The sun shone down upon Hickory Hill Saturday, and two by two, the animals and their owners came, as they do almost every year, to Ethel Kennedy's three-ring pet show.

Sheep dogs shook, poodles pranced, and reptiles . . . well, reptiles are reptiles. But the pet show was just one part of the afternoon, competing, with limited success, against the celebrity tennis match, the pony rides, the log walking, fishing games, and on and on. This was not lost on the pet judges.

"Talk about the tail wagging the dog," said columnist Philip Geyelin. He and fellow judges Art Buchwald and former HEW secretary Joseph Califano spent most of their time in the pet show ring, doling out prizes like ward heelers in an election year. Hardly anyone goes away disappointed. Except Bobby Kennedy Jr. and he's used to it by now.

Kennedy Jr. climbed into the ring for the most unusual pet competition holding a very large turtle under his arm. "Bobby Kennedy has been submitting this tuttle for 25 years," Buchwald told the crowd, "and he's never won." That didn't deter the ABC camera crew that trailed Kennedy and the turtle around the ring at close-up range.

The prize went to a python and a crab. "Too close to call," said Buchwald judiciously, "both of them get blue ribbons."

"Better luck next year," someone called out as Kennedy left the ring and unceremoniously deposited the turtle in a wire pen with some mangled watermelon rinds. "Booooo," said Kennedy.

"Mammals are out this year," said a man holding a plastic bag full of goldfish.

Over at the tennis court, Redskins quarterback Joe Theismann and Dick Dell played a relaxed doubles match with tennis pro Jim Delaney and TV anchorman Ted Koppel. The FAI's George Stevens Jr. made the calls. Delaney was bound for the French Open in just 24 hours, and the match didn't look like very good warm-up. "It's not," said sports lawyer Donald Dell, "I think he's just doing this to be nice."

Ethel Kennedy roamed the grounds, accompanied by pet show organizers and a few curious Kennedy watchers. "We'll raise about 25," Ethel Kennedy predicted. That's $25,000 -- for Runaway House. "It's all seed money for federal funds," Kennedy said. "That's what's nice about it." She set off toward the swimming pool. Back in the ring, her devoted judges did their duty.

"Will someone please escort Mr. Califano from the ring?" Buchwald shouted into the microphone. Califano, dressed in an "I Quit Smoking" T-shirt and a blue cap, exited slowly, patting puppies as he went. "Now stay," Buchwald commanded. "STAY!"

As the afternoon waned, Terry Cook, a blond woman dressed in a teery-cloth sunsuit, walked her ferret, Frito, to the shade of a large tree. Frito, slinking along the ground at the end of a thin black leash, narrowly avoided being flattened by a tennis shoe. "Squish," said the owner of the offending sneaker.

"I know, I know," said Cook wearily, "it's been incredible."