Researchers based in the U.S. used information collected on the weight of more than 24,000 fully-grown individual animals from numerous scientific studies across the world. Their study included animals that live with humans in a variety of settings – including pet cats and dogs, captive chimpanzees, feral rats and laboratory mice. Despite the range of species studied and the circumstances in which they live, every single species studied experienced an increase in their average weight over time.
While this might be attributed to pampered pets or feral rats living off discarded junk food, the fact that even laboratory animals – who tend to live on strictly controlled diets – are getting fatter suggests that some hitherto-unconsidered common factor may be leading to increased obesity in all of the animals studied, including humans.
As Yann Klimentidis, one of the study’s authors, states: “When looking for ways to combat obesity in humans, we need to be more aware of all the possible alternative causes of obesity. If we can find causes for the weight gain seen in our animal subjects, we may be better able to apply that to coping with obesity in humans.”