MEXICO CITY (Reuters) - From the live snakes that smugglers stuff with packets of cocaine to the white tigers drug lords keep as exotic pets, rare animals are being increasingly sucked into Mexico's deadly narcotics trade.
Drug gang leaders like to show off rarities like sea turtle skin boots and build ostentatious private zoos at their mansions.
They also reap additional profits by sharing routes with animal traffickers who cram humming birds into cigarette packs and baby monkeys into car air conditioning ducts to be sold to underground pet traders in the United States.
Mexico's raging drug war killed some 5,700 people last year and some cartel leaders have even been rumored to throw rivals to their big cats as food.
The global illegal trade in live species and animal parts -- used for luxury accessories, Asian medicine or folk remedies like aphrodisiacs -- is estimated to be worth up to $20 billion a year, Interpol has said.
The big profits available from selling wildlife on the black market -- where a certain type of endangered South American macaw can fetch $90,000 and a predatory python around $30,000 -- are added incentive to Mexican gangs moving other contraband.
"You can sometimes make as much profit, if not more, than drug smuggling with less consequences, because law enforcement is not paying attention and if you are caught the penalty is just a slap on the wrist," said Crawford Allan, the North American head of wildlife trade watchdog group Traffic.
China and the United States are the largest markets for banned pets and animal products, making the U.S.-Mexico border a busy corridor for the smuggling of many rare species from across Latin America and other parts of the world.
"There is some evidence the same people are trading in both (drugs and animals)," Allan said in Mexico City, where Traffic is helping train inspectors to spot banned animal shipments.
In a major 2007 sting operation by the U.S. Fish and Wildlife Service, the largest of its kind, undercover agents spent three years infiltrating a ring smuggling endangered sea turtle skins from the shores of southern Mexico to as far north as Chicago.
Illegal drugs turned up on both sides of the border over the course of the investigation, U.S. Fish and Wildlife agent Nicholas Chavez said.
In the United States, marijuana was seized at one of the raided warehouses filled with animal skin boots. On the Mexican side, smugglers offered to ship cocaine along with the hides of turtles whose numbers are rapidly dwindling in the wild.
"It was just thrown out there like 'Hey, we can also move this stuff if you want.'... They are pretty much moving anything that they can," Chavez said.
The animals can serve a double purpose when they are used to cover up drug shipments.
"You have cases where there are drugs hidden in false compartments within crates containing live venomous snakes and written on top it says: 'Venomous snakes. Don't open!' So no customs guy is going to want to open that," Allan said.
Bags of liquid cocaine, transparent and only barely visible due to its slight yellow hue, have been found floating in or lining plastic bags containing live tropical fish.
In one shocking case at Miami's international airport, some of the 312 boa constrictors found in a 1993 shipment from Colombia were surgically implanted with condoms full of cocaine weighing a total of 80 pounds (36 kg). All the snakes ended up dead.
Colombian drug lords used to stock their own private zoos with lions, tigers, hippos, venomous snakes and other exotic animals, and Mexico's cartel leaders picked up the same hobby as they took over as dominant players in the cocaine industry.
The head of the Gulf Cartel's feared armed wing the Zetas had two lions and a tiger on his ranch and it is widely rumored, and sometimes printed in newspapers, that he fed the cats with the bodies of cartel rivals.
Mexico's local market for exotic pets is also growing.
Since they breed well in captivity, you can legally buy a tiger in Mexico for a couple of thousand dollars, less than the cost of some pedigree dogs, government officials say.
"It's a show of power and is incredibly common in the criminal underworld. The worst of the worst have exotic animals," Patricio Patron, the head of Mexico's environmental protection agency, told Reuters.
A raid on a drug mansion last year in an upscale Mexico City neighborhood netted a menagerie of two lions, two Bengal tigers, two black jaguars and a monkey -- all of them well-fed and likely tended to by a personal veterinarian.
But not all pets are as lucky as the somewhat tubby big cats, which were sent to a public zoo after the drug raid.
Many smuggled animals do not survive their long, dark, suffocating journeys.
Chavez, the U.S. agent who works along the U.S.-Mexico border, once found nine baby monkeys -- which are usually captured in the wild after their mother is killed -- crammed into a car's air conditioning ducts, most of them dead of suffocation.
Jorge Yanez, a government wildlife expert who runs a shelter for rescued animals in central Mexico, said he once saw four hummingbirds bound and stuffed into an empty pack of cigarettes.
"For every 10 that are trafficked, only one survives," Yanez said at the shelter, which is nestled in a pine forest and works to rehabilitate and release into the wild Mexican species like hawks, wild boars and lynxes that were seized in police raids or handed in by overwhelmed owners.
Editing by Kieran Murray and Philip Barbara