A baby giant panda born at a zoo in Tokyo last week has died, probably from pneumonia¹, zookeepers have said.

上周在东京某动物园出生的大熊猫幼仔已经死亡，饲养员称可能是死于肺炎。

Shin Shin with her baby just days after keepers realised she was pregnant
The male cub², which had not been named, was just six days old and was found lying on its back on its mother's chest.

It was the first time the zoo's natural breeding programme had been successful, and the birth had been widely celebrated³ across Japan.

The cub's parents, Shin Shin and Ri Ri, arrived on loan from China last year.

Tokyo pays $1m a year to lease（租得） them.

Six-year-old Shin Shin gave birth just days after being declared pregnant. The arrival was the first in the country for more than 20 years.

Pandas often experience difficulty in conceiving naturally, particularly when they are on public display, according to experts.

The baby had been kept in an incubator（早产儿保育器） earlier this week, but had been returned to its mother on Tuesday.

When it was found, it was not breathing. Keepers at Ueno zoo massaged⁴（按摩） its heart, but the cub was declared dead an hour later.

China often loans pandas to other countries as gestures of friendship and to take part in breeding programmes, but asks that all pandas and their offspring are eventually returned to China.

About 1,600 remain in the wild in China, with some 300 others in captivity⁵ - mostly in China.

Shin Shin and Ri Ri appeared for the first time in public shortly after a powerful earthquake and tsunami⁶ struck Japan on 11 March 2011.