Amazon is one of the most widely used websites in the world. Thanks to their #StartWithASmile program, customers can now elect to donate 0.5% of their purchase to the charity of their choice at! For more information about how you can help the Phoenix Zoo, please see our AmazonSmile page or consider a purchase from our Amazon Wish List. Read below to see how longtime Zoo employee, Hilda Tresz, starts with a smile every day.

A Reason to Smile: Hilda’s Story

Hilda Tresz starts with a smile every day, and for good reason. After all, she has (literally) saved the lives of thousands of animals during her lifetime, and her passion for animal welfare, enrichment and global conservation knows no bounds.

Tresz was born and raised in Budapest, Hungary during a time when most people believed only men could work with large animals and a woman’s responsibility was at home caring for children.

Hilda, however, did not share this belief (and rightfully so).

Tresz began her work as a zookeeper in the Budapest Zoo after graduating high school. At just 18-years old, she was a small mammal keeper whose main responsibility involved hand-rearing the infant animals. After a few years, she and her husband, Zoltan, immigrated together to the United States in 1989.

That’s when her life’s mission shifted.

Tresz was hired at the Primate Foundation of Arizona and had the privilege to work with 85 chimpanzees during her tenure. Working with so many individuals was an unforgettable experience leaving an indelible impression on her. In fact, that’s when she became an unwavering advocate for the species.

In 2002, Tresz became the Behavioral Management Coordinator for the Phoenix Zoo. She worked with a variety of species, but primates remained her focus at all times. By overseeing the Zoo’s comprehensive behavioral management programs, she was fortunate enough to mentor staff, interns, and volunteers in regards to training animals, providing proper environmental enrichment, and conducting scientific research.

In 2007, ChimpanZoo Director, Virginia Landau, PhD, contacted Hilda regarding cooperative work on implementing similar enrichment concepts used at the Phoenix Zoo. Hilda then became a mentor and later the Volunteer Coordinator for the Jane Goodall Institute. Since then, she has held workshops, lectures, and has worked with zoos all over the world to enhance the psychological well-being of chimpanzees and other species.

“[Hilda is] … a mere goddess that works miracles,” Virginia Landau said. “Joking aside, I think [Hilda is] truly the goddess of chimpanzees. Needless to say, she is the “queen bee” of enrichment ideas as well as the author of a practical plan for enriching zoo animals.”

Tresz has nearly 30 years of experience with exotic species in zoo animal husbandry, enrichment and training. She holds triple-major degrees in biology, geography and education. Recently, Tresz was a recipient of the American Association of Zookeepers Lee Houts Environmental Excellence Award for her efforts.

Currently, Tresz is the Behavioral Enrichment and International Animal Welfare Coordinator at the Phoenix Zoo. Her responsibilities include developing and overseeing the Zoo’s Behavioral Enrichment Program. Behavioral enrichment enhances the lives of animals in a managed setting by providing them with mental and physical stimulation to increase natural and healthy behavior, such as puzzle feeders which encourage foraging or obstacles in habitats to maneuver around.

Additionally, Tresz serves as an ambassador of the Zoo consulting on animal welfare issues worldwide.

“Hilda has been known to me for several years,” Jane Goodall said. “The former director of our ChimpanZoo program, Virginia Landau, contacted me after reading an article in which Ms. Tresz was advocating enrichment activities for captive chimpanzees – ideas which she and I had been advocating for years. Dr. Landau told me, ‘I have found a jewel.’ Because of her skill, dedication and persistence, her diplomatic approach to sometimes complex situations, and because she truly cares, Ms. Tresz has been able to help many chimpanzees and zoos in many parts of the world.”

Now that’s a reason to smile.

Hilda’s Work: