French Catfish evolving
European catfish in Southwestern France have learnt how to catch birds by temporarily beaching themselves, a behaviour not seen in their native habitat.
These catfish live in the River Tarn (in the city of Albi) which contains a small gravel island. Pigeons come here to clean themselves, but unfortunately for them the catfish population has adapted to this food source. They have developed a strategy of lunging out of the water, grabbing a pigeon and wiggling back into the river. This behaviour is reminiscent of the way bottlenose dolphins and killer whales sometimes hunt, so much so that the researchers (University of Toulouse, France) refer to these catfish as “freshwater killer whales” in the title of their paper.
What’s especially interesting about this behaviour is that it’s not been seen in the catfish’s native habitat. The European catfish was introduced to Tarn in 1983, and seems to have successfully adapted their behaviour to fit their new environment. It’s not known what triggered this new strategy – have the catfish eaten the majority of the local fish? If not, why go to this effort? Though it currently stands as an example of unusual behaviour, this result could provide new knowledge of how new behaviour arises in a foreign ecosystem.
Photo credit: Cucherousset et al, 2012.
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The paper is available here: