Five baby penguins, legally obligated to be cute as pie, did not disappoint Saturday in San Francisco.

They did their adorableness thing in front of 1,000 penguin fans who had lined up an hour early at the San Francisco Zoo so as not to miss a single precious moment of the annual March of the Penguins.

“Awww,” said a whole lot of people, too many to count.

Baby penguins do not exactly march. They waddle, glide, flop, scamper and skedaddle. No marching.

“One, two, three, go!” penguin keeper Eva Mac Solano said as she opened a small cage holding the five 10-week-old birds, which immediately flew the coop and found themselves facing a shoulder-to-shoulder mob of passionate penguin fans.

All the humans had been warned to keep behind the white chalk lines. They had been warned not to touch the penguins as they passed by. Occasionally, those rules were observed. Faced with a temptation almost beyond human measure, it was awfully hard for a penguin fan to keep his or her head.

The penguin march happens every year when zookeepers introduce the babies to the main colony at the remodeled reflecting pool known as Penguin Island, which used to be known as Tuxedo Junction before keepers decided that the tuxedo thing, as it applies to penguins, was something of a slur.

This year the babies — two males and three females — were color-coded with tags. The one with the blue tag was Poppy. Red was Spartacus, yellow was J.P, black was Annabelle, and the zoo hasn’t figured out what to call the penguin with the orange tag yet.

While the penguins were on the move, Solano was one busy woman. She spent most of the time bent over, at penguin level, scampering alongside the birds to keep them together and to keep their adoring, cell phone-clicking fans at bay.

“It’s exhausting,” she said. “My thighs hurt. When this is over, I have to take Tylenol.”

Halfway down the march route, the penguin with the blue tag did what penguins and people often do, and all over the pavement. At that particular moment, few people were moved to say “aww.” But Glen Jacques, who came with his wife and two kids, was overcome.

“I never saw a penguin poop before,” he said. “That was exciting.”

While penguin fans waited behind the chalk lines for the birds to waddle their way, they threw ping pong balls through hoops to win penguin prizes and bought $5 name-the-penguin raffle tickets and munched $5 penguin sugar cookies.

The actual penguins do not get sugar cookies. They get herring spiked with vitamin tablets.

“A penguin is not supposed to eat sugar cookies,” said curator Anthony Augello.

On march day, the scent of penguin permeates and the excitement is palpable. The only exceptions Saturday came from a rhino and two otters in nearby enclosures that nonchalantly went about their affairs and ignored the fuss. The rhino keeper said the annual penguin march is a fine time to train the rhinos, because visitors were preoccupied with the penguins and there were fewer distractions.

It’s not particularly easy being a penguin parent, or any other kind. This spring, the flock of 46 penguins produced 38 eggs. About a dozen were infertile. Two dozen others failed to pass muster with the Maryland computer matchmaking service formally known as the Species Survival Plan of the American Zoological Association. The idea is to prevent inbreeding.

Shortly after being laid, the infertile and genetically inferior eggs were deftly replaced by keepers with wooden fakes. Penguin parents apparently cannot tell the difference. The zoo pulls the same switcheroo every year, and the penguin parents never wise up.

“We always keep a lot of fake penguin eggs on hand,” Augello said.

When the penguins were done marching past their fans, they passed through a small gate and plunged into the giant penguin pool. There, Augello said, they seem to have something of a better deal than the competing penguin flock that lives inside a smaller, indoor exhibit space at the California Academy of Sciences in Golden Gate Park.

No animal keeper speaks ill of a fellow animal keeper. Yet all seek to sell tickets. It’s a competitive market, and budget-conscious penguin fans must choose between visiting the zoo penguins, at $23 a ticket, and the academy ones, at $44.50 a ticket.

“Our penguins can swim around and around, and they come up and down like porpoises,” Augello said. “The academy ones can’t do that.”

Freelance writer Anna Rubenstein contributed to this report.

Steve Rubenstein is a San Francisco Chronicle staff writer. Email: srubenstein@sfchronicle.com Twitter: @SteveRubeSF