Nancy's dinner is waiting for her in a wheelbarrow: about a hundred pounds of hay, a big bucket of horse chow, a mound of hydroponic oat sprouts, an orange, an apple, a bunch of bananas and six small loaves of Italian bread. It's enough to lure the 28- year-old, 10,000-pound African elephant in from her yard to a pre-dinner training demonstration.

Elephant-training demonstrations take place daily at 2 at the National Zoo's Elephant House. But on Elephant Day this Sunday, there'll be additional demonstrations plus films, an elephant draw-in, stories about elephants, slide shows, an elephant dance, an exhibit of elephant contraband and food from the lands of the elephants. The food will be for humans only, since elephants have to stick to their healthful vegetarian diet.

"Nancy used to be sick on Mondays before we stopped allowing the public to feed the elephants," says keeper-leader Jim Jones, who's been taking care of the zoo's elephants for 21 years and was there on the historic day that Nancy pushed her male roommate into the moat.

"We had to fill in part of the moat and build a ramp to get him out," says Jones, shaking his head with the grudging admiration of a parent for a naughty but bright child. The bull elephant has since gone to another zoo and Nancy's only elephant confreres are two Asian elephants she can only gaze at across the yard.

The zoo plans to change all that by renovating the elephant house, acquiring some new elephants and starting a breeding program. The breeding program will probably not mean putting another bull elephant in the Elephant House, however.

"Male elephants go into something called musth, which makes them extremely aggressive and difficult to handle," explains Ed Gould, curator of elephants and other mammals.

In the wild, elephants live in large herds dominated by what Gould calls "the alpha female" -- usually the oldest cow still capable of breeding. Female babies grow up and stay with the herd for life, but males leave when they're about six to lead a solitary bachelor existence. When they're about 14 and start going into musth, they rejoin the female herd for brief breeding honeymoons.

"We'll probably breed Shantih -- that's the young Asian elephant -- by sending her to a zoo that has a bull elephant," says Gould.

Shantih, who came to the zoo from an elephant orphanage in Sri Lanka in 1976, now shares quarters with Ambika, another female Asian elephant. They're both smaller than their African cousin, Nancy, and no one is quite sure how the three would get along. When the Elephant House renovation is completed sometime next year, the two kinds of elephants will have connecting yards.

"We'll have to get them acquainted very slowly," says Jones.

Since there are so few elephants, Jones and the other keepers supply needed social interaction, according to Gould.

"The keeper's role is analagous to that of the alpha female," says the curator. "They use the ankus -- the hook -- in the same way the alpha female uses her tusk."

Zoo visitors have often viewed the ankus -- and the chains used around the elephants' feet -- with alarm, and a volunteer takes pains to explain the necessity for them to spectators at the training session. The ankus is a symbol of authority and is used to stroke affectionately as well as to prod, says the volunteer, as Jones puts Nancy through her paces. Using short commands, he tells her to lie down, raise her trunk and raise each foot.

"He does that to check her feet," explains the volunteer. "A lot of elephants die in the wild because something happens to their feet. He also has to file her toenails regularly."

When Jones puts on the chains, Nancy doesn't seem to mind but some of the visitors do.

"We chain them regularly so that if we have to chain them -- for medical treatment, for example -- they'll be used to it," the volunteer tells the crowd.

Elephants are highly trainable but the zoo's aim is not to make them do circus tricks; rather, it's to make them easier to control, says Gould. He envisions the day when the zoo's mini-herd of elephants will move heavy equipment around the elephant yard -- in emulation of the elephant lumberjacks of India and Sri Lanka.

Does this mean elephants are highly intelligent?

Gould hedges, having recently conducted a seminar on animal intelligence in which every human participant touted the intelligence of his or her pet species.

"If living a long time and learning and remembering what you've learned means you're intelligent, elephants are very intelligent," he says.

Nancy, meanwhile, is giving a practical demonstration of elephant intelligence. She's picking the loaves of Italian bread out of the rest of her dinner and eating them first.

"She always looks for them," says Jones, with admiration bred of familiarity. ELEPHANT EVENTS --Besides the regular 2 o'clock elephant-training demonstration this Sunday, there'll be demonstrations at 12:30 and 5, plus films in the Education Building at 10, 10:15, noon, 1, 1:30 and 3:15. The zoo will supply materials for anyone who wants to draw, paint or sculpt an elephant from 10 to noon beside the elephant yards. At 11:30 and 12:30, docents from the Museum of African Art will tell elephant stories in the Elephant House, and the Eve Anderson Dancers will perform an elephant dance in the giraffe yards at 1:30 and 3. Thai food will be sold in Panda Plaza across from the elephant yards all day, and there'll be an exhibit of elephant contraband in the Education Building lobby. Everything except the food is free and all events will take place rain or shine.