Stanford students ease life in the zoo

A dozen Stanford sophomores have designed ways to enrich the lives of the giraffe, lions and kinkajou at the San Francisco Zoo.

- By Ruthann Richter

Lions at the San Francisco Zoo are among the beneficiaries of "enrichments" designed by Stanford undergraduates to engage the animals' interest.
Norbert von der Groeben

Most days, Floyd the giraffe can be found lingering by the rocks near the female enclosure in a remote corner of his paddock at the San Francisco Zoo.

But a group of Stanford University students is shaking up Floyd’s routine.

As part of Sophomore College — a two-week immersive learning experience — the students designed and built two giant, urine-soaked scratchers for Floyd, who has responded by spending a lot more time moving around his big pad, exploring his environment and making himself visible to zoo-goers. “You would think that making something like that would not be complicated,” said Jason Watters, PhD, vice president of wellness and animal behavior at the zoo. “But try making it for an animal that is 1¼ tons and very strong. You have to make it so it doesn’t break and so he can’t take it apart and hurt himself. There is a huge challenge there.”

A dozen intrepid, soon-to-be sophomores tackled this and other challenges as part of the class, designed to teach them about animal behavior, welfare and conservation, as well as the day-to-day workings and the mission of zoos. Zoo officials celebrated the students for their contributions at a ceremony Sept. 12.

The class was conceived by Joseph Garner, PhD, associate professor of comparative medicine at the School of Medicine, who said he had dreamed for the last 10 years of developing an educational experience of this kind.

With Stanford’s support, he joined forces with Watters, a friend and colleague from his postdoctoral days, to develop the program, which was offered alongside Sophomore College classes such as “Resistance Writing in Germany” and “Energy in the West.”

Three tough animals

For the students, it proved to be an intense experience that began with selecting three zoo animals for which they would develop an “enrichment” — something to improve the animals’ lives, ease the job of zookeepers and engage the public.

Though the students “absolutely picked the three hardest animals” for their projects — a giraffe, lions and a kinkajou — their solutions proved ingenious, Garner said.

“They all came up with phenomenal ideas — enrichments that work and that Jason and I hadn’t thought of,” he said.

For the lions, the students were inspired by a tidbit they learned from one of the caretakers: The big cats liked to roll in rhino dung, but were quickly bored by the experience.

“That was a little goofy for us, so we decided to play around with that idea,” said student Jennifer Ren. She and three fellow students worked through a weekend in the School of Engineering’s Product Realization Lab to build a contraption they dubbed the Poop Shooter. It’s based on a modified fish-feeder, a slow conveyor belt, which Watters had employed for dispensing food at various intervals to the anteaters.

Lured by a student-designed scratching post that carries the scent of urine from female giraffes, Floyd is now spending more time exploring his enclosure.
Norbert von der Groeben

Pellet dispenser

But instead of food, this device dispenses animal poop, which is in ready supply at the zoo. At random times throughout the day, it shoots giraffe and oryx pellets into the lions’ den, stirring the interest of the normally lethargic cats.

“It was amazing,” Garner said. “Lions lie around all day watching and waiting. But when the zoo put the enrichment in, it was like somebody just flipped a switch. The male lion was up and about and smelling and searching for the giraffe droppings, and performing all of this wonderful lion behavior.”

Student Marina Dimitrov noted that this form of enrichment is “100 percent sustainable and free,” and that using giraffe pellets, as opposed to the messier rhino poop, could be relatively easy for the keepers to manage.

For Floyd the giraffe, the students had to go through several iterations on the scratcher, built with thick manila rope and two-by-fours purchased at Home Depot.

Initially, “we thought it was great. We thought it was done,” said student designer Daisy McKim. “The curator loved the design but wanted it to succeed.” The students realized they had to reinforce the scratcher so Floyd couldn’t break it or chew through the rope.

“We wanted to make sure Floyd couldn’t rip it apart in 3 ½ seconds,” said student Tom Blackwood. “It’s now lasted for three days, so that’s good.”

Enticing a giraffe

The device really got Floyd’s attention when the team decided to soak it in female giraffe urine and then lay a trail of female feces leading up to it.

“That’s what made it work,” Garner said. The students tracked Floyd’s 24-hour movements through video cameras and found him ranging much farther than in the past.

“He’s really exploring more of his environment, which is what we wanted to see,” McKim said. By giving Floyd a chance to check out female urine, which contains important reproductive cues, it might have helped satisfy some of his curiosity about the females that he was straining to see, Garner said.

Stanford students Julia Olsen, Eliza Klyce and Jennifer Ren talk about the pellet dispenser they invented for the lion enclosure at the San Francisco Zoo.
Norbert von der Groeben

“At the enclosure for Harley the kinkajou, a doe-eyed, prehensile-tailed rainforest mammal related to the raccoon, the students came up with two devices to keep this social animal even more engaged. One they dubbed the “Tree of Ever-Changing Wonders,” a climbing structure made of PVC pipe that can be adapted for a variety of uses, such as hanging toys, and is especially appealing to a creature that spends its life about 80 feet up in the trees.

Smoothies for the kinkajou

The other invention was the “Robo-Flower,” in which Harley can use his prehensile tongue to savor smoothies (made from his normal fruit diet) from two electronically controlled dispensers in his enclosure. Both will be welcome additions to Harley’s environment, said Kate Sulzner, a veterinarian at the zoo’s wellness center.

“Having this permanent structure that is treelike and is easy to clean is awesome,” she said. “Having the students come here helps us think out of the box. We had never thought of smoothies before. It helps to have a fresh perspective.”

For the students, the experience offered a unique window into the animal world while giving them hands-on experience in creating something of social value.

“I love that it’s something practical that can be accomplished in two weeks,” said Blackwood, an engineering major.

And as Eliza Klyce, a computer science major, said, “It’s nice to do a design-oriented thing that isn’t software.”

About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit

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