening. The "new" Beaver Valley is the first major change in the Zoo since the Lion House was opened in '76.

Beaver Valley is cageless, as it was in the 1890s when "wild" beavers built dams there and the Zoo was just beginning. In 1909, ten wolf-and-fox cages went up, and now, 70 years later, the cages are gone and "natural environment" is back. The Zoo people hope the beavers will build a dam in their manmade home, complete with dead trees stuck upright in pipes and a rushing stream ("to get them going").

The sea lion pool, completed in 1910, and looking frumpy in recent years, has been replaced, by a modern 450,000-gallon amphitheater with windows for an underwater view.

Most of the kids are fascinated to look underwater. Turning to his mother, a pre-schooler asks one of those befuddling questions: "How does the water stay up?" But a toddler takes one look at the window and bursts into tears. To anyone who'll listen, the mother explains, "We had to leave the seals. They jumped in the water and he started screaming." Maybe it was a bad day.

The sea lions already have names: Rutherford (Rusty) and Norman, and Jennie, Maureen (their former keeper at Marineland in California), Pearl, Amber and Esther (Williams). They swim so fast the visitor has trouble counting them, let alone telling one sea lion from another. "They have to come up to breathe," a father explains. "I know, son replies. "But they do it in the corners where you can't see them."

One pool up, the gray seals are molting, a seasonal thing. Two mottled male beasts, Gunnar and Nyal, loll on their rocky beach. The female, Selkie, swims without stopping. Curator of aquatic mammals "and a few canids," Daryl Boness says the Navy sent the seals to the Zoo after they gave up trying to teach them anything. "The Navy was teaching them to use the front flippers manipulatively to open and close valves, and to take a long object and insert it in an opening. They weren't as trainable as sea lions," Boness says. "They aren't always food-motivated."

Up at the otters' stream, the keepers wouldn't let them be alone this first night. The otters might slip over the surrounding rocks and scurry away. The keepers were coaxing the otters from their den with food, and one keeper crawled into the den by another entrance and, wielding a net pole, scared them out from behind. At last, exactly as the keepers wanted, the more contrary otter darted into a box that had been "home" on the plane.

Escape is "something you come upon when you want to make a natural exhibit," says Mike Morgan, who's an information specialist at the zoo. So you have to keep watching the animals, to see what they try, and then patch up any escape routes you hadn't thought of. "You don't know until you put the animals in there, short of building an enclosure," says Morgan.

Well, what about those timber wolves? Can they get out? "We'll see," says Morgan.


Tours of Beaver Valley on the Polar Bear Trail will be held Saturday and Sunday from 4 to 7:30. Friends of the National Zoo will be on hand to answer questions and escort visitors through the filter room, the kennel area and the kitchen. CAPTION: Pictures 1 and 2, SEA LIONS REST BETWEEN DISPLAYS OF UNDERWATER EXPERTISE, AS FANS WAIT FOR THEM TO START SWIMMING AGAIN. Photos by James A. Parcell.