The grainy video was released by environmental group WWF which has been monitoring the rhinos for about 20 years in the rugged Ujung Kulon National Park on the southern tip of Indonesia's Java island.

The clips show a mother and calf and a large male wallowing in various mud holes, revealing behaviour researchers had never seen before and helping with the identification of individual animals.

In one clip shot at night, a female rhino chases a wild pig away from her mud hole.

"These rhinos are very shy. In the last 20 years our team has only seen rhinos two or three times with their own eyes," WWF Asian rhino coordinator Christy Williams told AFP.

He said WWF had previously operated still cameras in the dense jungle but the rhinos -- which can weigh 2,300 kilogrammes (5,070 pounds) and measure over three metres (10 feet) in length -- were often frightened by the shutter and fled the area or attacked the cameras.

Under an expanded project to film the animals, 34 cameras with infra-red triggers which take video any time they sense movement in the forest have been painstakingly installed in likely rhino haunts.

Typically they are concealed in trees overlooking wallowing ponds and streams and most of the clips released Thursday show the animals wading or wallowing in mud.

"The videos are showing a lot of young animals but not many calves so even though there is evidence of breeding it is not enough," Williams said.

"A healthy rhino population should be increasing at about seven percent a year or about three or four calves, but here we are getting three or four calves every four or five years."

The WWF is identifying other suitable rhino habitat areas on Java with a view to resettling some individuals from Ujung Kulon to boost their chances of survival.

"This will help diffuse the danger of all the animals living in one place, which is risky because of the danger of catastrophic events like disease, eruptions from nearby volcanoes and other unforeseen disasters," International Rhino Foundation executive director Susie Ellis said.

Adhi Rachmat Hariyadi, who leads WWF-Indonesia's project in Ujung Kulon, said the camera project was helping "the most endangered large mammal species".

"Within a month since the new cameras were installed, we've already recorded video of nine individuals, including a mother and calf," he said.

"We are concerned because we have not seen many very young calves in Ujung Kulon National Park for several years and worry that the population may be dependent on two or three breeding females."

Rhino experts from around the world met in Indonesia earlier this week to discuss plans and progress on protecting rhinos.

"Action needs to be urgently taken because the rhino population has stagnated," Williams said.

Researchers said a smaller population of Javan rhinos in Vietnam's Cat Tien National Park no longer appeared to be breeding.

(c) 2009 AFP