Gus, the Philadelphia Zoo's resident male giraffe, knows when it's snack time.

The minute he spots zookeeper Wendy Lenhart, the gangly giant ambles toward a feeding area overlooking the spacious enclosure he calls home.

Like a kid licking a lollipop, Gus wraps his 18-inch tongue around an acacia tree branch and strips away its luscious leaves.

Soon, Gus is joined by Stella, his mate, and their offspring, 3-year-old Abigail.

Lenhart, 34, a 1997 Exeter High School graduate, is accepted without hesitation by the giraffes.

In the two years she's been their keeper, she has forged a relationship of trust and confidence that bridges the biological divide separating animals and humans.

In consultation with staff nutritionists and veterinarians, she oversees their feeding and health care. She also trains the giraffes to allow veterinarians to administer medical procedures.

"My job is to make sure they're comfortable," Lenhart said. "And to see that they get what they need."

Fantastic journey

Larry A. and Arlene K. Lenhart wanted their daughter to have a secure future, so they insisted she major in agricultural education at Penn State's main campus.

Truth be known, Lenhart's heart was in the outdoor aspect of her minor, wildlife and fishing science.

After student teaching at Twin Valley High School, she realized she was more interested in the subject matter than the teaching.

Ironically, she began her career in the education department of the Philadelphia Zoo in fall 2001. After going to Salt Lake City for an internship in aviculture, the raising and care of birds, and spending a short stint at the San Antonio Zoo, she returned to Philadelphia as a bird keeper in 2002.

For eight years, she would tend the zoo's macaws, Southern ground hornbill and a pair of storks named Will and Grace.

With Villanova University ornithologist Robert Curry, Lenhart did a field study of chickadees in Nolde Forest state park. Their research found that female chickadees in Nolde Forest preferred the song of Carolina males of the species when choosing a mate.

While birds remain an interest, Lenhart has tended the giraffes and the zoo's family of 10 kangaroos for the past 2½ years.

"Taking care of these fantastic animals," she said. "I feel like I'm making a difference."

Gentle giraffe

Just like people, Lenhart said, giraffes have personalities.

Stella, who's 12 years old and came to Philadelphia from the Cape May Zoo, is meticulous about clearing hay from her nostrils.

"She manages to get it out with her tongue," Lenhart said, "or sometimes she just sneezes on you."

Gus, who's six years younger than his mate, is sort of laid-back. He came to Philadelphia from the Caldwell Zoo in Tyler, Texas.

Abigail, or Abby, who was born in Philadelphia, likes to uproot grass growing along a moat that borders their habitat. She doesn't eat it, but tosses it about as if it were a toy.

There are nine species of giraffes, and Philadelphia's are reticulated. That means they have white netting over a brown coat.

"It's like you threw a white net over a brown giraffe," Lenhart explained.

While no two markings are the same, Abby's patterns are similar to her mother's. Gus' are lighter in color.

Giraffes have four stomachs and, like cows, have a ruminant digestive system.

They're main diet is alfalfa hay and a special grain mixture. They snack on acacia, apples and carrots.

Between them, the giraffes consume a 50-pound bail of hay daily. Gus gets eight pounds of grain, and the others get five pounds each.

Competition for food on the African plain, where giraffes originated, accounts for the disproportionate shape of their long necks. While other species evolved as grazers, giraffes are browsers, meaning they eat foliage instead of grass.

"The shape of their mouth, their high neck and long tongue enable them to reach the branches of the acacia trees on the African plain," Lenhart said.

Giraffes are in decline in the wild, she noted, but are not as endangered as rhinos.

Rescuing rhinos

Tony, the Philadelphia Zoo's resident rhino, is one of Lenhart's favorite animals.

Rhinos are an endangered species, mainly because of poaching. In some parts of the world, the rhino horn is considered an aphrodisiac.

"It's so ridiculous," she said. "Their horns are made of carotene, the same stuff that's in your fingernails."

As a board member of the American Association of Zoo Keepers, Lenhart is involved in efforts to save rhinos.

She coordinates Bowling for Rhino, a project of the association's Philadelphia chapter. Since the mid-1990s, it has raised $130,000 for association preserves in Kenya, Java and Sumatra.

On May 5, she helped coordinate Cinco de Rhino, a walk/run from the Elmwood Park Zoo in Norristown to the Philadelphia Zoo to raise money for rhino preservation.

Scores of supporters, wearing imitation rhino horns, paraded between the two zoos.

Berks connections

Lenhart still has connections to Berks County, and cherishes growing up in the Reading area.

Her father, a retired utility worker, still lives in Exeter. Her mother, who had been a teaching aide at Amity Primary Center, died in 2008. A brother, Michael A. Lenhart, lives in Hereford Township.

Her grandfather, the late Elmer Lenhart of Mount Penn, was a well-known Berks County well driller.

"I loved my grandfather," she said. "He was a real character."

Lenhart lives in Brewerytown, a section of Philadelphia, and walks to work.

"It's the job I always wanted," she said, "and hope to enjoy for a long time to come."