Even when the rest of the family has gone green, Fluffy and Fido are often left to wreak a surprisingly massive toll on the environment. The estimated 10 million tons of waste produced each year by dogs and cats have a particularly devastating impact: Unbagged excrement can contaminate groundwater and soil with disease-carrying bacteria and parasites, while bagged waste stagnates in landfills. Meanwhile, pets are often exposed to dangerous levels of toxins because of the food and product choices we make for them. A 2008 study showed that dogs' and cats' toxic loads are often substantially higher and more varied than those of their human owners. So how can you take care of your pets and Mother Nature? Here are four ways to start.

Tip #1:Make their toys...