Despite the popularity of koalas, the number of those kept in Japanese zoos has been more than halved from the mid-1990s peak as their population continues to grow old.

The difficulty of accommodating their fussy eating habits — they feed exclusively on eucalyptus leaves, which are expensive to grow in Japan — is also overshadowing their future in this country.

The first koalas arrived at Japanese zoos in 1984, with the number rising to nearly 100 by 1997, living in nine zoos. Since then, their numbers have continued to dwindle, falling to around 40 at present.