Goliath builder: why do the largest frogs on the planet build ponds

It turns out that frogs are not so primitive creatures as it might seem at first glance. Behind the simple appearance of a cold-blooded slimy creature hides a very smart animal that can not only catch mosquitoes and larvae, but also build hydraulic structures. For example, in Africa, where the largest frog on the planet lives, scientists discovered unusual ponds that were clearly of artificial origin. Scientists were very surprised by such buildings, but even more they were struck by the fact that they were built by frogs.

Goliath frogs knowingly got such a name - they are really huge. The size of an adult reaches 34 centimeters with a weight of 3.3 kilograms, which makes them the largest on the planet among relatives. These giant amphibians inhabit only one single place on Earth - in equatorial Africa, in the forest in the south-west of Cameroon, as well as in the regions of Equatorial Guinea bordering it. It is humid, and most importantly, very warm: in the forest the temperature is constant all year round, which is just necessary for the development of the offspring of these huge frogs. In addition, there are rivers that they need so much, with a fast flow, in which water is saturated with oxygen. Interestingly, this species of frogs prefers not standing lakes and swamps, namely the river. But, despite its timidity and caution, this species often becomes the prey of poachers and the local population, which uses goliath frogs for food. Due to the intense hunting, the number of huge amphibians fell to critical levels, and the species was listed in the Red Book.

A group of international scientists went on an expedition to the Mpula River basin in Cameroon, in order to better study this species of frogs and, possibly, find ways to preserve the goliath population. Here, biologists discovered more than 20 small ponds that were clearly made by a rational creature. And when eggs and small tadpoles of goliaths were discovered in these ponds, there was no doubt that the builders and owners of these ponds were ingenious frogs. Small depressions in the coastal part of the river, separated by stones from the main channel, look quite natural, but scientists were able to establish that the stones were specially moved, and part of the soil was excavated in order to deepen the artificial pond.

Young tadpoles need a stable and safe living environment, and on the rivers often there are sharp rises in water levels. In addition, an isolated pond protects offspring from predators. Hidden cameras installed by scientists made it possible to find out that Goliath frogs not only construct cozy ponds for their offspring, but also take care of it, coming to a reservoir and driving away predators. For more than two months, frogs have been on duty in turns, which is also very rare among amphibians, who usually do not really worry about the fate of their offspring.