Agressive Squid Questions

[OctopusV]

I have two questions about the two more agressive squids.

First, does the Humbolt Squid (D. gigas) lack tentacles? I've recently noticed that I've seen the eight arms on the thing, but never any tentacles.



Second, how does the swivel motion on the Colossal Squid's (M. hamiltoni) arm-mounted claws work? In last year's newscast about a Mesonychoteuthis carcass, I saw Steve (or Kat) stick a finger towards one of the claws, and push it in a circular direction so that it made it seem that the squid can swivel it's claws, I'd like to know how that's structured and how that swiveling works.

I've been racking my brain and searching the 'net, and haven't found a thing that helps answer these two questions.

 

[um...]

Re: Agressive Squid Questions

First, does the Humbolt Squid (D. gigas) lack tentacles? I've recently noticed that I've seen the eight arms on the thing, but never any tentacles.

A photo of D. gigas, showing tentacles. (second squid)

 

[um...]

Here's a bunch of videos, in some of which the tentacles can be seen.

OceanFootage.com is .

 

[Clem]

Hello OctopusV,

Great questions. I don't think it's yet been determined how M. hamiltoni utilizes the swivels the claws are set into. It's probably unlikely that it can control each swivel-claw independently, since it would really have no cause to do so. Perhaps it can "reset" the claws so that all the recurved claw-points are oriented in one direction, pointing towards the head, before the tentacles shoot out to grasp prey. Or, maybe the tentacular claws lack muscular contols, and are spun into the proper configuration by the movement of water shooting past the manus (the "hand" at the end of the tentacle)?



Clem

 

[Burstsovenergy24]

Cool thinks. 8)

You must have thought about that for a while eh, Clem?

 

[WhiteKiboko]

The hooks can all move independently. Whether they actually do is another question... having no recorded observations of them swiveling on a live animal, we don't even know if the animal actively rotates them (whether individually or at once), or whether they just turn all the way around 'so as' (Steve's gonna kill me for suggesting directional evolution) simply not to be pulled out when the prey thrashes. If they were stationary, I think there'd be a greater chance of losing them once the squid had grabbed a presumably struggling Patagonian Toothfish.

that was from another thread last spring after i asked if the squid had direct control over the rotation....