Climate Change Will Cause the African Clawed Frog to Spread in Europe



African clawed frog (Xenopus laevis) from Oeiras, Portugal. (Photo: M. Flecks)
Climate Change Will Cause the African Clawed Frog to Spread in Europe
post by
Reinout Verbeke

The African clawed frog Xenopus Laevis will soon find itself more at ease in Europe due to climate change, according to an international study that included biologists of our Institute. The frog is an invasive species and a potential carrier of diseases that have caused global declines in amphibian populations.

The African clawed frog, that owes its name to the claws on its hind foot, is native to South African wetlands, ponds and lakes. However, the frog has gone around the world as a model organism for scientific research. Geneticists have studied the development of its eggs and embryos, in order to identify the function of genes by knocking them out. In the 1940s and 1950s, this frog was even widely used as a pregnancy test (the urine of a pregnant human woman causes changes to the ovaries of a female frog).

The popular frog has been introduced in the wild, sometimes on purpose sometimes by accident, and has settled on four different continents, including Europe. There are some thriving Xenopus laevis populations in France, Portugal and Sicily. According to DNA analysis by researchers of the our Institute, the frog appears to derive from two different areas in South Africa. This means that the frog was introduced in Europe several times. In Portugal Xenopus frogs may have been accidentally released in 1979 when a research institute in Oeiras (close to Lisbon) was flooded. In 1996 frogs were probably released into the wild after a breeding facility in Bouillé-Saint-Paul (in the west of France) shut down. Luckily, the frog has not yet been observed in the wild in Belgium.

Invasive Species in Warmer Europe

Xenopus Laevis will eat almost anything, including insects, shrimps, snails, bait as well as other frogs. The frog has been known to show up in dense populations and often overthrows indigenous fauna. The invasive frog species is also a potential carrier of the skin fungus Batrachochytrium dendrobatidis and the Rana virus, that have already seriously damaged other amphibian populations.

Biologists of our institute participated in a study recently published in the journal PLoS ONE, in which they predict how the African clawed frog would spread around the globe. This was done by using algorithms that take into account various scenarios of climate change suggested by the Intergovernmental Panel on Climate Change (IPCC). The study concludes that the worldwide spreading of the African clawed frog will be contained, except in Europe. Here the climatic conditions of tomorrow will expand the habitat of the frog, especially in Portugal, Eastern Spain, the south of France and Italy.

Tracing the original habitat of invasive species and making predictions regarding their future dispersion makes it a lot easier to take the necessary precautions against the invasive species in Europe and elsewhere.


This research by the European consortium INVAXEN (Invasive biology of Xenopus laevis) was, amongst others, funded by Belspo.

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