Review of the trade in proboscis monkeys over the last 25 years
Bibliographic record
Abstract
Proboscis monkeys Nasalis larvatus are endemic to the island of Borneo (politically shared between Malaysia, Brunei Darussalam and Indonesia) and are threatened by habitat destruction, fires and hunting. Because of their specialised diet, they are very challenging to maintain in captivity and in the past live trade was not seen as an impediment to their conservation. We report on and review the trade in proboscis monkeys over the period 1999–2024, based on published literature, media reports, seizure records, court rulings and communication with experts. We found no records for Malaysian Borneo or Brunei. We found 25 reports in the Indonesian media (concerning 52 proboscis monkeys), mostly from after 2016, and mostly from the province of South Kalimantan (14 reports) but also from the islands of Sulawesi and Java, both gateways for export and neither within the natural range of the species. In 2024 one proboscis monkey was seized in Mumbai, India, coming from Indonesia. Proboscis monkey skulls were found in trade in wildlife shops in Bali in 2022–2025, specifically targeting foreign tourists. Online traders in Sumatra, Kalimantan and Java were found offering at least 48 proboscis monkeys for sale. Between 2016 and 2024, 14 people were prosecuted in Indonesia for trading, transporting or keeping a total of 42 proboscis monkeys, receiving a mean fine of USD1,795 (out of a possible maximum of USD6,150) and a mean sentence of 13 months in prison (out of a maximum of 5 years). Prior to the turn of the century there were very few proboscis monkeys in zoos, but in recent years this has changed, and now there are at least 74 individuals in 10 Indonesian zoos and 2 individuals in a Malaysian zoo, in addition to at least 31 individuals in zoos in Singapore, China and Japan. Our review shows that not only are zoos increasingly acquiring this species but that proboscis monkeys are also increasingly available in the illegal wildlife trade. We urge the authorities, especially in Indonesia, to increase the efforts to enforce existing legislation and to be more active in their efforts to curb the trade in these globally threatened primates.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.010 | 0.011 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".