How San Francisco parks feed the koalas at the SF Zoo

How San Francisco parks feed the koalas at the SF Zoo

Jorge Trujillo was hanging precariously off the high branches of a tree near Lake Merced when he was scouted.

A former San Francisco Zoo keeper spotted Trujillo landscaping and stopped to tell him how impressed he was with his work. The zookeeper needed someone just like Trujillo and convinced him to leave his job. Twenty-four years later, Trujillo still works for the zoo in a role he could have never imagined even existed.

Trujillo is part of one of the zoo’s horticulture teams, which spends their days searching for eucalyptus in San Francisco parks that looks tasty enough for a koala. It’s part of the “browse” program — a zoology term for animals eating off the leaves of foliage — which supplies more than 60 tons of plant life per year for the zoo’s animals to enjoy. The group of six employees has more than 100 years of collective experience in the field, estimates horticulture manager Greg McCoy. They spend two to three hours each weekday cutting back shrubs and trees, using extensive knowledge to select the diverse vegetation that animals at the zoo will either eat or use as scent enrichment. 

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park on Sept. 6 to feed to the zoo's koalas.

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park on Sept. 6 to feed to the zoo’s koalas.

Charles Russo/SFGATE

Koalas are the only species that can consume eucalyptus since it’s toxic to most mammals. The animals have a unique stomach that can break down the toxicity as they digest it, and 1 to 2.5 pounds of leaves a day are required to keep them at their normal weight. Eucalyptus, for regions where it doesn’t grow well, is prohibitively expensive to ship in, and even if a zoo could afford it, it only lasts for a day or two once it’s unfrozen. For this reason, only 11 zoos in the country have koalas because they have to be able to support this type of feeding. 

The SF Zoo currently has two koalas, a 5-year-old male named Cobar Wollemi and a 2-year-old female named Stacey, and they wouldn’t have enough to eat without SF’s many parks. Trujillo has learned over the years that koalas are very picky eaters — they’ll only eat new growth eucalyptus, selecting just the tips of the branches cut for them. They get all their water intake from the plant and prefer a few different species of eucalyptus each day (even their keepers find their tastes unpredictable). The zoo’s current duo enjoy the more fragrant species of eucalyptus (there are about 15 species of eucalyptus in SF and about 50 in California), though sometimes they’ll even eschew branches they’ve previously enjoyed. “If it’s droopy, they won’t touch it,” Trujillo said. “They only want quality, they don’t want quantity.”

Stacey, a 2-year-old female koala at the San Francisco Zoo, is seen inside her habitat on Sept. 6.

Stacey, a 2-year-old female koala at the San Francisco Zoo, is seen inside her habitat on Sept. 6.

Charles Russo/SFGATE

Luckily, the invasive species grows wildly in San Francisco from when it was brought to the city in the 1850s by migrating Australians. The city needed quick-growing wood to supply the booming area, using it for everything from woodworking to firewood to providing windbreaks. 

Today, the browse team cuts about 5% of the plants it needs from Golden Gate Park and gets the rest from spots like McLaren Park, Stern Grove and even smaller parks like Golden Gate Heights. McCoy said he and his team know the city’s greenery better than anyone, and they’re always scouting for new places to cut. They may even stop when they spot a good-looking tree on the street or inquire at a construction site to save some soon-to-be cleared trees.

McCoy said the greenery is so plentiful in the city that they rarely have to check in with park managers to update them on where they’ll be cutting. At private sites, people often seem skeptical about requests to trim, McCoy said, until they explain they’re from the zoo and the cuttings will go to feeding a koala. Once he mentions that, they usually let him right in.

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park to feed to the zoo's koalas, on Tuesday, Sept. 6, 2022.

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park to feed to the zoo’s koalas, on Tuesday, Sept. 6, 2022.


Charles Russo/SFGATE

SF Zoo staff horticulturist Jorge Trujillo holds a large "bouquet" of eucalyptus harvested from trees in Golden Gate Park, on Tuesday, Sept. 6, 2022.

SF Zoo staff horticulturist Jorge Trujillo holds a large “bouquet” of eucalyptus harvested from trees in Golden Gate Park, on Tuesday, Sept. 6, 2022.


Charles Russo/SFGATE

Three different varieties of locally-harvested eucalyptus are stories in a loading area of the koala habitat, at the San Francisco Zoo, on Tuesday, Sept. 6, 2022.

Three different varieties of locally-harvested eucalyptus are stories in a loading area of the koala habitat, at the San Francisco Zoo, on Tuesday, Sept. 6, 2022.


Charles Russo/SFGATE

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park to feed to the zoo's koalas, on Tuesday, Sept. 6, 2022.

SF Zoo staff horticulturist Jorge Trujillo harvests eucalyptus branches in Golden Gate Park to feed to the zoo’s koalas, on Tuesday, Sept. 6, 2022.


Charles Russo/SFGATE


(Charles Russo/SFGATE)

But it’s not just cutting down branches. Each and every trimming needs extensive documentation, noting the species of the plant and the exact location of the cut. This way, the animal keepers can learn from each batch, weighing how much the koalas ate every day from the cuttings. McCoy said, for example, one time they cut from beside a freeway ramp and the koalas didn’t like that much, so they don’t return to that area.

The department often receives calls from people who know about the program and have trees they’re planning to cut down. Often, the leaf gatherers will hop in their trucks and head straight to the site.

While the browse team is crucial for the zoo’s koalas, it also provides for more than 100 other animals, including giraffes, rhinos, gorillas, lemurs and red pandas. Even if the animals don’t eat the plants, the foliage can be played with or used for scent exploration. Acacia longifolia, another plant native to Australia, makes up a large portion of the team’s other cuttings, adding up to about 30 tons per year. Sometimes, the zookeepers may even request the team to search out certain species that specific animals might enjoy. 

Animal care specialist Ross Anthold carries Cobar, one of the zoo's two koalas, at the San Francisco Zoo on Sept. 6.

Animal care specialist Ross Anthold carries Cobar, one of the zoo’s two koalas, at the San Francisco Zoo on Sept. 6.

Charles Russo/SFGATE

Not every zoo has a browse program, as it needs the climate to support it. “We probably rate in the top 10 in the country [for our browse program] because we have almost 10 months of growing,” McCoy said.

Back near the intersection of 38th Avenue and Lincoln Way, Trujillo crushes eucalyptus leaves between his fingers to bring out the oils and emphasize how different one species might smell from another. He then points to the different colors and textures of certain leaves, showcasing the delicate stems the koalas favor. The zookeeper that scouted him and later trained him retired years ago, and now Trujillo trains all new browse employees. “It’s amazing how time flies,” he said. “Twenty-four years later, I’m still here.”

Horticulturist Jorge Trujillo, who has worked at the San Francisco Zoo for 24 years, is pictured in Golden Gate Park on Sept. 6.

Horticulturist Jorge Trujillo, who has worked at the San Francisco Zoo for 24 years, is pictured in Golden Gate Park on Sept. 6.

Charles Russo/SFGATE