article_snippet: Diver Chris Fallows captured this image. 
article_snippet: It was first observed by marine photographer Chris Fallows, who runs a dive boat operation from Cape Town in South Africa.
article_snippet: Mr Fallows, who runs Apex Expeditions, first noticed the behaviour in 2004 while on a dive off Cape Town.
article_snippet: A study on the behaviour is now published in the African Journal of Marine Science.
highlights_snippet: The unusual behaviour was spotted by divers off the coast of South Africa .
  