Imagine.

It's a lovely morning in the village, and you are a horrible goose. More specifically, you’re a  bar-headed goose, and you’re about to embark on a migration across the  entire Himalayan mountain range.

You’ll regularly soar at  altitudes over 7,000 meters, and by some accounts, even  above the peak of Mount Everest. To be able to pull this off, a human  would need to train for months to build up the lung capacity to handle  the thin oxygen levels at altitude and build their endurance to  keep going for long hours… to say nothing of sprouting some wings. But you, a bar-headed goose?

No extra training whatsoever. In general, it’s hard to catch animals exercising. You’re not going to find a  capybara pumping iron at the gym.

But animals do routinely pull off feats of incredible strength and endurance. And they don’t need to hit the  treadmill to stay in shape, as far as we can tell. So… do animals exercise?

And  if not, why don’t they need to? [♪INTRO] Let’s just clear out the boring answer first. Almost every animal is on the move for at least some part of its life cycle, and running is not an exclusively human feature. One entire special issue of a journal  looked at the concept of exercise in animals, but they used a very  broad definition of exercise — basically just any physical activity  that’s more intense than normal.

By this definition, many animals  exercise on a near-daily basis when they run away from predators or towards prey, or when they engage in physical  matches to win mates or territory. Other definitions of exercise  include more intentionality. One review article on animals’  physical activity cites the definition from the American College of Sports  Medicine, which requires exercise to include structured movement  intended to improve physical fitness.

By this definition, a lot of the scientific literature will say that  wild animals can’t exercise. We can’t assume that animals have intention to exercise beyond their instinct  to survive, and if they do, it’s under the influence of a meddling human. Like training your hamster  to run an obstacle course, or the Iditarod with those very good dogs pulling their human on a sled for over 1500 kilometers.

In order to explore the question  of whether wild animals exercise, it’s worth considering the  reasons humans exercise. We can’t know whether animals  have similar reasons, but we can compare the behaviors they  perform and the results they get. The first reason that people  might exercise is for fun.

Kicking around a soccer ball with  your buddies or taking a dance class can be a great hobby that involves  physical activity, and your primary motivation for joining community  soccer is probably not life or death. Animals also exhibit lots of play behavior, which is a surprisingly rich and  complicated field of behavioral science. I can’t ask my cat why she runs  around in circles backflipping off of her cat tower, but  he seems to have a reason.

Young animals play to develop  both physical and social skills, including hunting. And a  well-beloved study from 2014 put a hamster wheel out in nature  and found that thousands of curious critters came to  take the wheel for a spin. So while play is complicated  enough to get its own episode, we can tentatively say “physical  activity equals fun” in some cases.

Humans also exercise to look good. In the movie Crazy, Stupid,  Love, Ryan Gosling forces Steve Carrell to go to the gym  as part of his glow-up montage. And bodybuilders stack their muscles way beyond what is necessary for healthy physical function.

In the animal world, showing off through physical activity often comes in the  form of fighting for a mate. One of the more hardcore of these  rituals is kangaroo boxing matches. I don’t know when you last saw a male kangaroo, but they are JACKED.

Female  kangaroos definitely notice, and they might be swayed by the  visual appeal of a ripped suitor. Male kangaroos have been observed literally striking a pose to flex  their muscles for a female. But these huge muscles may be a  natural byproduct of hopping around with a massive body all day every  day and using their muscles to fight, rather than specifically  exercising to gain vanity muscles.

So I’m a little more hesitant  to call this one “exercise.” Other animals use methods of  attraction that are a bit more demure, like the majestic Birds of Paradise. While some birds compete with bright  colors and attractive feathers, the glorious Bird of Paradise uses that and more in its delightful mating dance. It could be argued that the  Bird of Paradise dance is indeed a form of exercise, as they  inherit the instinct of the dance steps through genetics, but they  also train to hone their craft.

While they pop out of the  egg knowing how to dance, the males spend months  rehearsing and training the steps with their buddies before performing for a female. Kind of like Ryan Gosling as  Ken in the 2023 Barbie movie, when he tries to out-dance the  other Kens for Barbie’s attention. Human workout aesthetics  aren’t limited to bulking up.

As anyone who spends enough  time on social media can attest, we humans may also motivate ourselves to exercise for the sake of losing weight. It might not surprise you to  know that there’s not a lot of evidence that wild animals  exercise specifically to slim down. Geese don’t have Instagram  and TikTok to make them feel self-conscious about their goose bodies.

Lucky ducks... I mean geese. Domesticated animals can get overweight if they’re fed too many treats by their humans – because they are so handsome,  and they all deserve it – but generally, wild animals simply  can’t find enough calories in their day to turn excess  food into excess body weight.

So some overweight pets might  have to hit the kitty treadmill, but that’s still more of a function of human activities than Whiskers wanting to look trim. Even though animals aren’t lining the streets for a race as standardized as an Olympic marathon, they do have their own  long-distance feats. Like migration.

As I talked about in the intro,  bar-headed geese famously expend huge amounts of energy to  migrate across the Himalayas. To prepare for this massive event, they apparently do… absolutely nothing. A group of researchers banded  together from all over the globe to study how these geese are able  to endure such a long flight.

They implanted little devices  inside bar-headed geese to measure the birds’ heart rate,  acceleration, and other body stats to see if anything changed before their migration. After a full year of recording, the geese were recaptured to collect and analyze the data. Overall, the geese’s levels of physical activity didn’t seem to change in  preparation for migration.

In fact, two of the four geese studied showed a significantly decreased maximum  heart rate in the days right before takeoff, so at least  those two were chilling big-time. Even though this study was only  conducted on four individuals, these results could be supported by looking at the physiology of bar-headed geese in general. As it turns out, these geese are especially well suited to handling low oxygen environments.

They have large lungs for their  size, and they take deeper breaths and increase the amount of air they take in high altitudes to offset the thinner oxygen. Plus, their hemoglobin is especially good at binding oxygen for  transport throughout the body, even compared to that of closely related geese. So it looks like this is where  humans are a bit of an oddball.

If you’re a human and you try  to go from couch to marathon in one day without training, that’s  gonna be a fast pass to the ER. But animals are acting in  accordance with their biology– a fruit fly probably isn’t going  to attempt international travel, like Ryan Gosling in The Notebook setting off from South Carolina to Germany, but a monarch butterfly will migrate between Mexico and Canada. Those animals are literally built  diff.

They can just… do the thing. But before we get to the last reason, all science needs funding,  so let’s take a quick break. This SciShow video is supported by Brilliant: an online learning platform  that helps you build real knowledge through lessons  you’ll actually remember.

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Finally, a big reason that humans exercise is just because it’s “good for you.” Regular exercise can improve cardiovascular health and bone density,  as well as boost your mood. Having a gym routine can help maintain your overall physical fitness as you age. But animals in the wild probably  don’t need to be doing all that because they don’t have,  say, an office job to make them sedentary enough to  require exercising on purpose.

Or, they don’t have a steady  enough supply of calories to warrant spending effort  on non-essential activity. Now, in general, there are  very few studies of exercise and voluntary energy expenditure  in non-human animals. However, one researcher, who  did a review on what literature does exist, argued that there  could be a benefit to animals who spend a little extra  effort in fitness training.

The idea is, an animal that trains  to be more physically fit before it becomes necessary to chase down  some prey or outrun a predator will be better and more efficient  at those bursts of activity. The challenge is that any  energy an animal spends on physical activity is energy that  isn’t going towards reproduction. Besides literally staying  alive, producing the next generation is basically top  priority for animals in the wild.

For now, it’s hard to say if this  trade-off is worth it or even takes place at all, because there  aren’t many studies on animals doing voluntary exercise for overall fitness. What studies do exist are all in the lab and take the animals out of their natural context. It’s also possible that there is such a thing as too much exercise for animals.

When you exercise, your cells produce unstable molecules called reactive  oxygen species that can run around and cause damage to DNA and proteins. Kind of like Ryan Gosling in the 2011 movie Drive, driving all around town and leaving  a wake of destruction in his path. Research looking at different  levels of animal activity suggests that moderate  exercise could be beneficial, but too much could lead to a build  up of reactive oxygen species.

So wild animals who are active  near constantly may be increasing their risk of oxidative stress and  lowering their odds of survival. But this review was looking at the  effects in wild animals, and their conclusion was basically “we need  to do more research” so if doing a decathlon brings you joy, I wouldn’t  hang up your javelin just yet. Overall, it seems that animals don’t  really need to exercise in the wild.

But it really begs the question of why we do. If a bar-headed goose doesn’t need to train for a trans-Himalayan flight, it seems  totally unfair that humans need to work out. It could be a byproduct of our  cushy, sedentary lifestyles, or it might be that we have an  appetite for levels of physical capability way outside the realm  of “necessary for survival.” Like Ryan Gosling’s character in  the 2024 film The Fall Guy doing stunt-jumps off a building or  cannon-rolling a car, humans weren’t naturally made to do half  the things we like to do, but we’ve found a way to do them anyway.

For example, there’s an ongoing debate in the fields of biology and  anthropology as to whether or not humans are built for long-distance running. Support for our natural running talent  is shown in our muscle structure. While we might be, on average, mediocre sprinters, our muscle fibers tire out less  easily than quicker species.

This lower power is more  oxygen-efficient, so while other animals can definitely out-speed us,  we’d win over long distances. This trade-off is applied to the  endurance pursuit hypothesis, which theorizes that humans evolved specifically to hunt by winning a battle  of attrition over faster prey. We just stalk them to death.

Another point in favor of  this hypothesis is that humans sweat much more than other  animals during exercise, which helps us release heat very efficiently. Other animals don’t sweat as  efficiently, and without that onboard cooling system, they  overheat and crash out sooner. Not everyone agrees with  this endurance hypothesis.

Firstly, we might be good runners, but running is still far less efficient than walking. Secondly, tracking prey over  long distances and strategically outlasting your target requires a  fair amount of intellectual strategy. No shade to our ancestors, but  some scientists theorize that the mental capabilities required  for such a task simply hadn’t evolved yet in the predecessors of Homo sapiens.

They were no Ryan Gosling in  The Big Short, strategically min-maxing the system to  hoard resources for himself. Plus, early hominids may not have  really needed to be that crafty, given that they were probably already better at finding food than other animals in their habitat. And thirdly, not that many modern hunter-gatherer societies use endurance hunting, at least not that researchers have been able to observe.

If early humans had evolved this  running strategy that was good enough to physically change the  way our bodies evolved, surely this technique would be more  common in modern hunting practices. Researchers supporting the endurance pursuit hypothesis have pushed back on this last point. A pair of scientists from  the US and Canada searched historical accounts of hunting societies and found some evidence of endurance  hunting all over the globe.

Clearly, the book isn’t going to be  closed on this debate any time soon. At any rate, our bodies  have evolved such that we’re able to even consider running a marathon. We have tools, physical and  mental, that make it possible.

Most other animals won’t even come close. In general, it’s hard to put  intentionality to animals’ actions in a way that clearly defines  their movement as exercise. I’ll indulge a little human-centrism  and say that we’re probably the only species that truly exercises,  according to our own definition, as well as maybe the domesticated animals that we cause to behave in certain ways.

So while bar-headed geese  might have us beat in terms of natural ability to summit Mount  Everest, at least any human at the peak can be conscious  of their strategy and skill, and can enjoy the fruits  of their intentional labor. You know, like Ryan Gosling dancing in La La Land. You guys really like Ryan Gosling, don’t you? [♪OUTRO]