Trafficking of wildlife and products such as timber and rhino horn is one of the world's biggest illegal trades, worth £12 billion a year, conservationists have warned.
Species such as rhinos, elephants and tigers are being poached in Africa and Asia, while antique collections, museums and even zoos in the UK are at risk from criminal gangs attempting to steal rhino horn, conservation group WWF said.
Exhibits of rhino heads at Haslemere Educational Museum, Surrey, and Norwich Castle Museum have both been targeted by thieves as criminals seek to cash in on increasing demand for rhino horn as a cancer medicine or "hangover cure" in Asia.
Across the world, illegal trade in wildlife including timber and unregulated and unreported fishing has become a lucrative business for criminal syndicates, with profits that can be used to finance civil conflicts and terrorism, a report for WWF found.
It is also pushing some species to the brink of extinction, hitting local communities in some of the poorest parts of the world and raising the threat of spreading infectious diseases.
The internet is also making it easier for criminals to trade in illegal products around the world, the research by Dalberg Global Development Advisors warned.
Rhino horn is now worth more than £37,000 a kilo, fetching more on the black market than diamonds and cocaine, leading to a surge of poaching in South Africa to record highs last year. It is particularly sought after in Vietnam.
Elephants are also being targeted for their ivory, with poaching across Africa at record levels in 2011.
The animals are being targeted in mass poaching incidents by criminal gangs armed with military issue machine guns, and there have been reports of Sudanese militias including the Janjaweed poaching ivory for profit.