‘European first’ as Chester Zoo breeds rare Mexican frogs

Unusual frogs found in the dry forests of Mexico have bred at Chester Zoo – a European first for the species.

The 100 Mexican leaf frogs are the only individuals of their kind ever to hatch in a European zoo.

Amphibian experts at Chester say the successful breeding has unlocked secrets to the frogs’ reproductive behaviour.

Little is known about what makes the frogs tick and, as they have a liking for scorching temperatures that far exceed what most other frog species can live in, herpetologists at the zoo have had to carefully recreate the environment to successfully breed the species.

Adam Bland, Lead Amphibian Keeper at the zoo, said:

“It’s so exciting to have bred these stunning frogs, especially as we’re the first zoo in Europe ever to do so.

“This is breaking new ground for us. The intensive levels of care we’ve put into achieving this successful breeding, coupled with the skills we’ve developed and the details we’ve uncovered about the reproductive behaviour of this species in the process, could be applied to help wild populations if necessary. This information could be vitally important to any conservation action which may be required in the future.”

To encourage the frogs to breed, keepers recreated conditions to closely mimic the hot and dry forests of Mexico, where the frogs come from. 

“These frogs are very, very special. They’re found in parts of Mexico where it’s generally dry for long periods and so they’re adapted to tolerate extremely high temperatures of around 40°C. This would kill many other frogs, but these guys love the heat,” added Mr Bland.

“When it seasonally rains, the frogs spawn and attach their eggs to sticks and plants that hang above ponds. They can lay over 200 eggs in one go. These eggs are transparent and the tadpoles can be seen developing inside before they break out and drop down into the water below.

“Due to the high temperatures in their environment, their ponds dry out rapidly and so they develop incredibly quickly - turning from tadpole to froglet in just five weeks. This is super speedy for a leaf frog, as other species usually take up to a couple of months.

“Their habitat at the zoo has been designed to mirror this as closely as possible and we’re absolutely thrilled that it has resulted in 100 baby frogs.”