PZ Myers. 2005 Jan 27. Squid attack!. <http://pharyngula.org/index/weblog/squid_attack/>. Accessed 2008 Dec 01.

Posted on M00o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr on Thursday, January 27, 2005

Squid attack!

If anyone is interested in writing a Lovecraftian horror novel and getting all the details just right, I recommend this paper by Kier and Leeuwen. They used a high-speed camera to capture exactly how a squid, Loligo pealei, strikes and seizes its prey. Isn't it beautiful?

In the first frame, you can see the animal poised with its arms and tentacles pointed like an explode at the target, a shrimp. Then, as the squid slides forward, the two tentacles race forward with impressive speed (these frames are 10msec apart; the whole sequence occurs in a bit more than a tenth of a second), and the eight surrounding arms peel back and form a lovely writhing flower of suction cups and waving hydrostatic grasping organs. Oh, this is such a splendidly baroque little carnivore.

squid strike
squid strike
squid strike
squid strike
Photographs of selected frames from a high-speed ciné sequence of the capture of prey (a penaeid shrimp) with the tentacles by Loligo pealei. The elapsed time (ms) from the start of the sequence is indicated in the upper left-hand corner of each frame and corresponds to the time indicated by the abscissa of the plots in Fig. 2. The grid spacing in the background is 0.02m.

Kier W, Leeuwen J (1997) A kinematic analysis of tentacle extension in the squid Loligo pealei. J. Exp. Biol. 200:41-53.

Posted by PZ Myers on 01/27 at 11:51 AM
Science • Organisms • 1 Trackbacks • Other weblogs • Permalink
  1. Beautiful.
    #: Posted by  on  01/27  at  02:00 PM
  2. Interesting that the net motion of the beasty is in the forward direction throughout the grab; I would expect the tenticle thrust forward to drive him back a bit, if anything. And my understanding (almost certainly flawed) is that they don't move very efficiently in that direction.

    He (?) is a far more elegant eater than many of my old roomates, regardless.
    #: Posted by Evan Murdock  on  01/27  at  02:57 PM
  3. Considering the time this takes, it certainly is amazing.
    #: Posted by mattH  on  01/27  at  03:24 PM
  4. I'm going to suspend my water creature hate for a moment: that was beautiful. Got good gams.
    #: Posted by Lauren  on  01/27  at  04:20 PM
  5. I suspect the peeling off and backward curl of the arms isn't just for show -- any backwards push caused by thrusting the two tentacles forward could be more than offset by throwing eight arms back.
    #: Posted by PZ Myers  on  01/27  at  04:45 PM
  6. Those photos make we wonder if this little guy's larger Architeuthis cousins can generate the same velocity when they fire off those tentacle clubs. Good thing they don't like warm surface water!
    #: Posted by Timageous  on  01/27  at  05:36 PM
  7. Architeuthis seems to have been a rather pasive hunter, dangling its extremely long tentacle clubs below into schools of fish and waiting for something to swim between.
    #: Posted by  on  01/27  at  06:12 PM
  8. And, by the way, "baroque" is an excellent descriptor.
    #: Posted by Lauren  on  01/27  at  07:42 PM
  9. This paper can be viewed at CephBase:

    http://www.cephbase.utmb.edu/refdb/pdf/7190.pdf
    #: Posted by  on  01/27  at  08:18 PM
  10. Architeuthis seems to have been a rather pasive hunter, dangling its extremely long tentacle clubs below into schools of fish and waiting for something to swim between.

    Does its passive hunting account for the differences in sucker appendage? For instance, I believe that Architeuthis dux has circular, saw-like appendages, while this little guy has hook-shaped appendages on its tentacle clubs. I suppose the saw-like appendages saw into fish like hagfish mouths?
    #: Posted by Timageous  on  01/28  at  01:19 PM
  11. Looks like that little shrimp is...
    #: Posted by  on  01/28  at  01:26 PM
  12. Forgive my ignorance of squid natural history, but what is it that differentiates "arms" from "tentacles"?
    #: Posted by  on  01/28  at  06:42 PM
  13. Every squid has arms, but only the boys have tentacles ;)

    In reality, tentacles are longer and only have suckers at the tips. A squid has ten appendages total (8 arms, two tentacles).
    see http://en.wikipedia.org/wiki/Tentacle for an illustration of a cuttlefish, which is analogous in structure.
    #: Posted by  on  01/28  at  07:10 PM
  14. "Tentacles", in the case of squid, are the 2 thin and highly extensible raptorial appendages with 'clubs' at the distal end. The clubs are equipped with a generally nasty array of suckers and/or hooks used to obtain a firm grip on prey. The tentacle stalks are usually 'naked', having no suckers or hooks. "Arms" are the 8 other appendages which bear suckers and sometimes also hooks.
    #: Posted by  on  01/28  at  07:11 PM
  15. The cephalopod pages at the Tree of Life are quite good:

    http://tolweb.org/tree?group=Cephalopoda
    #: Posted by  on  01/28  at  07:13 PM
  16. The tentacle stalks of Architeuthis have suckers, though no where as dense as on the club, as well as knobs which fit into depressions on the other stalk. This allows the two stalks to remain tightly apressed along their length leaving the club ends of the tentacles free like a pair of salad tongs.
    #: Posted by  on  01/28  at  08:21 PM
  17. I think that chranchiids (mostly smallish transparent squids possessing a buoyancy chamber filled with ammonium chloride) also tend to have suckers on their tentacle stalks, though generally not on the more proximal 1/3 or so. Is this more characteristic of 'buoyant' squids, I wonder?
    #: Posted by  on  01/28  at  09:36 PM
  18. So, technically speaking, an octopus doesn't have tentacles, only arms? Or does this terminology only apply to squids?
    #: Posted by  on  01/29  at  09:07 PM
  19. That's right: an octopus has 8 arms and no tentacles.

    There's a good page on basic cephalopod anatomy on TONMO.
    #: Posted by PZ Myers  on  01/29  at  09:22 PM
  20. Perhaps Ken McLeod should've read that page before he wrote his "Squids in Spaaaace!" trilogy, in which he describes them as octopods, when, as any fule kno, it's decapods.
    #: Posted by Republic of Palau  on  01/31  at  06:31 AM
  21. Although you could almost forgive a person for referring to a squid such as Taningia danae, or any of the other octopoteuthids, as an 'octopod'. These guys have little or nothing in the way of tentacles past the paralarval stage, and lack them as adults. You'd have to pretty silly, though, to actually confuse them with the Octopoda. Decapod suckers come equipped with horny rings, for instance, while octopod suckers don't.
    #: Posted by  on  01/31  at  09:39 AM