agreed grant.
the habitat in vietnam is less than ideal. so taking the breedable vietnamese animals (if any) to java might be a smarter option.
Patrick- at present there's one viable(Java) and one non viable(Vietnam) population for this species. I think a 2nd viable population would be a very good thing to set up to avoid total catastrophe e.g. a Tsunami or other natural disaster/disease/ whatever wiping the single viable population out.
I don't know if capturing a pair or so to go to zoos, or better still, a secure reserve is a good insurance option, or not- however I have a feeling that if successfully captured(the tricky part) they would settle down and be basically quite easy to manage in confinement- like their very close relative, the GI Rhino. (Sumatrans are completely different and as we know have not adapted well to captivity at all)
I should have thought translocating the 2-10 scattered Vietnamese animals in Cat LOc(?) to a safer place might be the best option- if, as is believed, no male was found during this operation, then add one or two from Java.
Did you know Adelaide Zoo had at least one Javan Rhino many years ago? I've seen a photocard of a keeper feeding it....