French catfish have picked up a new talent, as reported by Discover
As adaptive behaviors go, this one is very impressive, since the catfish are effectively stranding themselves on land, albeit briefly, to go pigeon hunting.
The video shows a learned behavior of a group of catfish in the River Tarn, in Southwestern France. The fish who exhibit the behavior of going pigeon hunting (or pigeon fishing) appear to be among the smaller, and younger of the European Catfish
species which was introduced to the area in 1983.
One researcher from Paul Sabatier University,Julien Cucherousset, heard of the phenomenon from local fisherman and investigated. In a series of observations, Cucherousset found that in 28% of the 54 attacks he observed, the catfish were successful.
Cucherousset collected some samples of the fish, plus samples of the catfishes primary food sources, crayfish, small fish and also the pigeons. Since each of the food sources are comprised of varying levels of both carbon and nitrogen, it was possible to determine which catfish were eating a traditional diet, and those who were more prone to dining on pigeons. Those eating pigeons tended to eat less fish.
Chucherousset observed that the catfish would raise their whiskers (barbels) upright to use them to sense when a pigeon was in the water, and moving about. It is suggested that it's the movement of the pigeons which prompts the attack and stranding, after which the fish wriggles back into the water with its squab supper.
A great many questions remain as to why the catfish have adopted this behavior, or even if the behavior is a positive adaptation to a stressed environment with fewer typical food sources for the catfish.
The Tarn catfish aren't the only fish which exhibit this behavior though, others such as a group of Killer Whales
off the coast of Argentina have adopted the same behavior to capture sea lions. Bottlenose dolphins
in South Carolina have also learned how to increase their food gathering techniques.
In all due deference to the old phrase, in this case: A bird in the mouth is worth two on the beach.