Animals in the Wild Are Getting Fatter Too?

Definitely some mind blowing things to think about with this one!

It’s Not Just All of the People Around You That Are Getting Fatter

And some wild animals are getting bigger, too. Body weight in male rats in Baltimore increased 5.7 percent between 1948 and 2006. Even rural rats have gained weight. Body weight of male rats trapped in the Maryland countryside increased by 4.5 percent.

Animals are getting fatter, just like humans, “even in the absence of those factors that are typically conceived of as the primary determinants of the human obesity epidemic via their influence on diet,” according to the “Canaries in the Coal Mine” study. Animals don’t have access to vending machines and they aren’t playing PlayStation 3, but they’re still starting to look like those fat-people’s-butts-walking-on-city-streets shots that always seem to accompany mainstream news stories about human obesity.

The change here is something of a mystery but it may reflect what we see in human lives, too. Americans, after all, eat poorly, but even people in Japan, where diets are some of the healthiest in the world, are getting fatter. People everywhere, in fact, just weigh more than they used to, despite the fact that they don’t all consume large amounts of high fructose corn syrup and have the sedentary jobs of people living in America or Western Europe. What’s going on? No one really knows.

According to the Allison study: One set of putative contributors to the human obesity epidemic is the collection of endocrine-disrupting chemicals (endocrine-disruptors), widely present in the environment. Another conceivable explanation is obesity of infectious origin. Infection with adenovirus-36 (AD36) leads to obesity in multiple experimental models and antibodies to AD36 are correlated with obesity in humans. These observations suggest that AD36 and conceivably other infectious agents could be contributing to obesity within populations.

Other explanations may include epigenetic-mediated programming of growth and energy-allocation patterns owing to any number of environmental cues such as stressors, resource availability, release from predation or climate change. Basically, the environment could be to blame.

The widespread presence of chemical carcinogens in nature may not only be giving us cancer, it might also be making humans—and animals—obese. Certainly the fact that animals (pets, captive, and wild) are getting fatter even without doing or eating the things that are supposed to be making people so overweight indicates that something strange is going on here.

As David Berreby writes at Aeon, however, it’s possible there’s actually some mysterious other thing going on here, something unknown and hidden. Humans sweat and shiver to maintain the appropriate body temperature. The things our bodies do naturally to maintain temperature burn calories. Now that we increasingly live and work in climate-controlled environments, our bodies don’t need to burn as many calories to keep the right temperature.It’s reasonable to suppose that pets, zoo animals, and even rats would be impacted by this as well, since they live mostly in climate-controlled, human-built environments.

All of this is not to say that the basic narrative of the Western World’s gut—that we’re becoming overweight because we eat poorly and don’t exercise—is wrong. Certainly if you weigh too much the only good way to shed the pounds is to improve your diet and be more active. But it’s possible that the true story of fat might be more complicated, and not just a function of lifestyle. Look to the animals.