Diver Scott Gardner has collected the first ever evidence of tool use in fish with these images: this blackspot tuskfish (Choerodon schoenleinii) held a clam in its mouth and repeatedly bashed it against a rock until it cracked, enabling the fish to consume the soft bivalve within. Fragments of shell were scattered around the rock and found across Australia’s Great Barrier Reef where the fish was observed, suggesting this is not an isolated incident. The fish join various other species that have displayed use of tools, including capuchin monkeys and New Caledonian crows amongst others. The definition of “tool use” is controversial, and debates are on-going as to whether this behaviour truly constitutes tool use. A number of scientists believe that the tool, in this case the rock, must be held or manipulated by the animal in order to be classified as true tool use. But, with only their mouths to manipulate tools with, this is about as close as a fish could get. Some label the behaviour “proto-tool use”, which also encompasses behaviour such as gulls dropping shellfish onto hard surfaces to crack them.
Ref: Kessier (2011) Diver Snaps First Photo of Fish Using Tools. Science online news [link]
WHAAAAAAAAAAAAAAAAAAAAAAAAAT THIS IS AMAZING EVERYBODY DROP WHAT YOU’RE DOING AND BE AMAZED FISH CAN USE TOOLS*!!!
*= the more proper way to say this would be “one fish has been observed utilizing its environment to its advantage” but that takes too long and this is too cool for me to worry about wording.