Some one billion frogs are gobbled up each year. Around since the dinosaurs, some frog species are nearing extinction, warns a leading German biologist.

(Tom Harding)

  

Anita Pöhlig,

 

BRAUNSCHWEIG - The diversity of frog species is rich and vast. Some weigh six pounds, others are smaller than a thumbnail, there are frogs of an inconspicuous gray shade and others that light up in the most vibrant colors - in sum, more than 6,000 species of frogs are known to mankind. Miguel Vences knows almost all of them.

 

"Frogs were already jumping around with the dinosaurs," says Professor Vences, a biologist at the Technical University of Braunschweig in Germany, and one of the world's leading researchers of these croaking amphibians. 

 

For the past 250 million years, frogs have managed to survive on their own. But today, amphibians in many countries are seriously threatened with extinction. "In France and Belgium, but also in the United States, frog legs can still be found on many menus. To support that luxury, many frog habitats are being destroyed in Asia," Vences says.

 

In China and elsewhere in Asia, frogs have now become a source of food, while the threat of famine in Africa has helped introduce frog into eating habits there. Vences estimates that more than a billion frogs are eaten every year worldwide.

 

In addition, a dangerous fungus has begun to attack the skin of frogs in recent years, causing many populations to die out. It is still unclear, however, whether it is the chytrid fungus that is directly causing frogs to die in such great numbers, or whether these animals are dying due to other stresses on their environment or their resulting immune system failures. "This fungus is also present in Germany, but our frogs do not seem to be suffering from it on a large scale," explains Vences.  

 

"I started looking for frogs in ponds as a kid," recalls Vences. At that time, scientists did not yet know many frog species. Vences and his colleague Frank Glaw alone have discovered and scientifically named some 100 species.

 

The two have conducted research together since the 1980s - when they were still students - primarily in the jungles of Madagascar. Vences and Glaw have published a list of the more than 350 frog species that live on the small African island.

 

The diversity of frogs can also be seen in reproduction. "Some undergo live births, others lay eggs. Some frogs even swallow their eggs and hatch them out through their stomach," explains Vences.

 

One species places tadpoles individually on water-filled leaves and feeds them with unfertilized eggs. In order to mate, frogs identify each other by the sound of their croaking as well as by their color.

 

"Despite all of this, frogs are actually pretty stupid. All of these incredible practices are controlled by instinct," says Vences. "Because amphibians have survived for so long, they are an important model group for evolutionary research." 

 

Read the original article in German