Jorge Trujillo spends days gathering silvery-green leaves. He’s not a botanist or arborist. The San Francisco Zoo employee collects eucalyptus for hungry koalas. His zoo is among those that forage to feed their animals.
Migrating Australians brought eucalyptus seeds to California in the 1800s. The plant spread nearly out of control.
“As soon as it starts outcompeting native species or fundamentally changing the environment so that native species can’t grow there,” says botanist Jenn Yost, “we would consider that an invasive species.” Today, eucalyptus flourishes in several San Francisco city parks.
Eucalyptus leaves are toxic to most mammals. But God created koalas to relish what other animals reject.
For koalas, eucalyptus is more than food. Ross Anthold, the zoo’s animal care specialist, says, “[The leaves are] also where they get their water.” Koalas can consume more than two pounds of leaves per day.
To help feed the zoo’s two koalas, workers gather about 60 tons of plant life from city parks each year. They forage locally because eucalyptus is expensive to ship and lasts only a day or two unfrozen.
Plus, Anthold says koalas are picky, preferring the young, new plant growth. That’s the part with the most nutrients.
Despite eucalyptus’ prevalence in San Francisco, Trujillo says the plant is not always easy to find: “Sometimes we struggle very much, especially in the winter,” he notes. “In the summer, it’s a little easier.”
The effort and expense of obtaining eucalyptus means only a few zoos around the world—in places where eucalyptus grows—keep koalas.
Other zoos also scavenge vegetation to feed their animals. Oakland (California) Zoo’s Senior Keeper Leslie Rao says harvesting locally became vital during the pandemic—when zoos needed to feed animals without income from visitors.
Rao says workers can’t grow enough food for the zoo’s big eaters, so the zoo asks for help from the community. Zookeepers solicit branch donations from oak, poplar, sumac, and many fruit trees for use in the zoo.
Some landscapers donate the branches of another invasive species, the African acacia tree, to the Oakland Zoo. That tree’s leaves are a favorite of the zoo’s five giraffes, which can eat about 75 pounds of food per day . . . each.
The Cleveland (Ohio) Metroparks Zoo grows plants on zoo grounds for its largest creatures but also supplements from area parks.
“Park managers will contact us when they think they have something we can use,” says Leigh Anne Lomax, the zoo’s horticulture manager. “Some are nice enough to let us harvest responsibly in select areas.”
Why? God created each animal with unique needs and preferences. Paying attention to those needs with creativity and effort shows good stewardship and honors the Creator.