A BIZARRE tropical fish bags its dinner with a neat trick that should be the envy of cricketers and baseball players.
The archer fish is famous for being able to knock unsuspecting insects from overhanging twigs with a well-aimed spit of water. But dislodging the morsel isn鈥檛 enough. The mangrove swamps of South East Asia and Australia where archer fish live are teeming with competitors that would be only too glad of a free lunch. So the marksman has to get to its prey as quickly as possible.
Stefan Schuster and colleagues at the University of Freiburg in Germany wondered if the fish were able to predict where their dinner would land, rather than simply chasing it as it falls towards the water. So they set up tanks containing six fish with a tasty insect suspended above them to find out.
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They found that the fish started sprinting towards their victims within 100 milliseconds of a hit, making their reaction time twice as fast as the average human鈥檚. More impressively, they headed straight for the point where the insect eventually hit the water. Even when the researchers teased the fish by offering targets that were tied to a string to stop them from hitting the water, the fish still swam straight to where their prey would have landed (The Journal of Experimental Biology, vol 205, p 3321).
The fish extract all the information they need to predict the trajectory in the first 100 milliseconds of the prey鈥檚 flight. 鈥淭hey are not bothered by visual input once they are going,鈥� says Schuster, and this saves the archer fish a lot of time.
Humans faced with a similar problem solve it differently. Fielders in games such as baseball and cricket keep their eye on the ball, running in a curved path to keep track of where it will land (New 杏吧原创, 6 May 1995, p 18). That helps them to catch the ball, but it means running further, which takes longer. 鈥淭he archer fish would be the better outfielder,鈥� says Schuster.