The Lake Titicaca frog was given the unfortunate nickname because of the saggy folds of excess skin which it uses to absorb oxygen from the water at the bottom of the lake, on the border of Bolivia and Peru.

Twenty of the rare frogs have gone on show to the public for the first time at Chester Zoo, where conservationists are studying their behaviour in the hope of helping to save them from extinction.

The zoo was the first in Europe to give a home to the species, listed as endangered by the International Union for the Conservation of Nature (IUCN), and has established a European population by sending 130 frogs to 13 other zoos across the continent.

Between 50% and 80% of the frog population has been lost from Lake Titicaca in the last 20 years due to a combination of pollution, habitat loss and hunting, experts said.

Chester Zoo has teamed up with the Cayetano Heredia University in Peru and the Natural History Museum’s Alcide d’Orbigny in Bolivia to form a union to help save the frogs and secure the future of the lake.

Dr Gerardo Garcia, the zoo’s curator of lower vertebrates and invertebrates, said: “We’re very happy that we can now share our efforts to protect these frogs with the wider public, who will most likely be seeing them for the very first time during their visit the zoo.

“What we need to do now is to build on our knowledge of the species and its biology – by learning all about their life cycle, mating behaviours, favoured habitat and ability to tolerate or resist a deadly fungus that is wiping out lots of amphibians, called chytrid.

“We can then harness that valuable information for conservation action in the wild.”

Dr Garcia said people in Peru and Bolivia were known to harvest the frogs, despite it being illegal, and use them in smoothies which they believe enhance virility and energy.

He added: “The planet is facing its biggest ever biodiversity extinction, with thousands of amphibian species at risk of being lost forever.

“Human activity is very much part of the problem, but we won’t sit back and let them become extinct because we’re also key to the solutions and will play a vital role in reversing the damage.”

Roberto Elias Piperis, co-ordinator of the wildlife laboratory at the Cayetano Heredia University in Peru, added: “This species is unique. It is only found in Lake Titicaca and the surrounding areas where it is adapted to the very adverse conditions there.

“The lake is at extremely high altitude, nearly four times as high as the summit of Mount Snowdon in Wales and, in addition to its ecological importance, there is also a cultural one, because the local inhabitants consider the frogs as a connection between them and the gods so they use them in rituals to call rain.”

The frogs can grow up to 20 inches long and weigh almost a kilogram.