You don't want this grocery bill

Happy is a 27-year-old Nile hippopotamus at the National Zoo. Feeding time for him is also behavioral training time, which makes medical exams easier. Animal keeper J.T. Taylor has worked with him for years.

The 6,000-pound hippo consumes seven pounds of herbivore pellets, 41/2 pounds of fruits and vegetables and 35pounds of hay each day.

Wild hippos consume as much as 88pounds of grass per night, but as a percentage of their body weight (1 percent to 1.5 percent), that's only about half the amount required by other hoofed mammals. Native to sub-Saharan Africa, Nile hippos graze in short grasslands by night and conserve energy by wallowing in lakes, rivers and wetlands during the heat of day.

Other facts about zoo food:

Fewer than 10 percent of the country's 220 accredited zoos and aquariums have nutritionists. The National Zoo has two.

The National Zoo is the only U.S. zoo to grow its own hay, farmed on 190 acres at its Conservation and Research Center in Front Royal, Va. This allows the zoo to control the types of hay grown and the methods of fertilization.

The zoo also grows bamboo at the center and at two private locations in Fairfax, Va., and Fort Washington, Md. The zoo's giant pandas alone get 1,400 pounds of bamboo a week.

Here is a partial shopping list of food the National Zoo buys or grows each year: 15,000 pounds of leafy greens, 6,000 pounds of apples, 1,750 pounds of grapes, 2,000 pounds of oranges, 6,000 pounds of bananas, 2,000 pounds of papayas, 3,500 pounds of carrots, 4,000 pounds of sweet potatoes, 2,500 pounds of green beans, 1,200 ears of corn, 5,400 eggs, 93 tons of dry feeds, 32,500 pounds of frozen carnivore diet, 20,000 pounds of frozen fish, 8,000 pounds of beef bones and oxtails, and 4 million mealworms.