Mountain chicken frogs: 'World’s most threatened frogs' welcome clutch of baby froglets at London Zoo

London Zoo is celebrating a conservation success story, after two of its critically endangered 'mountain chicken' frogs successfully raised a clutch of tiny froglets, for the first time in five years. 

Also known as the giant ditch frog, mountain chickens are huge frogs native to the Caribbean islands of Dominica and Montserrat. Adults tip the scales at a whopping 360g, almost as much as a can of soup. But the species is in serious trouble, and its numbers have been plummeting since the 1980s - initially due to human consumption and habitat destruction.

But in the early 2000s, a team of scientists - including one from the Zoological Society of London (ZSL) - discovered the frogs were in the middle of a mass mortality event caused by the deadly chytrid fungus, which the zoo said wiped out more than 90% of their population.  A recent intensive survey to find the frogs in Dominica identified just 21 individuals.  

In 2009, conservationists from London Zoo and other European zoos airlifted the last few mountain chicken frogs to safety in a last-ditch attempt to save the species from extinction - and a coordinated breeding programme was developed for the species. Metamorphosing just in time for Mother’s Day, London Zoo's six new froglets represent hope for the species' future.

The clutch is the offspring of a new frog pair, which recently moved into the zoo’s newest habitat - the Secret Life of Reptiles and Amphibians centre - which will open this Easter. This will be the first time London Zoo's mountain chickens will be visible to the public.

The zoo said once the gigantic duo arrived, they immediately got to work prepping for parenthood, with the huge male quickly digging a ‘bowl’ in the underground clay-lined nesting chambers, showing off his skills to his new mate. The pair then began the hard work of prepping to welcome their offspring - producing a foam nest to lay their eggs into.

Mountain chicken tadpoles develop inside the foam nest and, uniquely, their mother lays thousands of unfertilised eggs for her offspring to feed on every one to seven days, to make sure her babies have the best start to life. She may lay as many as 25,000 eggs for them during this period.

ZSL’s reptile and amphibian curator, Ben Tapley said: “We are delighted at how quickly the mountain chicken frog colony have settled into their new home. Soon after they arrived, we spotted the female frog guarding her foam nest. 

"Mountain chicken frogs are incredible parents. The mother regularly visits the nest to lay unfertile eggs, which the growing brood will feed on, she also guards her nests, puffing up and using her body to defend her young from anything that gets a little too close," he continued. 

The six, inch-long froglets still have some growing to do to reach their enormous adult size, he added, and would have an important job to do to help bring their species back from the brink of extinction.