Alastair Tanner, a doctoral student at University of Bristol in England, wanted to better understand why those cephalopods lost their shells. So Mr. Tanner conducted a genetic analysis of 26 present day cephalopods, including the vampire squid, the golden cuttlefish and the southern blue-ringed octopus. “There’s a continual arms race between the prey and the predators,” said Mr. Tanner. “The shells are getting smaller, and the squids are getting faster.”The evolutionary pressures favored being nimble over being armored, and cephalopods started to lose their shells, according to Mr. Tanner. “It became a much more successful strategy to be a really high metabolism, very rapid moving animal,” Mr. Tanner said, “and they evolved into these really quite amazing things we see today.”

Source: New York Times March 06, 2017 18:33 UTC