March 2, 2024

According to a notable new study comparing the open air life of grizzly bears to ours, grizzly bears navigate landscapes much like most people, preferring flat roads over slopes and lush speeds over sprinting.

The research, which included captive and wild bears, a customized treadmill, apple slices, and GPS trackers, expands our understanding of how the natural drive to conserve energy determines the behavior of animals – and our own – and ramifications for that Life and health can have and weight control. The results also explain why bears and humans cross paths so often in the vast wilderness, and give us useful information for planning natural spaces and for the safety of all.

Over the past few years, biologists and other scientists have become increasingly interested in the way we and other creatures move through our environment, and while some preliminary answers emerge about why we choose to move and transit, the results are not generally particularly satisfactory.

Research suggests that humans as a species tend to be physically lazy, with a predetermined tendency to avoid activity. For example, in an insightful 2018 neurological study, brain scans showed that volunteers were much more interested in pictures of people in chairs and hammocks than people in motion.

This seemingly innate predilection for sedentary lifestyle made sense to us long ago, when hunting and gathering required great effort and copious amounts of calories and resting under a tree didn’t. Being inactive is more of a problem these days as there is food everywhere.

However, it is not clear to what extent we share this propensity for tranquility with other species, or whether these preferences affect the way humans and animals travel the world.

So this is where grizzlies come in, especially those who live in Washington State University’s Bear Center, America’s premier center for grizzly conservation and research. University biologists affiliated with the center study how animals live, feed and interact with people.

For the new study, recently published in the Journal of Experimental Biology, they decided to analyze exactly how much energy grizzly bears use when moving in different ways, and how these and other comparable numbers affect behavior in real life could, not only from bears, but also from bears from us and other animals.

First, they built a solid structure around a treadmill that was originally made for horses. With some modifications, it could tip up or down as much as 20 percent while supporting the size and weight of a grizzly bear. At the front of the structure, the researchers added a feeder with a built-in rubber glove.

Next, the nine brown bears, including men and women – most of them downtown residents by birth and with names like John, Peeka, and Frank – were taught to get on the treadmill and move forward while quietly making sausages and apples accepted as a reward.

“Grizzlies are very fond of eating,” said Anthony Carnahan, a doctoral student at Washington State University who led the new study.

By measuring the changes in the composition of the air within the structure, the researchers were able to record the energy consumption of each bear at different speeds as it walked uphill and downhill. (The bears never ran on the treadmills for safety reasons.) Using this data, the researchers found that the bears’ most efficient physiological rhythm (the one that needs the least oxygen) is about 4.1 kilometers per hour.

Finally, the researchers compiled the available information on the wild bears’ trajectories using GPS statistics from the brown bears from Yellowstone National Park, along with map data and comparable numbers from previous studies of humans and other animals roaming natural landscapes.

When comparing the data, the scientists found that wild brown bears, like us, were born to laze about. Researchers expected the wild bears to move at their most efficient pace whenever possible, Carnahan said, but in reality their average pace through Yellowstone was 2.25 kilometers per hour, a physiologically ineffective pace.

Also, they almost always took the least steep route to get anywhere, although it would take longer. “They went upright a lot,” said Carnahan.

Interestingly, these speeds and routes are similar to what humans use when choosing routes through the wilderness, the researchers found.

Taken together, the results suggest that the innate urge to avoid exertion plays a bigger role in the behavior and mobility of all creatures, large and small, than we can imagine.

However, the study doesn’t rule out that grizzly bears, like other bears, can move with sudden and amazing speed and ferocity if they choose to, Carnahan notes. “I saw a bear running through a mountain meadow in six or seven minutes than it took me all afternoon,” he says.

Nor do the results tell us that people are predestined to always walk slowly and stick to flat areas, only that it may take both mental and physical exertion and goal setting in order not to get into the Ease to fall routes.

Finally, the study reminds us that we share nature with large predators, which of course can choose the same paths as us. Useful information on brown bear safety on the territory can be found on the website of the Interinstitutional Brown Bear Committee.