Akiko Hoshino's 17-year-old female Shiba Inu, named Nene, is so old in dog years that she can no longer walk by herself. On the rare days she is out on the streets of Tokyo, Hoshino has to carry Nene everywhere, occasionally a friend helps her wipe the drool from Nene's open mouth. Depending on how you calculate dog years, Nene is around 84 years old in human terms.

"You can't say this is the end to dogs, or any animals, who are trying to keep on living," said Hoshino.

Very much like Japan's growing ageing population, the nation is also facing a large number of ageing pets. Already Japan has more registered pets than children. Some 20 million in comparison to the 16 million children under 15.

When they get too old or sick, while many opt to put their pets to sleep, more and more are choosing to spend money keeping their pets alive until their final days. Some, like Hoshino, have even opted to put their dogs in a special retirement home. At Roken Honpo, which can be roughly translated as "Old Dog Head Office", an average of 10 elderly dogs are taken care of by Mie Kawaguchi and her team. Kawaguchi said she began this business because she saw too many people like Hoshino struggling to care for their elderly dogs and not willing to put them to sleep.

"Simply put: I found out that there were many people were going through this problem, so I thought I would do something about it," she said.

Kawaguchi's staff have their hands full with canine versions of all sorts of ailments – from Alzheimer's to bone and joint diseases, digestive problems and failing eyesight. A local veterinarian regularly checks up on the dogs who are provided with loving care in this centre in their final days.

"Having people and animals interact in this sort of form is good for humans but also for the animals," Kawaguchi added, saying that human care for senior dogs is important.

While the cost of putting your dog in such a home would depend on the dog's size, a mid-sized pooch would set back the owners by 75,000 yen (£473, $660) a month.