Electric acne - a historically established name of unusual leafers who can affect victims by electrical discharges. Today they are related to the genus Electrophorus, in which there are three kinds of fish living in the reservoirs of South America. The most powerful blows cause Electrophorus Voltai: voltage can reach 860 volts. The blow disrupts the innervation of muscles and temporarily paralyzes the victim, allowing it to grab it without an accurate and complex aiming in muddy river water.
Sometimes whole shoals of these acne are hunting and discharged coordinated, reinforcing the deadly effect of the current and hitting the mass of small fish. Such amazing behavior recorded a team of zoologists led by David de Santana (David de Santana) from Smithson Museum of Natural History. They told about it in an article published in the magazine Ecology and Evolution.
A few years ago, during the expedition to the Amazon Pool, Brazilian scientists first noticed that in one of the tiny local lakes, electric acne gathered in the amount of more than a hundred - this was considered completely unusual for these loners. Surrounding the flock of petty fish, they narrowed the circle, knocking it up to the coordinated attacks by small groups, forcing it in small groups, forcing them to emerge a lot of victims and joining them.
The observation turned out to be extremely unusual if only because group hunting is a rarity for fish. According to de Santana, from thousands of species no more than nine demonstrate such behavior. Therefore, Brazilian scientists called for assistance to colleagues led by prominent specialists from the Smithson Museum and organized a new, more prepared expedition. This work confirmed the find made by them.
Most of the ELECTROPHORUS VOLTAI day remains sediments and dormant at the depths of muddy river water. However, at dusk, they are activated and harvested with large flocks, swimming wide circles until they surround a suitable flock of small fish, concentrating it and kicking out from depth to the surface. A similar tactics use humpback whales in the ocean, however, the eroxes then unfold their "electric strokes" attack. In groups of 2-10 individuals, they are coordinated in coordinated, paralyzing the mass of production, which everyone immediately attaches. Next, the process is repeated: when the electrical organs of the first group of acne are already discharged, there is a turn of the following.
In total, the researchers recorded 72 cases of such a group "hunting with electric strokes". The authors note that such behavior is still seen only at Electrophorus Voltai - and only in a small lake at the Amazon River Iriri. Therefore, it is not known how widely it is distributed, and if not, then why it appeared here.
Perhaps the problem in a lack of sufficiently large prey in this reservoir: electricity consumption for each individual small fish - too expensive pleasure for acne, so group hunting allows you to use resources more efficient. De Santana and his colleagues have already issued the necessary documents to collect several copies of these fish and transportation to Germany, where scientists plan to explore their group behavior in the laboratory.
Source: Naked Science