This is the first time that researchers have captured an image of a female Sumatran rhino believed to be pregnant.
There are so few of these animals left in the wild - possibly no more than 30 on Borneo - that experts say each new calf is a lifeline for the species.
The female is thought to be around 20 years old, and the researchers have set up some 50 cameras in the area to try and track her movements.
If she is indeed pregnant - and the experts say they can't be sure yet - the birth of a calf would go some way to allaying fears that the rhinos have become so isolated from each other, they are not even meeting to breed.
The location of the rhino is being kept secret, as this is an area where poaching, and also illegal logging, are a huge threat.
The Sumatran rhino is an extremely shy creature which is rarely seen.
Researchers are trying to gather more information on the health and condition of the species through the use of remote cameras.
There was excitement recently when the cameras caught images of two young rhino in the area where the female has been spotted.
The World Wildlife Fund is working with local officials to produce an action plan to protect forest reserves, and to rescue rhinos where necessary to help them breed.
in the wild:在野外
calf:幼仔
lifeline:生命線
track her movements:跟蹤她的行蹤
allaying fears:減少擔(dān)心
breed:繁育
poaching:偷獵
illegal logging:非法伐木
World Wildlife Fund:世界野生動物基金組織
action plan:行動計劃