Media playback is unsupported on your device Media caption Blended frog drinks are mistakenly regarded as a treatment for disease

Peru is one of the most biodiverse nations on earth. Its weird and wonderful wildlife makes it a hotspot for the illegal trade in live animals - and the country's ecological police are struggling to cope.

Some readers may find parts of this story disturbing.

On a counter at the popular Mayorista market in Lima, stand two small, glass aquariums, containing dozens of toads and frogs. The frogs are from the Andes mountains, and some of the species are endangered. The stallholder works quickly, taking orders from a stream of customers who perch on stools or stand watching her work.

Making a "frog shake" takes a few minutes. First the stallholder grabs a frog from the tank. She cuts its neck with a knife and skins it as easily as if she is peeling a banana. Then she puts it into a pan on a small stove with some liquid. Next the bubbling concoction is poured into a liquidiser with the other ingredients - powdered maca, a medicinal Peruvian root, vitamins, fruit and honey. The stallholder stops the blender and tastes the thick green mixture, her face a picture of concentration. She spoons in more honey, gives it a final whizz and pours it into a tin jug.

"It's very good for anaemia and for chest complaints," says a customer. It is also known as a kind of Andean Viagra. "It's good for that too," he agrees. "But for anyone who's ill, if you take it three or four times a week, you will feel better very quickly."

The amphibian "smoothie" originated among indigenous communities in the Andes, but its popularity has spread. Here, it costs five Peruvian soles - just under $2. "I sell maybe a 100 a day," the stallholder says. And she is well aware some of the frog species are under threat. "We all know that, but well… When they disappear, they disappear. But while we have them, we can help people with this drink."

A couple approach the stall with a small lidded, plastic box. They buy two frogs to take away. The woman explains she will make her own frog shake at home following an old family recipe, and use it to treat a lung complaint.

The stallholder has been fined several times for selling the frog drinks, but she has continued to trade - and customers continue to believe, without any scientific evidence, that the drinks benefit health.

In Peru it is illegal to sell, transport or profit from wildlife. People caught with species listed in the Convention of the International Trade in Endangered Species (CITES) or the corresponding Peruvian decree may be jailed.

"Every day we find five or six listed animals in local markets," says Maj Jose Miguel Ruiz, of Peru's ecological police. "Last week at the airport six drugged toucans were discovered. They had been put in a tube, and were being sent abroad." But in practice prison sentences are rare - Ruiz says there were only seven in Lima last year.

At another market in the north of the city, the Santa Luzmilla market, Ruiz and his team, together with officers from the Forestry and Wildlife Authority, have raided Gladys Permudes' shop. Outside there are baby rabbits and chickens in cages. There is also a sad-looking parrot, and some parakeets - and these are CITES-listed.

The shopkeeper says she paid $50 for the parrot, and is planning to teach it to speak. "I've seen how a parrot becomes an attraction for customers in other shops - I'm not selling it," she says. The parakeets, however, are for sale.

Ruiz confiscates the birds, and tells Gladys Permudes she will have to come to the police station.

It is live trafficking that causes most concern. Peru's myriad species of birds and animals are coveted by collectors both at home and abroad.

Most of this furry and feathered contraband on sale in Lima comes from Peru's Amazon territory, especially the Loreto region.

The Belen market in Iquitos, the regional capital, is a riot of colour, music and smoke. Stalls are stacked with tropical produce, and there is bush meat galore - caiman, jungle deer, and peccary (an animal from the pig family). Indigenous communities in Peru are permitted to hunt for subsistence, but the selling of bush meat is a grey area.

Media playback is unsupported on your device Media caption A BBC team filmed the illegal sale of animals in a Peruvian market

Live animals are also for sale here. A man selling fruit is holding an iguana. He produces a grubby washing up bowl from underneath a table loaded with bananas - in it are turtles, iguanas, and four baby black caiman - an endangered species. He tells a story about one of the big buyers who comes to the market, buys the animals, drugs them, then sends them to Colombia. A woman standing nearby chips in to say she has carried wildlife to Lima in her luggage, and nothing happened at the airport.

Find out more Listen to Linda Pressly's documentary Peru's Wildlife for Sale on Assignment on the BBC World Service, or Crossing Continents on Radio 4. Download the Crossing Continents podcast.

Peru does have a legitimate wildlife business. In the region of Loreto, there are indigenous communities farming turtles and peccary for export. These are projects that enable people to make a living, and encourage conservation. Loreto is also known for its export of farmed ornamental, aquarium fish. But Rainer Schulter, a German biologist and frog expert who has lived most of his adult life in Peru, believes legal wildlife commerce is often a cover for illegal activity.

"They put a false bottom in the tank of aquarium fish for export. Under that, they put frogs, rare turtles, lizards… I would say nearly all illegal frogs travel like that with the fishes."

Schulter says buyers - often Germans, in his experience - buy frogs for $5 from the communities around Iquitos. But collectors will pay at least $100 for rarer species on the international market.

Image caption BBC producer John Murphy feeds a rescued manatee

Image caption A squirrel monkey is rescued from a Lima market

There are some who say the authorities are overzealous in their attempts to catch wildlife traders.

"A hotel here had a caiman skull that was given to the owner by his grandfather well before CITES was in existence," says Richard Bodmer, a British biologist and expert in the Amazon region who has made his home in Iquitos.

"The ecological police confiscated the skull, because they would get funds from abroad if they did confiscations. It's degrading the culture here. Anybody who even thinks of owning an animal is illegal. But this is part of nature."

The Obama administration is concerned about trafficking from South America - the US is the second largest market for illegal wildlife products after China. Recently the government announced the imminent deployment of an officer from the US Fish and Wildlife Service to Lima.

But Bodmer argues that the biggest threat to the Amazon's wildlife - climate change - is being ignored. "This year, two million animals will die from the flooding," he says.

"I see groups coming down here wanting to close everything in Belen market, when their countries - such as in North America - are producing all this carbon which is killing two million animals."

Threats to Peru's wildlife are immense - deforestation, over-hunting and climate change have left their mark. Trafficking is an additional pressure.

At the Ecological Police HQ in Lima, Maj Ruiz has completed the paperwork on his detainees from the markets. One elderly man arrested with two squirrel monkeys has been allowed to go home on account of his age. Gladys Permudes, the shopkeeper selling endangered parakeets, is held for 24 hours and released by the judge the next day.

And it is business as usual for the stallholder making "frog shakes".

"In some cases we make one or two, even 10 visits to shops, and we stop the selling," sighs Fabiola Munoz, director of of the Forestry and Wildlife Authority. "But one month later, somebody opens a new store opposite."

She has one message to anyone thinking of buying a tropical pet or wildlife product that may come from Peru: "If it isn't certified, don't buy it."

Listen to Linda Pressly's documentary Peru's Wildlife for Sale on Assignment on the BBC World Service, or Crossing Continents on Radio 4.

Subscribe to the BBC News Magazine's email newsletter to get articles sent to your inbox.