A lion and his tigress sweetheart are at odds, right when zoo keepers expect them to conceive a lion-tiger, or liger, said sources at a wildlife park in Hainan.

The 2-year-old lion, Heihei, and 3 1/2-year-old tigress, Huanhuan, were both born in the park, and have shared a pen since April, when zookeepers found they had formed a bond.

Their romantic differences began after Huanhuan was in heat. Disappointed that Heihei did not respond as she had expected, she restlessly paced the floor and at times roared at visitors.

Her would-be lover, however, retreated to the farthest corner of the pen and refused to look Huanhuan in the eye.

Experts say wild tigers and lions cannot mate owing to different living environments. Even when raised together artificially, they rarely interbreed, and the pregnancy rate is very low -- estimated at only one or two percent. Due to the differences in their chromosomes, the rate of survival of their offspring -- which are sterile -- is only one in 500,000.

China's first liger cub was born at Hongshan Zoo in Nanjing, capital of East China's Jiangsu Province, in 2002. But it died just a week later.

A liger was born in September, 2002, and lived for more than 100 days at a forestry park in Fuzhou, Fujian Province.

(Xinhua News Agency December 28, 2003)