World's largest frogs build their own ponds for their young

AUGUST 9, 2019

The first example of "nest"-building in an African amphibian, the Goliath frog, has been described in a new article in the Journal of Natural History, and could explain why they have grown to be giant.

Researchers observed adult Goliath frogs in the wild and found that they move rocks weighing up to 2kg while building ponds for their young, which they then guard. Goliath frogs themselves weigh up to 3.3kg and their bodies reach over 34cm, without including their legs.

"Goliath frogs are not only huge, but our discovery shows they seem to be attentive parents as well," says author Marvin Schäfer from the Berlin Natural History Museum. "The little ponds they make at the edges of fast-flowing rivers provide their eggs and tadpoles with a safe haven from sometimes torrential waters, as well as from the many predators living there. We think that the heavy work they put into excavation and moving rocks may explain why gigantism evolved in these frogs in the first place."

Despite their renown, they're found only in Cameroon and Equatorial Guinea and little is known about their biology, particularly their reproductive behaviour. Numbers of the endangered species have declined by more than 50 per cent in just 10 years, due to overhunting and deforestation; and researchers first learned about the unusual level of parental care they provide from local frog hunters, who trap adults for bush meat.

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