The monkey-shaped ceramic jug has all the impudence and wit of the creature and an elaborate pendant necklace to boot. If you blow across the jug's mouth, it makes monkey noises.

Almost anyone would love it on sight and want it for a pet. But you can't test the sound effects: The jug is locked in a glass case in the International Monetary Fund's Visitors' Center with others of its ilk, formally called zoomorphic bottles. Other jugs are shaped into a serious-looking owl and an unidentified sharp-faced creature. All of them are from Chorrera, a coastal region of pre-Columbian Ecuador.

The jugs are a part of a rare pre-Columbian show of 61 ceramic objects and three more of stone from Ecuador at the IMF Center at 700 19th St. NW, through Feb. 26. The art works, laid out in the simplest, most unassuming manner, span more than 4,000 years of Ecuador's history, which goes back to 10,000 B.C.

The jugs, bowls, figures, urns and such are small in size as well as number. Some were made as ceremonial or funerary vessels. Others may have been household objects to be used and to amuse. All are technically very advanced, some with thin walls, others constructed with hollows, several with different colors baked into the clay.

The objects have been hailed as "seldom seen, rarely displayed, marvelous stuff" by Gordon McEwan, assistant curator for pre-Columbian Art at Dumbarton Oaks. Betty Meggers, Smithsonian anthropologist and author of a definitive work on Ecuadorian art, said the works "greatly expand our knowledge and help to reconstruct the dress and the ornaments of the upperclass people of the period."

Ecuador, washed by the Pacific crosscurrents, produced great travelers and merchants, spreading their culture as they went. And Meggers sees distinct similarities in Mexican work.

Obviously, every object in the exhibit was made with pleasure and, sometimes, genius by highly skilled artists. And it's notable that these creative ancient people were well aware that art can be witty and humorous while still being serious, sophisticated work.

The bottles come in many forms. From the Chorrera comes a bottle shaped like a round house with a cone-shaped roof and a strange dome and spout. Another bears the shape of a merchant, his cheek stuffed with coca leaves to console himself for the heavy load suspended from his forehead by a tumpline. Another coquero, or coca-leaf chewer, is shown resting from his labors in the highlands with a plug of leaves bulging his cheek. The leaves, from which cocaine is made, were used as drugs even then to help workers in the high altitudes.

The musicians seem to have had all the fun. One happy drummer (also a vase) from Jama-Coaque (a coastal chiefdom) has a glass of chicha. Another musician from the same culture has not only birds but fruit and a serpent on his head. One wonders how he could keep his mind on his music. A Chorera musician has a wonderful panpipe almost as big as he is and a chorus of birds singing on his headdress.

One of the pieces, a flute or octorina, comes along with handsome painted decorations. A popular quipa musical instrument, made from a mollusk, was reproduced in ceramic with the same shell shape on the inside.

Another Jama-Coaque vase is also a man plucking out his whiskers. Two Chorrera vases are disembodied legs. A priest wears a wonderful headdress like five and 20 blackbirds baked in a pie and a poncho of seashells.

A few are more frightening. A feline head, with whiskers and fangs and a tongue to lick you up, is a deity from La Tolita. A trophy head represents a skull, hollowed out by a conqueror, seeking the soul.

A woman figure from Carchi in the highlands, though she's bare chested, sits in a modest ankle-length skirt. Another woman figure from the Manteno culture on the southern coast, where women were sometimes chiefs, has a skirt as short as people with good legs wear today, a handsome choker necklace and a highly ornamented band, like a ribbon of office.

One warrior figure from Jama-Coaque is really dressed up with a headdress, earplugs, nose ring, collar necklace, nipple and naval ornaments and a sort of a G-string. He also is equipped with a dart thrower and two other weapons.

The bowls and urns are handsomely ornamented with stripes and more intricate geometric decorations. Some are decorated with "negative" or "reverse" figures, where the ornament is covered with wax to keep the natural clay shade and the background is colored, a process like batik-dyed cloth.

The collection was lent to the Ecuadorean Embassy here by Quito's Museo del Banco Central, something like the U.S. Federal Reserve Board. The embassy, in turn, hopes to lend it to museums and universities around the country. The objects are a minute part of 13,500 pieces said to have been removed from Ecuador surreptitiously and illegally. They were returned in 1983 to Ecuador by the Italian government after years of litigation. A small number were exhibited at the Organization of American States in 1984.

The Ecuadorean Ambassador Mario Ribadeniera, at the recent opening of the exhibit, noted that his countrymen were making such marvelous works of art "before the Egyptians built the pyramids."

The exhibit may leave visitors wanting to know more, for the captions are sparse and the objects undated. Mario Leon-Meneses, Ecuador Embassy cultural counselor, says that until more research is done, the dating is in very broad periods.

Going to see the exhibit through its ceremonial entrance courtyard almost gives one the feeling of going down into a treasure cave. The subterranean IMF center itself is a buried treasure, known only to a few fortunate people, though it opened in 1986. Its changing exhibitions, seminars, cultural events, forums and films are open to the public.