The neighbor was persistent: Why didn't Kenneth Clark follow "Civilisation" with a civilized look at animals and men in art? And, just incidentally, contribute some of the sale proceeds to the World Wildlife Fund?

"As a neighbor, it made it all very convenient," Fleur Cowles remembered with satisfaction. "Oh yes, he said he wouldn't do it at first. But there is what you call American persistence."

"There is also what you might call Fleur persuasiveness, which many have found a kind of irrestible force. The result if a new Lord Clark book, "Animals and Men," handsomely published to catch the Christmas art-book season, paired with 35 art exhibits at some of the leading museums around the world.

"The Animal in Art" opens today at the Hirshorn Museum, and it is a delight to both the eye and the spirit. There are Giacometti's hang-dog "Dog"; Picasso's playful "Little Owl," fashioned from screws, nails, and a small spade; and the Calder "Fish Mobile."

Yesterday Fleur Cowles was in Washington for the Hirshorn opening with a news tidbit about her neighbor to impart.

"Lord Clark is going to be married to a woman who lives in Northern France. I'm not free to give you her name.It has been published somewhere and denied, but it is true," Clark's London neighbor reported with relish.

And added: "There is still publishing ink in my veins."

Fleur Cowles (now the wife of Tom Montague Meyer, the British "Mr. Timber") started out as an advertising copywriter when she was 16.Then began a remarkable career as a fashion columnist, advertising executive, associate editor of Look magazine (she once was married to Gardner Cowles, of the publishing family), and finally, Flair, the magazine with the fold-out pages and the covers with holes.

Flair lasted only 13 months (it sold for 50 cents and cost $2 to produce back in the early '50s). But it is still remembered as a publishing classic: One Washington printer keeps the first and last issues in his shop vault.

"I'm not sorry it died," Fleur said yesterday. "I'm much more happy it has . . . Until I started painting, I wanted Flair to be my obituary. Now I want my paintings to be so."

The photographer was stationed to take her picture, and she reached for her dark glasses.

"This is my trademark. The dark glasses are me," she explained as he protested.

Lord Clark's first wife was ill when Cowles first suggested that he do a book on animals in art. As he notes in the forward, he didn't think it was such a good idea at first, "but on reflection it occurred to me that no one had ever given much thought to the relationships of animals and men, and this might be a subject worth exploring."

It proves worth exploring both in Lord Clark's book and the 35 exhibits in museums like the Prado in Madrid, the Topkapi in Instanbul, and the British Museum in London.

As at the Hirshhorn here, each museum is mounting its own show from its permanent collection and loans. The Topkapi has assembled miniature, bejeweled animal forms. In Lagos, Nigeria, the exhibits span 2,000 years of animal art in Africa.

The cave-paintings of Lascaux record man's first reactions to animals, the most important element in human life and survival at that primitive time.

"Through art, you can see when the animal was God. Then the animal became a token, later a decoration, and then man's best friend. At no time since first man painted and sculpted has the animal been missing from his art," Cowles pointed out.

Cowles plans to go out to the Washington Zoo on Sunday for the first of three "sketch-ins" for children. On three Sunday afternoons from 1 to 3 p.m. (this Sunday, Dec. 18 and Jan. 15), the zoo will supply drawing papers, pencils and masonite boards for the public to use.

Smithsonian has another show as part of its "Animal in Art" program in recognition of the conservation aims and work of the World Wildlife Fund. "Beyond the Ocean, Beneath a Leaf," an exhibit of 57 stunning dyetransfer color photographs of Kjell B. Sandved, will be on exhibit in the second-floor rotunda of the Natural History Museum. Both of the Hirshhorn and Natural History exhibits will continue through Jan. 15.