The Bronx Zoo now has eco-friendly toilets, because saving wildlife and your bowel movements are intimately connected. At 1,200 square feet, the The Eco-Restrooms  are designed to maximize the use of daylight and minimize electricity. Instead of conventional flush toilets, which use nearly two gallons of water with every thoughtless flick of the handle, these are composting toilets, which use 99 percent less. The three ounces of water that are used go into a composting tank below the building where the creatures you can’t visit at the zoo transform your waste into usable fertilizer. Though they would never urge you to forgo washing your hands in the name of saving the planet, that water is then used to irrigate an adjacent garden where plants help clean and filter it. Find the fancy commodes at the Bronx River parkway entrance, which is used by 60 percent of the two million people who visit the zoo each year. Together, you can make a difference.