Posted by 
I am an ecologist, and I have been lucky to work with white rhino in Africa. This work has involved capturing rhino, dehorning and moving them – methods used to try to save rhino from poachers.
Poachers target these large, plant-eating mammals for the illegal trade in rhino horn, fuelled by demand from Asia, principally China and Vietnam, where the horn is perceived as a status symbol, a cure for illness and an aphrodisiac.
Poaching is the main threat to the African rhino, but it was not considered a risk for the critically endangered Javan rhino in Asia. So rare and difficult to detect are Javan rhino, which live in dense jungle, that it was thought poachers would not be able to find them.
However, recent testimony from poachers arrested in Indonesia has indicated that 26 of the estimated maximum 72 Javan rhino have been poached by two gangs in the last five years. That is shocking news.
This revelation turns a worrying situation into an emergency – and demands increased efforts to save the Javan rhino from extinction.
How many Javan rhino are there?
Indonesian police arrested 13 members of two poaching gangs who revealed the otherwise undetected loss of rhino from Ujung Kulon National Park, the home of the world’s only remaining Javan rhino population, on the island of Java in the Indonesian archipelago.
Javan rhino were once widespread in southeast Asia. The last one outside of Indonesia was poached in Vietnam in 2010.
The actual number of rhino killed by the poaching gangs cannot be verified. It’s possible that sources within the government or conservation teams are passing information to poachers.
Indonesia’s forests are home to 10-15% of the planet’s plants, birds and mammals. While Indonesia harbours the greatest amount of rainforest in Asia, over 74 million hectares (three times the land area of the UK) have been lost in the past 50 years to palm oil extraction and paper mills.
Indonesia’s forest cover has fallen from 80% to less than 50% amid one of the fastest deforestation rates in the world. Pandeglang, the Javan region containing the national park, has lost nearly 10% of its rainforest since 2000.
All scientists know about the abundance of Javan rhino is gleaned from camera traps, remote cameras that are triggered to take photos by passing animals. The last government population estimate was released in 2019.
A report published in 2023 criticised this estimate because 18 of the rhino counted had not been detected by a camera trap for three years, and three of the rhino counted were known to be dead.
Saving the Javan rhino from extinction
Indonesian conservationists have focused on habitat loss as the leading threat to Javan rhino, as it deprives the species of breeding opportunities. Scattered across separate fragments of jungle, rhino are unlikely to find each other during the brief window when females are receptive to mating.
There is also evidence of inbreeding, exacerbated by there being more adult males than females. Some biologists have called for Javan rhino to be taken into captive breeding programmes.
With just 46 Javan rhino in the wild (perhaps even less), poaching could wipe out the species or reduce it to such a low number that low breeding success deals the final blow.
So, what now? It is likely that the Javan rhino cannot afford to lose any further animals to poaching, and vital that further poaching is prevented. The Indonesian government has now increased security in the national park with police and military combining forces.
Allowing forests to naturally regenerate and planting corridors of trees between jungle patches will help the remaining rhino find suitable habitat and each other. Conservationists have also called for cutting down trees in some locations to allow fresh, young trees with more accessible leaves to grow.
Research has also shown that removing an invasive palm boosts the availability of rhino food plants. Livestock must be excluded from the park too, as domestic cattle can transmit disease.
As far back as 1986, conservationists called for some rhino to be moved out of the park (perhaps to the neighbouring island of Sumatra). Splitting an already limited population is risky, but not establishing the safety net of at least one other population elsewhere is riskier still.
What if a tsunami hit the park? And the park may already be near capacity, as it is estimated to be able to support only 68 rhino.
Bringing Javan rhino into captivity and using reproductive technologies on stored eggs and sperm (techniques in development for the more common white rhino) may also need to be considered. Although, it is still possible that captive breeding may not be required: camera traps have photographed newborn Javan rhino, as well as adults, as recently as March 2024.
Scientists don’t know much about Javan rhino biology. There have been few studies of wild rhino and only 22 have ever been kept in captivity, the last of which died more than 100 years ago. More research is needed to understand as much as possible about Javan rhino ecology and reproduction – in the wild and from museum specimens.
More effective habitat and wildlife conservation across Indonesia will benefit other Indonesian species, including the Sumatran tiger, Sumatran elephant, all three species of orangutan, and the Sumatran rhino (estimated population of 24-47, making it the world’s most endangered rhino).
If effective conservation action is not taken now, the remaining Javan rhino population will go the same way as that in Vietnam.
Don’t have time to read about climate change as much as you’d like?
Get our award-winning weekly roundup in your inbox instead. Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 35,000+ readers who’ve subscribed so far.
Jason Gilchrist does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
