Polar Bears as Patients: Caring for Animals at Henry Vilas Zoo

The Henry Vilas Zoo’s two polar bears, Bo and Berit, together in their Arctic Passage exhibit
The Henry Vilas Zoo’s two polar bears, Bo and Berit, together in their Arctic Passage exhibit
The Henry Vilas Zoo’s two polar bears, Berit and Bo, together in the Arctic Passage exhibit. KRISTIN MYERS/HENRY VILAS ZOO

Berit is relaxed and enjoys snacking on romaine lettuce. Bo is rambunctious and would rather eat lard.

The pair of polar bears, age 22 and 2, respectively, reside at Dane County’s Henry Vilas Zoo in the award-winning Arctic Passage exhibit. The two love snuggling and tally a combined weight of nearly 1,400 pounds. They’ve been together since January after Bo, short for Borealis, arrived from the Toledo Zoo.

Mary Thurber

“I am so lucky to get to work with such wonderful polar bears,” says Mary Thurber DVM’14, the primary veterinarian at Henry Vilas Zoo. Thurber is a clinical instructor of zoological medicine at the UW School of Veterinary Medicine and a board-certified diplomate of the American College of Zoological Medicine.

Since spring 2019, the SVM and its teaching hospital, UW Veterinary Care, have served as Henry Vilas Zoo’s contracted veterinary service. Thurber and other UW Veterinary Care Zoological Medicine clinicians and trainees visit the zoo three days each week, in addition to providing on-call coverage. They work collaboratively with two veterinary technicians at the zoo, animal keepers and zoo management to provide the highest possible level of animal care.

A variety of UW Veterinary Care specialty services, from Dentistry and Oral Surgery to Diagnostic Imaging to Ophthalmology, also lend their expertise as needed. And for the first time, this spring the school began offering a zoological medicine clinical rotation for fourth-year doctor of veterinary medicine students that includes visits to the zoo.

International Polar Bear Day

Feb. 27 marks International Polar Bear Day, meant to build awareness for the conservation of polar bears. Polar bear populations in the wild are declining as arctic ice shelves shrink and the animals have fewer places to hunt.

The Henry Vilas Zoo partners with the nonprofit organization Polar Bears International to help save wild polar bears and the sea ice they depend on. The zoo will host an International Polar Bear Day virtual celebration Feb. 27, with details to be posted to the zoo’s Facebook page.

“Our polar bears are great ambassadors for their wild counterparts,” says Henry Vilas Zoo polar bear keeper Kristin Myers. “We work closely with Polar Bears International to help teach people about polar bears, climate change and how they can help wild bears.”

“It’s a huge team effort,” says Thurber.

Day to day, the team’s work ranges from examining animals to giving vaccinations or testing for internal parasites to conducting surgery. Dedicated training from zookeepers aids these procedures.

For staff safety, many of the zoo animals must be sedated or anesthetized for hands-on medical procedures, for example, when conducting X-rays or an ultrasound, or sometimes when giving injections or drawing blood. But the zoo’s polar bears and many other animals are trained through positive reinforcement in several behaviors that help with medical care. This includes standing up, laying down, sitting, presenting a hip or shoulder, and more.

“When veterinary staff needs to look at certain parts of the bear, we will ask them to position themselves in a way that allows this to happen,” says Kristin Myers, one of the Henry Vilas Zoo’s polar bear keepers. (Staff always work with the bears through protected contact, meaning there is a barrier between them and the bears.)

“Our polar bears are very cooperative for injections, so they’ll voluntarily come over for a vaccine injection,” adds Thurber. “They’ll open their mouth to show us their teeth, and they’re trained to show us different parts of their body so we can do a lot of our veterinary assessment awake.”

Henry Vilas Zoo staff work on a blood draw behavior with Berit while she receives a continuous treat of honey water
Henry Vilas Zoo staff work on a blood draw behavior with Berit, where she places her paw in a specially designed chute in the enclosure while receiving a continuous treat of honey water. KRISTIN MYERS/HENRY VILAS ZOO

Berit has also been trained to place her paw in a specially designed chute in the polar bear enclosure, allowing staff to draw blood from the top of her foot while she receives a treat. (Occasional blood draws provide a useful tool for measuring organ function and other key health parameters.) Bo is now also being trained in this behavior.

“Bo trains mostly for his lard, and Berit likes to train for honey water and romaine lettuce, but both will do well-established behaviors for any treat,” notes Myers. The bears also enjoy enrichment multiple times a day. This can include extra training sessions, toys, and exploring new items such as novel food, smells or bedding.

For Thurber, it’s an honor to help care for such an iconic species, whose conservation status is listed as vulnerable due to decreasing habitat and populations in the wild.

“Polar bears are one of those species that you can’t help but love. With climate change, it’s easy to envision melting ice and losing polar bears, which would be so devastating,” she says. “Having the ability to care for the species under managed care is such a gift. They’re a great ambassador for the general public and to help inspire the next generation.”

Thurber notes the role of zoos in contributing to the conservation of polar bears and other species. For example, studies of the diet, metabolism and other characteristics of animals in captivity help provide a better understanding of animals’ needs in their wild habitats. And Association of Zoos and Aquariums (AZA) Species Survival Plans, overseeing the population management of many endangered species within AZA institutions, enhance species’ conservation in the wild.

“Truly every day, we are working to commit and contribute to conservation,” Thurber says.

Henry Vilas Zoo polar bears Bo and Berit nap together
Berit and Bo enjoy a nap. HENRY VILAS ZOO

Bo’s arrival to Henry Vilas Zoo this past fall, and the simultaneous transfer of the zoo’s previous male, Nuniq, to the Kansas City Zoo, were recommended by the AZA Polar Bear Species Survival Plan.

“These plans are an important tool in zoo management, helping to make sure we have healthy gene pools in captivity,” Thurber explains. “They’re looking to see which animals have been well represented genetically and using that information to make recommendations for which animals should go to which zoos for breeding.”

Having grown up in Madison, visited Henry Vilas Zoo as a child and attended the UW School of Veterinary Medicine, Thurber says, “it’s really wonderful to be home.”

“Having the opportunity to come back and provide veterinary care for the zoo was such an incredible opportunity and I’m so grateful for it,” she says. “I have loved having all of the different specialists at the vet school to collaborate with and it’s wonderful being able to provide gold-standard levels of veterinary care for our zoo animals.”

Meghan Lepisto

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