Tusk fish uses rock to open cockle shell

Authors: Max Mason
Newspaper: The Sydney Morning Herald
Year: 14 September, 2011

Man’s ability to use tools was once thought to distinguish him from other animals. Since then, other animals have been added to the list. Now fish can be added as well. A Tusk fish was observed in the Great Barrier Reef using a rock to open cockle shells. Other fish have been seen in captivity also using tools.

"Tool use, once thought to be exclusive to animals with highly developed brains, has been recorded for the first time by a fish in the wild."

"Tusk fish have been photographed appearing to be smashing open cockle shells that were between two and eight millimetres thick."

"The pictures were taken by Scott Gardner during a dive at Egg Rock in the Keppel Islands, a protected area of the Great Barrier Reef, in June."

"The fish grasps the bivalve in its mouth and swivels its body back and forth, landing alternate blows on the sharp part of the rocks. After several blows, the bivalve cracks open and the fish eats the meat inside."
"Alison Jones, from the Centre for Environmental Management at Central Queensland University, said: ’Even more astounding, and something that the photos do not do justice to, is that the fish is quite large [in the order of 60-80 centimetres] and that the cockle [shell] is also very big and quite thick and dense.’"

"’The nature of shells so thick is to be quite difficult to smash. The bivalve has a muscle that works in a similar fashion to a croc’s mouth: one way is easy and the other takes an extraordinary amount of effort,’ Dr Jones said."

"Dr Brown said there had been a few recorded cases of tool use by fish in captivity, making this a landmark event for behavioural ecology."
Fish Pain