A squids intelligent mimicry technique

By Colin Ricketts - 28 Aug 2013 19:35:57 GMT
A squids intelligent mimicry technique

(a) Grimalditeuthis bonplandi when first observed by the ROV at approximately 1000 m. The tentacle club is deployed approximately four mantle lengths anterior to the brachial crown. The chromatophores are expanded to give a mottled coloration, the tail is spread flat and the fourth arm supports the proximal base of the tentacle stalk. (b) Close-up of tentacle club; the trabecular protective membranes (tr) of the club manus, indicated by white arrows, can flap to propel the club; Grimaldoteuthis Image; Credit: © MBARI

Remotely operated vehicles and submersibles enabled the observations of this unique animal in the Gulf of Mexico and off Monterey. Remaining horizontal most of the time, the fins maintained its position, although the heart shaped tail fin seemed simply to be the "rudder," with sensitive filaments attached. The ten arms were normally spread almost laterally.

In this deep-sea (well, meso and bathypelagic!) world of the Grimalditeuthis, tentacles are unnecessary to grip or grab. This is a unique animal, it seems. Instead of the normal grabbing procedure, the squid flaps the arms' tiny club to mimic a prey organism. It's possible the movement also stimulates bioluminescent organisms locally, in order to attract animals to the area, but the club's low frequency vibrations would also be picked up by several prey species.

Crustacea such as sergestid shrimps and octopods are certainly attracted and are regularly eaten, going by the gut contents. Instead of examining only dead specimens, modern tech. has enabled ROV and manned submersible observations of the squid here for the first time. The researchers spent several years examining their 7 live specimens as well as the preserved material available. It seems that instead of being an obvious mimic, the actions of the club attract this species' prey. Other species have been known to operate angling techniques in the sand or operate some kind of hypnotic "lure."

JT. Hoving and his five colleagues have published First in situ observations of the deep-sea squid Grimalditeuthis bonplandi reveal unique use of tentacles in the Proceedings of the Royal Society B: Biological Sciences.