"This is Otis, a 13-week-old male African lion. You sleep with stuffed animals; Otis here sleeps with stuffed people." Bobby Lewis, assistant manager of Vienna's Pet Farm Park, sits cross-legged in Otis' cage, cradling the cub's head in his lap. With closed eyes, Otis contentedly sucks Lewis' finger. Next to 30-pound Otis is a battered Raggedy Ann. "Otis bit off her foot," Lewis tells a group of four-h are sharp but he doesn't bite anyone hard." Otis is one of about 225 animals at the park, the majority of which can be petted. And some can even be ridden, like 300-pound, 95-year- old Homer and Jethro, Aldabra turtles. "Children under 60 pounds can ride them if they can get the turtles to move," Lewis says. Some animals, of course, can only be touched under supervision, lke seven-foot, 30- pound Zelda, a red-tailed boa constrictor. Lewis allows Zelda to wrap herself around his torso and invites the children to touch her so they can discover for themselves that she isn't wet and slimy. "She's really smooth. Can I have her?" one child asks after petting her. "You can get a baby at a pet store for $39.50," he tells her. Another child, reaching out to pet Zelda, wants to know if she'll bite. "She might if you upset her." "Could she kill you?" another youngster inquires. "If she got around my neck she could squeeze me to death. She kills her prey by constricting." The farm feeds her live rats. The group moves on to catch a glimpse of Fannie Mae, a white-handed gibbon, swinging from limb to limb on her moated island. She's afraid of water and is territorial so she remains on the island, says Lewis. "How do you feed her?" one worried girl asks. "I slip a board with food on it to her," Lewis says. "Let's see if I can get her to speak to us." He hoots at Fammie Mae who soon returns a siren-like hoot. "She's saying, 'Stay off my island.' She's warning us." No one dares approach her through the three-foot deep water of the moat. Nearby, in the barn, counselors are rescuing a six-year-old boy who's run out of food and been cornered by three hungry goats. Lewis hands a wafer cone filled with either alfa-corn (compressed hay) or crimped (cracked) corn to each child, instructing them to pour the feed into their hands and hold them open while feeding the animals; otherwise most of the animals will eat the whole cone. A dainty girl in a sundress and sandals feeds the goats: "They feel soft. It's scary at first. It seems as if they'll bite your hand off. Then it tickles." She laughs. Soon only the cone remains. "Can I eat the cone?" She gazes at it longingly. A counselor directs her to feed it to a flightless emu, or to a donkey, llama, horse, pig or sheep. Among the creatures in the barn, only the sow and her piglets and the Patagonian cavvies, the world's largest rodent, don't eat cones. "You don't want to feed the zebra because she may eat your hand. She takes big bites," Lewis warns everyone. After the barn visit, the group climbs aboard a wagon for a good old-fashioned hay ride. Lewis, piloting the tractor that's pulling the wagon, drives into the 60-acre field that is home to the wild animals and stops to pick up a three-pound ostrich egg laid that morning. He hands it with care to a counselor, explaining that, if it's fertile, it will be hatched in the farm's incubator. Lewis pulls up to a male buffalo weighing 2,000 pounds, his head alone weighing 300. "This buffalo is not smart," Lewis says with conviction. "His brain is the size of a tennis ball. All he does is eat, sleep, roll and far too soon for the fascinated children. UP CLOSE AND ANIMAL

PET FARM PARK -- 1228 Hunter Mill Road, Vienna. Open 10 to 5 daily. Admission: $3 adults, $2.50 children; group rates: $2 per person for a group of 10 or more (with every 10 children, one adult admitted free); senior citizens and handicapped, $2 per person. Season passes: $12 per person, $40 per family. For group tours (10 or more) call 759-3637 a week in advance. Families visiting on their own can learn about the animals from plaques attached to cages and fences. Pony rides are also available: 50 cents for 150 yards; children's weight can't exceed 70 pounds. Hay wagon rides free on weekends, 50 cents on weekdays, six- person minimum. PETTING ZOOS

Here are five more petting zoos within weekend range of D.C.

NOAH'S ARK -- Cabin John Regional Park, Tuckerman Lane and West Lake Drive, North Bethesda. Open 10 to sunset daily. Free. Children can pet mules, sheep, goats and other small animals in the wooden ark.

BALTIMORE ZOO -- Druid Hill Park, Baltimore. Open Monday to Saturday 10 to 4:20, Sunday 11 to 5:20. Adults $1.50; children two to 11, 50 cents; senior citizens $1. The zoo's children's section is one big petting area, with goats, sheep, ponies, fowl, donkeys, etc. But the zoo has a strict no-feeding policy. 301/396-7102.

CATOCTIN ZOO -- About 12 miles north of Frederick on U.S. 15. Open 9 to 5 daily. Adults $3.95, children $2.95, under two free. The zoo has a two-acre petting section where children can pet llamas, donkeys, sheep, goats, etc., and buy food, 25 cents a packet, to feed them. The zoo also has wild animals in cages. 301/271-7488.

WILSON'S PETTING ZOO -- Frederick County Route 644, about four miles southeast of Winchester. Open weekdays 11 to 5 till September 16, weekends 11 to 7. Through October, weather permitting open 11 to sundown on weekends only. Adults $2.50, children 11 and nder $1.50, under one free. The pet farm is a 15- acre fenced-in area, with pygmy goats, deer, rams, turkeys, guinea pigs. Children can buy animal feed at 50 cents a bag. The zoo also has exotic animals in cages, including bears, lions and lots of monkeys. 703/662-5715.

NATURAL BRIDGE ZOO -- one mile north of Natural Bridge, Virginia, on Route 11 near Glasgow. Open 10 to 5 daily, till November. You can buy feed for 25 cents from a vending machine and offer it to deer, elk, goats, etc. in a five-acre fenced area. The zoo also has zebras, ostriches, leopards, bears, camels, etc. 703/291-2420. LOOK, DON'T TOUCH

For jittery little ones (and their parents) who'd rather get a close look without actually touching or joining the animals in their pens, here are some local places where you can watch animals up close.

OXON HILL FARM -- Oxon Hill Road (Exit 3A off the Beltway). Open 8:30 to 5 daily. Horses, cows, rabbits, fowl and pigs. Call ahead to find out if there's a special demonstration, such as cow-milking, scheduled. Free. 839-1177.

OLD MACDONALD'S FARM -- Wheaton Regional Park, off Georgia Avenue on Shorefield Road, three miles north of the beltway. Open 10 a.m. to one hour before sunset. A miniature barnyard with little red barn and pens holding goats, chickens, sheep, ducks, ponies and burros. Free. 622-0056.

CLAUDE MOORE COLONIAL FARM -- 6310 Old Georgetown Pike, McLean. Open April to December, 10 to 4:30 Wednesday through Sunday. Adults $1, children 50 cents. Cows, calves, pigs, chickens, one horse and an ox. Call ahead for information on special weekend events. 442-7557.

FRYING PAN FARM -- 2709 West Ox Road, Herndon. Open daily 10 to 6. A model working farm circa 1920. Animals include horses, sheep, pigs, goats, turkeys, geese, chickens, etc. Free. 437-9102.