The fastest thing on four feet, and never mind all that guff about the cheetah that people have been accepting for years, is a handsome animal named Copelan.

And unless the sun comes up in the west today, he'll run away with the 1 1/8-mile Florida Derby (WJLA-TV-7 at 5:36 p.m.). It is the general belief around here that Copelan has all the necessary credentials to set his own pace, dare anything to catch him and become the favorite to win the Kentucky Derby, come May 7.

That may be a lot to live up to, but Copelan has a wonderful resume. It wasn't until the seventh race of his career that any horse finished in front of him. And in his latest exhibition of speed he made a cake-walk of Gulf Stream's Fountain of Youth Stakes, against several of the same steeds who will try to beat him today.

The lucky gentleman who owns this speedball is one of the most respected in racing. He is Fred W. Hooper, who is 85 years old, is still taller than Bowie Kuhn, likes to help out a little bit with the training of his horses and in 1946 won the Kentucky Derby with the first horse he ever owned. Name of Hoops Jr.

In today's classic, previously won by such notables as Carry Back, Northern Dancer, Alydar and Spectacular Bid, there will be a field of 12 3-year-olds. But with a nod to Shakespeare, the oddsmakers are saying that the cast is comprised of one principal and 11 spearcarriers.

The only reservation about Copelan is whether he can carry his speed 1 1/8 miles, which is farther than he has ever gone before. He gets good stamina from his dam, Susan's Girl, and her sire, Quadrangle. But the suspect in his genes may be his sire, Tri-Jet, not noted for distance.

Hooper didn't have to bid a nickle for Copelan, now a multimillion-dollar baby. He bred him from racing blood in his own barns. "Even as a foal he looked sound and smooth to me," Hooper said.

Copelan is a good-looking bay, but not quite what the horsemen call a thing of beauty. Breeder David Goldman said, "He wouldn't stop you in your tracks, like those good-lookers like Majestic Prince or Secretariat. I'd say he looks more like an Alydar. He's a good size but he doesn't carry much flesh. He runs like he enjoys it, though."

On the way to finishing first in eight of his first 10 starts, there have been a couple of misadventures for Copelan. The last was a terrible fifth-place finish in the Hollywood Futurity, his final race as a 2-year-old. Went to the post the favorite over Roving Boy.

Trainer Griffin Mitchell said, "Early in the race something kicked up a clod of dirt into his eye and my colt wanted no more of the race. I don't blame him. He had a bad-looking eye at the finish. The scar tissue is still there." The other race he lost was at the Meadowlands in New Jersey. "He wasn't himself that night," said jockey J.D. Bailey. "First time he ever raced under the lights and it shook him, I think."

Bailey, who rode Copelan in six of eight winning races, won't ride him today. They've switched to the more stylish Laffit Pincay Jr., who saw Copelan home in the Fountain of Youth. As most horsemen would say, "You don't ride anybody else if you can get a Lafitt Pincay."

Copelan drew No. 6 post position, in the middle of the 12-horse field. But post position is no big deal for him. In winning the Fountain of Youth, Pincay took Copelan from the most outside post and after barely a sixteenth of a mile had his eager animal five lengths in front, going into the first turn. All of Gulfstream gasped at that incredible early speed, and what he was showing at the finish.

Actually, Copelan was headed by a neck or so in mid-stretch by Currant Hope, one of those he'll face today, but it was almost as if Pincay deliberately wanted to test his mount. Yet without laying a whip on Copelan, merely by letting his hands give the message, Pincay got a response that took him to the wire, 2 1/2 lengths in front.

Chumming probably will be today's second choice. He is princely bred, by Alleged out of a Sea Bird mare, which is double royalty. Chumming ran a smashing race in the Fountain of Youth to be beaten two necks by runner-up Highland Park, but was a full second slower than Copelan.