So much for belief that they ‘lack intelligence’
Watch the video below closely and you’ll see an orange-dotted tuskfish digging out a clam and then carrying it to a suitable rock. She then throws the clam against the rock to break it open.
Not long ago, it was generally believed that humans were the only animals that use tools, and that this was one of the chief proofs of human exceptionalism compared to “the animals.”
That belief has long been shattered as we’ve seen chimpanzees using tools to pry ants from their nests; dolphins using sponges to protect their noses as they scour the ocean bottom for food – and, most recently, using shells to catch fish; and crows and other birds using sticks to collect ants.
But chimps, dolphins and corvids are known to be among the most intelligent of animals. So it’s a welcome surprise to see fish – often considered to be the least brainy of animals (many scientists still claim they can’t even feel pain) using tools in the same way as so many other animals.
The moment was shot off the Pacific island of Palau in 2009 by Giacomo Bernardi, an evolutionary biologist at the University of California, Santa Cruz. In the journal Coral Reefs, he writes:
…an individual C. anchorago was observed cracking bivalves using a rock as an anvil. After two such events, we started filming the behavior, which was repeated a third time (see Electronic Supplementary Material). Each event lasted less than 5 min, for a total observation time of approximately 20 min. The fish first dug out the bivalve by fanning sand with its pectoral fin and then took the mollusk to a rock, or coral head, where it was crushed in a similar way to what has been described for C. schoenleinii.
“The animal excavates sand to get the shell out,” Bernardi explained, “then swims for a long time to find an appropriate area where it can crack the shell. It requires a lot of forward thinking, because there are a number of steps involved. For a fish, it’s a pretty big deal.”