web analytics

World’s Heftiest Frogs Use Muscles To Lift Rocks And Build Nursery Ponds For Their Spawn

Goliath frogs: Skilled diggers and A-star parents. Credit: Marvin Schäfe

The Goliath frog is an amazingly impressive creature just considering its size alone. From its name, you could think it is a big beast whose weights could be 3.3 kilograms (7.3 pounds) with  lengths greater than 34 centimeters (13.4 inches) not including the legs. 

However, some researchers have found a new characteristic of such frog, which is equally enthralling. That is – the frog can build ponds for its young. This is the first example of “nest-building” in an African amphibian. As a matter of fact, scientists suspect that due to such behavior, those frogs could grow to such a large size.

According to Marvin Schäfer, researcher from the Berlin Natural History Museum, Goliath frogs are not only big, but also quite attentive as parents. The little ponds they make at the edges of fast-flowing rivers could offer their eggs and tadpoles a safe haven from sometimes torrential waters, as well as from the many predators around. It is suggested that the heavy work they put into excavation and moving rocks might give explanation about the reason that gigantism evolved in these frogs in the first place.

Schäfer and his team discovered this curious habit by application of infrared time-lapse that had been set up to watch the nest. They had found three nest types of differing complexities in the case. The first was a quite simple job of clearing leaf-litter and debris from naturally occurring rock pools. These were in stark contrast to the surrounding puddles containing a layer of leaves, debris, and gravel.

As for the next step, the frog was required to form a dam with the leaf litter and gravel by digging it up and pushing it to the edges. The third required the frog clearing shallow water depressions of large stones weighing up to 2 kilograms (4.4 pounds) and moving them to create a dam around the pond’s edge. This was the most effective way of  preventing overfill or flooding.

When the pond was finished, a frog would stay alert, watching over their young at night to stop any predators that would be too close. Their shift would be completed just before dawn.

As Mark-Oliver Rödel, project leader and president of Frogs & Friends, said, the fact that scientists had just recently discovered these behaviors demonstrated how little mankind knew about even some of the most spectacular creatures on the Earth. It was  hoped that these findings, together with further ongoing research, would help a better understanding of the needs of the Goliath frog so more support would be given to its continued survival.

Hopefully, it’s not too late. The range of the Goliath frog is limited  to Cameroon and Equatorial Guinea, but overhunting and deforestation have made the numbers of those frogs sharply drop  50 percent in just 10 years. In order to protect their existence, IUCN has categorized them as endangered on the its red list.

Baby Goliath. Credit: Marvin Schäfe