The illegal trade in exotic animals is a lucrative business, which means gangs must invent increasingly bizarre ways to keep their criminal activities under wraps.While it is virtually impossible to give the exact figure for the value of the underground market, wildlife trade monitors Traffic say it could be somewhere in the region of US$10-23 billion per year. The World Wildlife Fund say the trafficking of rare species is one of largest problems facing wildlife populations today, second only to environmental destruction. Here are some of the ways fly-by-night smugglers have tried in vain to transport tropical and often endangered animals across borders illegally.Native to the Indonesian islands of Bali and Komodo, the yellow-crested cockatoo is regarded as an endangered species – which is why the animal garners such huge demand on the black market. One man no doubt hoping to cash in from sales of the creature was arrested in East Java last year, when he tried to smuggle 22 live cockatoos through Tanjung Perak port in plastic water bottles. The cockatoos were freed from their plastic-encasements, but several of them later died.Vietnam is home to five species of macaque, some of which wound up being carted over the border to China hidden in a cargo of baskets. The long-tailed macaque babies were seized by police from a truck in January 2015. Investigators believed they were intended to be sold on at Changsha, in the Hunan province of China.Sven Koppler was given six months in prison for his efforts to post hundreds of poisonous tarantulas to the US. The German national earned a $4,000 fine for his bizarre scheme, reported Reuters, which saw more than 500 of the creepy crawlers come head into America through the mail. Funnily enough, the crime was rumbled in a US Fish and Wildlife Service investigation dubbed “Operation Spiderman”.The exotic pet smuggling trade took another hit when 81 iguanas were discovered packed into a cardboard box at a hotel in San Jose, Costa Rica. According to Reuters, the animals were released back into the wild after their ordeal.In June 2003, more than 50 tropical fish were saved from likely death while concealed in six specially designed – and highly constrictive – pockets while being transported for illegal sale in Australia. The attempted skirt smuggle was almost the perfect plan, until Singapore airport authorities heard fishy “flipping” noises coming from under the suspect’s waistband.Listed as “critically endangered” by the World Wildlife Fund, the Sumatran Orangutan has been a target for illegal gangs because of its high price tag in the underground market. Baby orangutan’s can sell for around $45,000, say Indonesian conservation group Profauna. Fortunately, three of the young primates were rescued from animal traffickers following a sting by police in Indonesia’s Riau province last year. The animals, all aged under 12 months, were being transported in tiny plastic boxes and were found wearing diapers. Three people were arrested over the illegal trafficking attempt.In July 2012, customs authorities at Ninoy Aquino International Airport in Manila uncovered a plot to illegally fly thousands of baby eels to Hong Kong. The young eels – known as elvers – were found floating into water-filled plastic bags and were destined for the dinner plates of Hong Kong restaurants, reported the Philippines Inquirer.