Photo/IllutrationThe mollusk Scintilla philippinensis does an impersonation of a crab (Provided by Hiroshi Miyake, an associate professor of aquatic animal ecology at Kitasato University)

  • Photo/Illustraion
  • Photo/Illustraion

It looks like your everyday mollusk, but that changes when danger looms.

First, the bivalve pretends to be a nudibranch sea slug. If the threat persists, it impersonates a crab and flees sideways just like the real thing.

Scintilla philippinensis is basically a master of disguise: the Zelig of ocean life.

Mimicry in the ocean is a well-known survival technique used by tiny creatures such as the mollusk.

But it is rare to find a species of bivalve that can pretend to be one creature and then switch disguise to another to suit the situation.

This particular mollusk that uses a two-phased survival tactic was discovered around Palawan Island in the Philippines by a Japanese team headed by Susumu Otsuka, a professor of marine biology at Hiroshima University.

The shelled bivalve usually hides behind rocks, but when in danger, such as being spotted by a fish, the tiny creature slips into stealth mode.

The 1.5-centimeter-long bivalve appears to resemble a sea slug and a crab because some types of sea slugs and crabs have poison in their bodies.

“Since mimicry is a method of deflecting attention away from predators for a moment, the creature doesn’t have to look exactly like what it is pretending to be,” said Otsuka.

“Scintilla philippinensis probably gained such mimicry in the process of its evolution,” he said.

The study results were published in January in the international journal of the Malacological Society of Japan.