Visitors to a zoo are playing their part in helping an overweight female African elephant make progress on a diet and exercise regime to prepare it for a groundbreaking attempt at artificial insemination.

Mao, 18, gained some 500 kilograms when put on a special feeding program following the death of her mate in November 2018, and zoo officials have been trying to get her to shed weight to increase the chances of success for what will be the nation's first attempt to artificially breed an elephant in captivity.

Since June 1, visitors to Morioka Zoo in Iwate Prefecture have been helping to get Mao to walk back and forth between both ends of the enclosure by offering food such as bananas and apples on a long pole over the fence. She makes the 60-meter journey up to 15 times a day.

The elephant weighed 3,940 kg as of June 20, down about 210 kg from late January, but her target weight is 3,600 kg.

After the death of her mate, Taro, at the zoo a year and a half ago, Mao initially lost her appetite, but zoo officials responded by giving her higher calorie food to keep up her weight, resulting in her piling on the pounds.

While it is hoped slimming down will help Mao experience a safe delivery, overdoing it could be harmful, too, the zoo said.

"We will closely monitor Mao's health condition and be creative with her menu and the number of feeding times," a zoo official said.

"I am looking forward to Japan's first baby elephant to be born through artificial insemination," Hiroki Matsumoto, a 44-year-old local dentist, said June 21 as he watched his daughter Iroha, 5, give an apple to Mao.