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 strat
egy
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.
It's thought that
these catfish only target moving pigeons, as no attack on stationary
birds was ever witnessed. They also erect their barbels (the"whiskers"
that give them their name) when approaching pigeons, suggesting they
were using them to sense the vibrations caused by bathing birds.
Analyses of carbon and nitrogen levels of sample catfish (crayfish,
smaller fish and pigeons all have different levels, so the team could
see which prey a fish had been eating) demonstrated that catfish who ate
birds ate less fish.
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.
To see a video: http://bit.ly/11ZsGJq
The paper is available here: http://bit.ly/VHFy3v
http://
http://blogs.plos.org/
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 strat
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 strat
egy
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.
It's thought that these catfish only target moving pigeons, as no attack on stationary birds was ever witnessed. They also erect their barbels (the"whiskers" that give them their name) when approaching pigeons, suggesting they were using them to sense the vibrations caused by bathing birds. Analyses of carbon and nitrogen levels of sample catfish (crayfish, smaller fish and pigeons all have different levels, so the team could see which prey a fish had been eating) demonstrated that catfish who ate birds ate less fish.
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.
To see a video: http://bit.ly/11ZsGJq
The paper is available here: http://bit.ly/VHFy3v
http://
http://blogs.plos.org/
It's thought that these catfish only target moving pigeons, as no attack on stationary birds was ever witnessed. They also erect their barbels (the"whiskers" that give them their name) when approaching pigeons, suggesting they were using them to sense the vibrations caused by bathing birds. Analyses of carbon and nitrogen levels of sample catfish (crayfish, smaller fish and pigeons all have different levels, so the team could see which prey a fish had been eating) demonstrated that catfish who ate birds ate less fish.
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.
To see a video: http://bit.ly/11ZsGJq
The paper is available here: http://bit.ly/VHFy3v
http://
http://blogs.plos.org/
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