A new study of archer fish in Thailand has found an incredible level of accuracy and adaptability in the archer fish's ability to hit prey with water ejected from its mouth. Stefan Schuster and Peggy Gerullis from the University of Bayreuth in Germany and colleagues conducted the study. The research was reported in the Sept. 4, 2014, edition of the journal Current Biology.
The researchers show that the archer fish is the first known animal to use water as a tool. Using tools has previously been thought to necessitate large brain capacity like mammals. The study definitely shows that the archer fish has developed an extraordinary level of control over the distance it spews water at a prey target and the coordination of eye and body position necessary to achieve a near 100 percent level of accuracy in hitting prey targets. Videos of the archer fish in action can be seen here.
The scientists trained archer fish to hit targets that were eight to 24 inches above the fish. The average length of an archer fish is about three inches. The fish change the cross-section of their mouth opening in order to produce a precisely formed water drop that is regulated in size for the distance between the fish's mouth and the target. There are seven known species of archer fish and one can reach 16 inches in length.
The researchers liken the archer fish ability to hit a target to humans throwing rocks or spears at prey targets. The development of targeting in humans is thought to have forced human brains to increase in size. The archer fish ability cannot be attributed to brain size but the neuronal connections between mouth, eyes, and body positioning must be present.