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Camouflage is not a new concept in the animal kingdom. From grasshoppers blending in with leaves to owls mimicking tree barks, many animals, birds, and insects, depend on their ability to hide in plain sight for survival. But if there were an Oscar for the species with the best disguise, it would surely go to the dusky dottyback. The crafty predator fish can change its color to mimic that of its prey's parents, allowing it to feast on their juveniles, without raising suspicion.
The discovery that was published in Current Biology on March 19 was made by a team or researchers led by Dr. William Feeney from University of Cambridge's Zoology Department.
Though the color of the dusky dottyback can range from purple to gray, for their study, the scientists focused on the yellow and brown species that reside off Lizard Island in Australia's Great Barrier Reef.
Their curiosity stemmed from the continued hunting success rate of the predatory fish that sometimes swallows as many as twenty juvenile specimens of its favorite prey - the brown and yellow damselfish. There had been some suggestions that it was due to the dottyback's ability to change color, but the fact had never been verified
The researchers began by creating simulated reefs that contained both coral and coral rubble, and stocking them with yellow or brown damselfish. They then introduced the yellow and brown dottyback to the reef.
To their surprise, the crafty fish changed color if they found themselves amid damselfish of a different color. That means that if the dottybacks were in their 'brown' disguise and noticed yellow damselfish, they turned yellow and vice versa. According to the scientists who observed this crafty fish in action for a few months, blending in with the damselfish allowed them to prey on the young ones with greater ease and increased their hunting success almost threefold.
This extraordinary skill to change to different colors also means that their prey never catches on to the trick, ensuring the dottyback continued success.
What's even more interesting is that mimicking the damselfish that has adapted to match the color of its environment also helps protect the dottyback from its predators.
The researchers tested this by subjecting its biggest predator, the coral fish, to images of different colored dottyback against various habitats. Sure enough, the coral fish had the most success when the dottyback stood out against the background.
The researchers say that the color morph, which takes about two to three weeks, is caused by the dottyback's ability to alter the ratio of its yellow and black chromatophores, the pigment-containing cells that reflect light. While the number of cells remains constant, the fish can bring more of the black cells to the surface when going for the brown disguise and vice versa.
According to Feeney, "This is the first time that an animal has been found to be able to morph between different guises to deceive different species. He calls the dottyback, a real-life "Wolf in sheep's clothing", except in this case, the wolf never gets detected!