SANTA CRUZ, Calif., Sept. 28 (UPI) -- A U.S. researcher says he has captured the first video showing the use of a tool by fish.
In a video taken by University of California, Santa Cruz, biologist Giacomo Bernardi in Palau in 2009, an orange-dotted tuskfish digs a clam out of the sand, carries it over to a rock, and repeatedly drops or bangs the clam against the rock to crush it.
"What the movie shows is very interesting. The animal excavates sand to get the shell out, then swims for a long time to find an appropriate area where it can crack the shell," Bernardi said in a university release Wednesday. "It requires a lot of forward thinking, because there are a number of steps involved. For a fish, it's a pretty big deal."
The video evidence supports previous reports of tool use by fish, all involving a species of wrasse using a rock as an anvil to crush shellfish.
"Wrasses are very inquisitive animals," Bernardi said. "They are all carnivorous, and they are very sensitive to smell and vision."
Tool use was once considered an exclusively human trait but many other animals have been observed using tools, including various primates, several kinds of birds, dolphins and elephants.