Octopi, squids, nautiloids. The cephalopods are just about the weirdest group of animals you’ll find. They have tentacles and beady eyes. Their evolution rivals that of humans. Given time and the right conditions, they might even develop sapience – ability to “penetrate deeply into ideas.” And they are armed.
The Glaucus site in the UK lists their characteristics thusly:
1) They are the most advanced of all the invertebrates.
2) They move by jet propulsion, squirting water from a funnel.
3) They are the most intelligent of the invertebrates, with a capacity for learning
4) Most of them are able to eject ink to confuse predators.
5) Most of them have a remarkable ability to change colour.
6) They have arms with suckers which they use to capture prey. (Octopuses have eight arms, squids have ten).
7) They have a hard beak to tackle prey with hard shells like crabs.
8) (Do we really need emoticons inserted automatically for us?) Their heyday was 100 million years ago in Cretaceous times when Ammonites were plentiful in the oceans of Earth.
9) Although they are molluscs, most of them have evolved to have only a diminished internal shell (the cuttlebone of the cuttlefish), or have lost their shell completely (octopus).
10) The Giant Squid, Architeuthis, is the largest invertebrate known, and stretched out with its tentacles included, it has attained 18 metres in length. Even larger specimens may await to be discovered in the deepest oceans.
Did you notice item #6 up there has the answer to the perennial question: what’s the difference between a squid and an octopus?
The cephalopods are a strange group all around, but some of its species seem to be the very definition of weird. For instance:
From Wikipedia: “These species exhibit an extreme degree of sexual dimorphism [difference between the male and female]. Females may grow to over 2 metres in length whereas the tiny males are at most a few centimeters long. The males have a specially modified third right arm which stores sperm, known as a hectocotylus. During mating, this arm detaches itself and crawls into the mantle of the female to fertilize her eggs. The male dies shortly after mating. The females carry over 100,000 tiny eggs that are attached to a sausage-shaped calcareous secretion held at the base of the dorsal arms and carried by the female until hatching.”
From Wikipedia: “Only the distal half (farthest from the body) of the arms have suckers. Its limpid, globular eyes, which appear red or blue, depending on lighting, are proportionately the largest in the animal kingdom at 2.5 cm (1 inch) in diameter.The animal’s dark color, cloak-like webbing, and red eyes are what gave the Vampire Squid its name.
Unlike their relatives living in more hospitable climes, deep-sea cephalopods cannot afford to expend energy in protracted flight. Given their low metabolic rate and the low density of prey at such depths, Vampire Squid must use innovative predator avoidance tactics to conserve energy. Their … bioluminescent “fireworks” are combined with the writhing of glowing arms, erratic movements and escape trajectories, making it difficult for a predator to home in.
In a threat response called “pumpkin” or “pineapple posture”, the Vampire Squid inverts its caped arms back over the body, presenting an ostensibly larger form covered in fearsome-looking though harmless spines (called cirri). The underside of the cape is heavily pigmented, masking most of the body’s photophores. The glowing arm tips are clustered together far above the animal’s head, diverting attack away from critical areas. If a predator were to bite off an arm tip, the Vampire Squid can regenerate it.”
That’s a picture of the vampire up there in today’s image.
Not much info on this group. Their claim to fame is their really long tentacles. Watch a YouTube video.
Japetella heathi Octupus
This small octopus can go transparent instantly. Nice trick.
Extra Cephalopod fun
Here’s a video of a cute baby octopus being annoyed by a human. Not sure who’s playing the organ down there, but it really adds to the ambiance, doesn’t it?
And finally we come to the Pacific Northwest tree octupus. It’s a hoax.
Hey, thanks for reading 31 Days of Weird Science. If you’ve got any leads on weird science, let me know about it. I’ll check ‘em out.
Sue Lange’s latest ebook, Tritcheon Hash, is full of lapses of logic and weird science. “It’s a wild, good read.” Get your copy right here at good ol’ BVC.
This essay was first posted on December 14, 2011 at the Singularity Watch blog.