Sharks’ Memories Better than You Thought

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  • Author: D.O. Gordon
  • Press: Shark Magazine
  • Date: Monday, 09 March 2015

The grey bamboo shark lives in the Indo-West Pacific Ocean. Dr. Vera Schluessel in Bonn Germany has been researching its intelligence and has made some very interesting discoveries.

The shark, Chiloscyllium griseum, grows to a length of approximately 2 feet. A carpet shark often has a pattern reminiscent of an ornate carpet and feeds along the bottom of the seabed. Dr. Schluessel’s PhD student tested young sharks to gauge how long they could remember skills taught in cognition experiments.

The first experiments worked with shapes. The sharks’ tank had images projected onto one of the walls. They were trained to identify the triangle by touching it with their nose, this resulted in a piece of food (reward) being provided. Half of the sharks were taught to identify a triangle, and half a square.

The next test used circles with points cut out to imply the shape of a triangle or square (similar to Pacman). The shape was not outlined fully, but could be perceived by the placement of the circles. The sharks were not fooled. They viewed the optical illusions and identified the shapes they had been trained to recognize. Not all animal species are able to view optical illusions. Cats, monkeys, owls, chicken, and goldfish are also similarly capable.

This ability to “fill in” the blanks to perceive the implied shapes likely improves their skills for escaping predators.

The next experiments included identifying empty shapes on a diagonally lined background and differentiating them from other figures. This was accomplished easily and quickly by the sharks.

This moved them on to the most difficult task. It was designed to have sharks identify the longest line in a series. They then progressed to the optical illusion portion of the test. You may have seen this graphic:

shark

CC by 3.0 by Fibonacci

The sharks had no trouble picking out the fact that the lines were the same length.

Nearly a year later, almost all of the sharks still remembered how to perform all of the skills they had been taught. Obviously, all sharks have different traits and different memory spans. Nothing was studied beyond a year as far as memory because the research turned towards the sharks’ brains and the area that controls memory. This is currently unknown. Researchers have yet to determine what area in the brain processes memories or stores the information.

Based on this new information, it is possible that other shark species have similar capabilities. Until further studies are conducted, we won’t know if all sharks have one year or more memories or if it is particular to a specific species.

It would be compelling information and possibly lifesaving in the long run. If we understand shark memory, we might be able to apply the information to understanding whether there the use of patterns would be helpful in deterring sharks from beach areas or other dangerous waters.

Hopefully, more scientists are studying how the shark brain works and will help us understand some of the sharks’ behaviors. 

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