King Kong, who walks upright and stands twenty-five hairy feet off the ground, clings to the top of the Empire State Building with one arm and clutches a blonde, Fay Wray, with the other. Airplanes, all of which look much smaller than the great ape, strafe him from all sides.

"I think people who see the original, 1933 version of the movie come away with a great deal of smypathy for King Kong," says Bill Xanten, curator of mammals at the National Zoo. But not necessarily a clear understanding of what gorillas are really like, he adds.

"There was a gorilla species almost as big as King Kong, but it died out 500,000 years ago. A large male gorilla only weighs about 400 pounds. In the movie there were about ten people inside King Kong's gorilla suit. A gorilla could probably climb to the top of the Empire State Building, but he wouldn't be interested in Fay Wray unless she had a bunch of bananas on top of her head."

This Sunday, to point out the differences between real gorillas and King Kong, the zoo is inviting families to see the movie and then meet some real-life gorillas.

"Gorillas are shy and easily intimidated," says Melanie Bond, a keeper in the ape house. To illustrate the point, she takes a pair of sunglasses out of her pocket and shows them to Nikumba, affectionately known as Nikky. The gorilla backs quickly away from the glass partition.

"How's that for a contrast to King Kong?" says Bond. "Nikky is scared to death of a pair of sunglasses."

When the glasses are safely back in Bond's pocket, Nikky edges back toward the keeper and sticks out his lower lip.

"People think that's a pout, but it's really a smile," explains Bond. "When gorillas are unhappy they pull in their lips so tight that you can't see them."

Although Bond says that the sexual overtones of "King Kong" are unrealistic, she also says that gorillas do get attached to humans; and they have their own individual likes and dislikes. Nikky, for example, likes Bond but does not like Xanten.

"He always used to spit at Bill," says Bond. "But he's not doing it now.I think it must be the new quarters."

Nikky, his mate, Femelle, and another gorilla couple, Tomoka and Mwasi, have already moved into the zoo's new ape house, which they will share with four orangutans. The ape house is not yet open to the public, but families who attend Sunday's event will get a preview tour. In the new quarters there are concrete trees for the apes to climb and places for them to hide and ropes for them to swing on. For the first time, the two gorilla pairs can watch each other.

"Our aim is to build a social group," says Xanten. "But we have to go slowly and play it by ear. We have to work with the gorillas we have, and they weren't raised that way."

In the wild, gorillas live in troops with one lead male and a lot of powerful matriarchs. Scientists think that gorillas in this sort of social group might be better at breeding and raising their young themselves. This is the trend in zoo-keeping. Another trend is toward specialization. In keeping with that trend, the National Zoo is concentrating on gorilla and orangutan breeding.The zoo recently traded its one chimpanzee, Ham, to a zoo in North Carolina.

"Ham is doing surprisingly well," says Xanten. "He's the famous chimp who flew in space, and because of the demands of the space program he was kept isolated and raised by humans. Now he's with a female and is part of a social group of chimps."

The first step in setting up a social group of gorillas at the National Zoo would be to introduce the two pairs of apes. But officials plan to move cautiously.

"We may just put the two females together at first and see how they react," says Bond.

Meanwhile, the two couples are getting used to their spacious, neighboring digs in the new ape house. Nikky and Femelle are swinging on the ropes and climbing the concrete trees, but not yet bouncing on the branches.

"They probably don't trust them yet," explains Bond.

Mwasi has turned a plastic dishpan into a boat and is floating it on a mini-waterhole. Bored with that, she wanders off to find Tomoka, who is sitting out of the viewing area in a place designed to satisfy the gorilla need for privacy.

"Honey, I'm home," apes Bond, as Mwasi climbs up to be with Tomoka, who may or may not be her mate. "Tomoka was the first non-human to be diagnosed as having rheumatoid arthritis. We think he's all right now, so we got Mwasi as a wife for him. She's a good companion, but we don't know if there's anything else. But he's glad to see her. I can't hear him through the glass, but see how both his lips are curling out. He's making his pleasure grumble."

It's the female gorilla, according to Bond, who has to initiate sexual activity.

"If the male doesn't get the right signals from her, he'll be content to be his old celibate self," she explains.

To prevent that, Bond encourages any sign of gorilla affection.

"Hug femelle," she tells Nikky, communicating with him through the glass with sign language. When Nikky obliges by patting the female on the shoulder, then pinching her on the rear, Bond is very pleased.

"Good boy," she signs to Nikky, then tells a visitor: "I think these new quarters are very good for Nikky. He would never have made an affectionate gesture in front of a stranger in the old ape house."