A new relationship with animals, nature and each other.

New Discoveries about Overweight Animals

Could pollution and viruses be contributing to obesity – and not just pets?

When Prince Chunk passed away last month, he weighed just 17 pounds. That’s a lot for a cat, but a lot less than the 23 pounds he weighed when he was adopted … and a whole lot less than the 44 pounds that he was reported to have weighed when he was rescued in August 2008, and taken to the Camden County Shelter after his 65-year-old person lost her home to foreclosure. (Pictured right, with caregiver Deborah Wright)

Over the next two years, Prince Chunk became something of a national sensation when he made appearances on a series of national TV news shows. And having slimmed down considerably, he became a poster boy for obesity in pets.

Overweight pets are a serious health issue today. About half of the nation’s companion animals — some 90 million cats and dogs — are tipping the scales, according to the Association for Pet Obesity Prevention. Just like humans, they are at high risk for developing diseases such as arthritis, diabetes, kidney and heart disease, high blood pressure and many forms of cancer.

Obesity affecting other kinds of animals, too

But the obesity epidemic appears to be expanding beyond pets and humans, and into other animals. A new report out of the University of Alabama, Birmingham says that many kinds of animals have been getting larger — even in controlled settings like laboratories — which has led to new questions answers about what’s causing this.

David Allison, a statistical geneticist who looked at data from several animal facilities, noted that marmosets at the Wisconsin National Primate Research Center have been gaining weight for several decades, even though nothing much has changed in terms of how they are cared for. In fact, their diet should have been causing them to lose weight, not gain it.

Published in the journal Proceedings of the Royal Society B, Allison’s study revealed that after grouping the animals into 24 different categories of species, environments and genders, he found that animals in every category had been growing increasingly obese.

Viruses and pollution

If this is not simply due to too much food, the wrong food and too little exercise, then what’s causing the problem?

There’s a growing suspicion that chemical food additives and genetic modification of food are implicated. A 2009 study out of the Mount Sinai School of Medicine found that chemicals used in food packaging are linked to childhood obesity. Another study found that human babies exposed to common chemicals before they’re born are twice as likely to become obese.

While Allison emphasizes that diet and exercise are still the prime factors, he notes that environmental toxins and viruses are also among the new suspects. Other studies have pointed toward endocrine disruptors such as BPA and tin-containing compounds. Infections by viruses, specifically a type of the common cold-causing adenovirus, have also been linked to weight gain.

Other recent research suggests that air pollution may be a factor, too. A report in the December issue of the journal Arteriosclerosis, Thrombosis, and Vascular Biology notes that animals exposed to the fine-particulate air pollution of the kind that’s common in the average U.S. city had larger and more fat cells in their abdominal area and higher blood sugar levels than did animals eating the same diet but breathing clean air. The exposure levels for the animals subjected to polluted air resemble the fine-particulate pollution that can be found in urban areas in the United States.

While all kinds of new factors may be contributing to obesity in humans and other kinds of animals, the basic facts haven’t changed: nobody gets overweight from eating good food and burning off the calories they take in. The average female, indoor, spayed, 10-pound cat needs up to 200 calories a day, and the average older, 20-pound neutered dog needs 340-380 calories a day.

Note: Animals used in order to study the effects of pollution were deliberately exposed to polluted air in laboratories. Zoe is opposed to all such experimentation on unconsenting animals. Common sense already tells us that air pollution is bad for them and for all of us.