Review of the trade in proboscis monkeys over the last 25 years

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.