Interesting: Animals are getting fatter, too

[salvorhardin]

If it were just dogs and cats, I might suspect that pet owners accustomed to larger portion sizes were just super-sizing their doggy dinners too, but this is a much larger number of species which does indeed suggest something environmental.

All 24 populations of animals, which ranged from primates housed in research facilities to feral rats living in the greater Baltimore area, showed significant increases in body weight. Average body weights of captive chimpanzees increased at a rate of 33 percent each decade, and 9 percent per decade in captive marmosets. Laboratory mice got 12 percent fatter every ten years, laboratory rats did by 3 percent; the average body mass of Baltimore's feral rats increased by almost 7 percent each decade. And house pets were no exception, either. The average weight of cats increased by almost 10 percent each decade, while dogs' weights increased by 3 percent every decade.

Not only did body weight increase significantly, but so did the chances than an animal would be obese. In 23 out of the 24 populations, animals were more likely to be obese -- defined as weight above the 85th percentile at the initial time-point -- at the second time-point than at the first.

What's more, the increased body weights and increased likelihood of obesity were found even in animals whose diets and physical activity levels were known to be the same throughout the study period. So if dietary changes and energy imbalance weren't responsible for the rise in obesity, said Allison, it may be some environmental factor.

"If we're seeing these trends in other mammals, it shows that there must be another explanation" besides the main culprits of inertia and poor diet, Kuk said.

Full article: http://www.the-scientist.com/news/display/57821