BEIJING (AP) _ A pair of rare white rhinos on loan from the San Diego Zoo died after five days in an open truck in western China, the apparent victims of heat and dehydration.

Until the Chengdu Zoo can borrow another rhinoceros, it is trying to stuff one of the ones that died for display, Song Yunfang, an animal expert at the zoo, said today.

Neither the Chengdu nor San Diego zoos publicized the deaths in July of the white rhinos, two of about 6,000 worldwide. China's tightly controlled official media hasn't reported the deaths either.

The rhinos were supposed to travel 1,200 miles from the eastern port of Shanghai to central Chengdu city by rail or boat, but instead the caged animals were put in an open-bed truck during the hottest part of summer, on July 17, Song said.

Five days into the trip, the fully grown male and female rhinos died in 99-degree heat in Qinling, a small city a day or two drive from Chengdu.

``We were all very sad and sorry,'' Song said by telephone.

No autopsy was conducted because of the poor state of the corpses, Song said, but the zoos suspect heat and dehydration killed the animals.

The San Diego Zoo, famed for its exhibitions and expertise and relatively well-heeled, did not send specialists with the rhinos from Shanghai to Chengdu.

The Chengdu Zoo, cash-starved like most Chinese zoos, did not stick to an agreed-upon plan for rail transit, San Diego Zoological Society spokesman Tom Hanscom said.

The two zoos have a cooperative relationship: Hanscom said Chengdu asked for help in locating a pair of rhinos five years ago.

The pair, who were not named, were found at the Pittsburgh Zoo, and San Diego bought them for $3,000.

Chengdu's airport is too small to handle Boeing 747s, the only commercial plane with cargo space large enough to transport the rhinos, their cages each about the size of a mini-van.

Song said by the time the rhinos arrived by air in Shanghai, two weeks later than expected on July 16, the Chinese summer had entered its hottest period. Summer rains had swollen the Yangtze River and caused long delays for boats passing through the locks at the Gezhouba dam, Song said.

The rhinos' cages did not fit into rail cars arranged for the trip, she said, so zoo officials settled on a truck.

``At the time, air-conditioned trucks were scarce, and we thought, since they were tropical animals, they should have no problem withstanding 85-degree plus temperatures,'' Song said.

In San Diego, Hanscom said that prior to the trip Chinese officials had given assurances that the rhinos would fit in the rail cars and trained personnel would care for them.

Shanghai Zoo officials even cabled San Diego on July 17, saying the rhinos arrived in good health, he said.

``They were on the road in the summer and apparently did not receive sufficient attention during the transport,'' Hanscom said.

``Transporting a large mammal that distance is always somewhat difficult, but not impossible if the animals receive proper attention,'' he said.