At Slottsskogen Children's Zoo in Gothenburg, eight Gotland Russ horses spend their days surrounded by the sounds of childhood—laughter, chatter, sticky fingers reaching to stroke their muzzles. A new study from the University of Gothenburg confirms what their caretakers have long suspected: these horses are entirely unbothered by the attention. What does stress them, however, is surprisingly specific—the rumble of an excavator next door was enough to spike their heart rates and send them bolting away.
For zoos committed to both animal welfare and species conservation, understanding how captive animals respond to human contact matters enormously. Visitors are essential to zoos' missions, but their presence comes with unknowns. Researchers led by Isidora Dundjerovic fitted heart rate monitors to the eight horses to move beyond behavioral observations and measure the animals' actual physiological response to their busy lives in the park. The findings, published in Zoo Biology, offer reassurance and nuance about what genuinely stresses these animals and what they can happily tolerate.
The baseline data was telling. When the horses rested, their hearts beat at an average of 42.5 beats per minute. During exercise—walking through the park for hours—that climbed to 85 beats per minute. Then came the real test: researchers measured their heart rates while children petted them as they ate hay near a playground. Their hearts settled at 51 beats per minute, barely elevated above resting. Dundjerovic noted that "although a great deal can be gleaned from the animals' behavior, there is still some uncertainty about how they feel in the company of humans." The heart rate data provided clarity they couldn't get from observation alone.
What emerged was a picture of animals surprisingly selective about what bothers them. During walks through the park, the horses encountered barking dogs on several occasions without any measurable spike in heart rate. Passing cars left them unmoved. But when an excavator fired up next to their paddock, their heart rates shot up significantly and they quickly retreated. The distinction matters: it's not human presence or activity per se that troubles these Gotland Russ horses, but particular types of noise and machinery.
This finding reflects a deeper truth about horses—that they have coexisted with human caretakers for thousands of years and have adapted to many aspects of our world. Dundjerovic emphasized this continuity: "Horses have coexisted with the people who care for them for thousands of years. We now know a little more about how they are affected by being in an environment with lots of people, which is important for ensuring their welfare."
The results have already sparked momentum at Slottsskogen. Linda Thelin, a zoologist at the animal park, called them "reassuring" and pointed to an encouraging pipeline of additional research, including a similar study on pony riding. "Animal welfare is extremely important, and we monitor the health and well-being of our animals in many different ways," Thelin said. The collaboration between the zoo and the university represents a model of science in service of care—rigorous measurement applied to ensure that the animals thriving in public spaces aren't hiding stress beneath the surface.