John Cleese developed his first crush on a lemur as a lovesick teenager in England. Attending the rigorous Bristol School, he would sneak over to the zoo across the street between classes.

"I used to watch a ring-tailed lemur, the cutest creature," Cleese almost whispered. "They're immensely good-natured and -- don't let Dave (Bocian) the keeper hear this -- not very bright."

The comic actor appeared at the San Francisco Zoo on Sunday for an informal ceremony to welcome the first lemur to its newly built, 3-acre habitat.

Cleese had flown on his own dime from Santa Barbara to help goose the publicity for the zoo's new habitat, and also to speak of the plight of endangered lemurs on the island of Madagascar.

The celebrity's only request: to have some quality time with the zoo's lemurs, which include animals with names like Belushi, Fang and Nozee Boy.

The Lipman Family Lemur Forest opens to the public on June 29. It is part of the zoo's renovation efforts, which also include a new entrance on Great Highway, a concourse with a new cafe and gift shop, art installations and the restored Dentzel Carousel.

But perhaps more important, the new lemur habitat signals the zoo's future vision as a conservation zoo, one that combines naturalistic habitat with innovative, animal-friendly ways to bring people and animals together.

Cleese, co-creator of the legendary "Monty Python's Flying Circus," tried his level best to keep these serious issues in mind.

Dressed in a spotless Navy blue blazer, buttoned-down white shirt and red tie, the tall actor had all the markings of a target. But he entered the lemur's existing habitat with amazing nonchalance.

"I don't know if anyone has ever tried to raise one as a pet, because quite literally, they have no control over their bowels," he said. "But there's a sweetness about them."

He was unshaken when a group of ruffed lemurs suddenly roared with a ferocity that startled those unfamiliar with the seemingly adorable creatures.

"C'mon," he said, shaking a bowl of food at a gang of eight.

In the wild, lemurs eat berries, leaves and insects. At the zoo, they are fed "monkey biscuits" -- a balanced, nutritional kibble. For this special event, they were offered fresh fruits and vegetables.

Cleese puckered his lips, made kissing sounds, gnashed his teeth. "Oh you little sweetie," he said.

A black lemur female jumped up on his lap and grabbed a quick bite of sweet peas -- then tried to swipe the bowl from him.

"Are you getting anything, or do you want a different angle?" Cleese shouted to photographers.

Soon after, he was seen bearing a lemur carrying case into the new habitat area. "This is the first time he's ever been in here," he said, opening the lid to applause. Out stepped Robo, a black and white ruffed lemur -- larger than a skunk, smaller than a fat raccoon.

Robo explored the perimeter, scaled a tree, scent-marked a few places on the ground and drank from a stream near a waterfall.

The lemur forest will open with 20 animals, representing five lemur species:

black lemurs, black and white ruffed lemurs, red ruffed lemurs, ring-tailed lemurs and white-fronted lemurs. It will be the first time that the zoo has had all five species at one time, and all five mixed together.

"It's the largest habitat for lemurs in North America," said John Aikin, the zoo's curator for planning and design. "I call them teddy bears with tails. "

The lush acreage has mature eucalyptus and cypress trees, bamboo and other grasses.

A multitiered observation deck will enable visitors to see lemurs in a variety of activities. There are towers with heated platforms and lemur ropes and toys.

Adults and children will be able to help feed the lemurs with the aid of food dispensers -- one looks like a ceramic Mexican hat -- that can be hoisted by ropes.

The zookeepers are also testing out heat lamps. Lemurs like to recline on their backs, stretch their paws and sun themselves.

Lemurs are one of the world's most endangered primates. They exist in the wild only in Madagascar off the southeast coast of Africa.

Lemurs were out-maneuvered off the continent of Africa. "They have the most gentle form of warfare," Cleese said. "They throw disgusting smells in the air,

and waft them with their tails."

They are forest-dwelling animals, but Madagascar has lost about 90 percent of its forests.

The San Francisco Zoo is headquarters for the Madagascar Fauna Group, a consortium of 40 zoos around the world. Eva Sargent, the zoo's director of conservation and science, leads efforts to pool the group's resources to save the island's wildlife.