China's giant pandas may be getting a hand from their North American cousins as well as orangutans, tigers and elephants.

The panda population in China is "still very vulnerable", and needs help, according to US researcher Ben Kilham, who will be featured in the new IMAX 3D film Pandas, scheduled for release in April.

The movie was made in cooperation with the Chengdu Research Base of Giant Panda Breeding in Southwest China's Sichuan province and directed by Drew Fellman, a producer and writer who previously worked on the documentaries Born to Be Wild (2011) and Island of Lemurs: Madagascar (2014).

Kilham, well known for his work with black bears in his home state of New Hampshire, has been working to see if his success in introducing captive-born black bears into the wild can be applied to pandas in China.

"We have raised and released into the wild about 165 black bear cubs," Kilham said.

Kilham has been doing research on black bears for about 25 years. Giant pandas and black bears are different species of bears but have similar characteristics and behavior patterns.

"They are both large omnivores - which means they eat plants and animals," said Kilham.

One of Kilham's major success stories involves a black bear named Squirty, who came to him when she was just 7 weeks old. Now 22 years old, Squirty "recently gave birth to her 11th litter of cubs in the wild, and I still have access to her", he said.

Kilham presented his work on the introduction of captive-born black bear cubs into the wild several years ago at a conference on the effects of climate change on panda habitat. "This interested the Chinese scientists," he said.

The Chengdu panda center says its researchers were surprised that Kilham had released into the wild as many as 165 black bear cubs and wondered if his experience would be useful with pandas.

But a researcher at the Chengdu center also pointed out the differences between giant pandas and black bears.

Pandas normally do not attack and eat other live animals. There are only reports of pandas feasting on dead animals, said the researcher who asked for anonymity.

Digital photos taken in late 2011 with an infrared camera in a forest in Sichuan's Pingwu county showed a panda eating a leg of a dead adult antelope that had been trapped between rocks in a ravine. The county is near the Baishuijiang Panda Nature Reserve in neighboring Gansu province.

Pandas were meat-eating animals several million years ago. As a result of changes in the environment, they changed their diet and began to eat mainly bamboo.

Before meeting Kilham, Chinese researchers preparing to release pandas had also learned from the experience of others who had reintroduced orangutans, tigers and elephants into the wild.

Those experiences also influenced Kilham's methods with black bears, the researcher added.