During a particularly brutal Chicago winter in 2014, photographer Sheng Wen Lo remembers reading that it was too cold for polar bears housed in the city’s Lincoln Park Zoo to go outside. It sounded like the lead-up to a bad joke, but it was true. Captive polar bears aren’t as tough as wild ones. Their skin is thinner and they can’t withstand extreme cold.

The news was particularly striking to Lo. For three years, he has been photographing captive polar bears in 25 zoos and other enclosures in Europe and China. The series, called White Bear, exposes the welfare of animals within artificial habitats by observing their behavior.

It’s tempting to look at Lo’s images as a pointed argument against keeping polar bears in zoos. And in many ways, polar bears are unique: They’re charismatic zoo animals well-known to tourists, they represent a unique and remote ecosystem, and they are highly sensitive to environmental change. Yet Lo intends the series—and the bears—to provoke larger questions about which animals are suited for captivity, and which might not be.

Lo approaches animal captivity the same way he approaches computer science, in which he has a master’s degree. Before even taking the first picture, Lo consulted a veterinarian about how to read the actions of polar bears (i.e. is pacing always a sign of distress?) Then, while developing the series, he invited zoology experts to view the work and advise on whether the images were in line with zoological understanding about how behavior explains the welfare of captive animals.

View Images Wildlands Zoo, Netherlands. 2016 Photograph by Sheng-Wen Lo

But the Taiwanese photographer says that the images began, and remain, a personal exploration of the relationship between human beings and animals and their respective places in the world. “I like to understand how I am related to animals,” says Lo. “I’m surrounded [by animals] in the environment...I see animals. I consume animals. I drink milk. Animals are linked to me, and I feel there are a lot of hidden stories behind animals that are not made explicit.”

Reading short stories like Franz Kafka’s “A Report to an Academy” kindled the creative and scientific parts of Lo’s mind and set in motion his initial questions about the convoluted links between humans, animals, and captivity. Kafka’s story, told from the perspective of a trapped ape who teaches himself to be human in order to escape, explores themes of captivity—both animal and human—as well as the relationship between identity, performance, and assimilation. The poetic story made Lo wonder if he could explore the same complex questions through photographs.

An afternoon at New York’s Bronx Zoo in 2011 helped Lo decide which animals to observe. In the polar bear enclosure, his eye was drawn to the white paint designed to look like snow. Some of the paint had flaked off, revealing the concrete underneath. Lo wondered if the paint made any difference at all to bears that have never seen a real iceberg or real snow. Was it for the bears, or for the audience?

Lo wasn’t alone asking questions at the Bronx Zoo that day. The audience beside him questioned out loud whether the polar bear, named Tundra, belonged there. The artificial habitat seemed to contrast so dramatically to traditional environments of polar bears, in the Arctic, that the strange-looking environment had the curious effect of making the bears look sad.

Lo knew he didn't want to make another series of sad-looking zoo animals. He sought to reveal the animals as the complex beings they are. He is not interested in showing them as simply vulnerable or as victims, unrepresentative snapshots that can be used to advocate against their captivity.

View Images Aquazoo, Netherlands. 2016 Photograph by Sheng-Wen Lo

View Images Polar Ocean World, China. 2015 Photograph by Sheng-Wen Lo

With this motivation, Lo began photographing the bears in 2014. He spent a month at zoos in Europe, and then another month at zoos in China. He limits himself to two days per location and spends the opening hours of the zoo planted in front of the polar bear display. The process, he acknowledges, is intense. He says he only eats bread and apples while shooting—the same diet as the bears, but in his case, to reduce overhead costs.

Lo has observed funny and bizarre things while photographing the bears. On one hot day in Beijing he watched a young girl scream, “The bears are afraid of the heat!” in response to a sign explaining why the bears are biologically well-suited for cold weather. In China’s Xi'an Qujian Polar Ocean Park, the bears are placed within a structure designed to imitate the Loess Plateau, a semi-arid environment filled with powdery soil that is highly susceptible to erosion. “It puzzles me to this day,” says Lo. In Wuhan Haichang Polar Ocean World, the polar bears on display turned out not to be actual polar bears, but a mixed breed from a brown bear and a white bear.

On occasion, the sublime also gives way to the surreal. After spending 10 to 20 days straight peering into one zoo enclosure after another—often dark, cramped places—Lo found that captivity, even if voluntary, can bring on anxiety and other psychological effects. “If there are two or three days that I’m not in a zoo, I feel very strange.”