Tama Zoological Park in the western Tokyo suburb of Hino boasts 420 animals representing 59 species, including elephants, lions and giraffes, and cleaning up after them is a tall, costly order.
Tama Zoo's animals together generate some 1,060 tons of droppings annually, which cost 30 million yen to dispose of.
The Tokyo Metropolitan Government, which runs the zoo, recently adopted a plan to recycle the dung in the form of biomass energy to cut disposal costs and save on the use of fossil fuels.