The Giant Pacific octopus is the largest octopus. According to Oceana.org:
The largest individual on record weighed an impressive 600 pounds and measured 30 feet across in length.
That's a big octopus! I love them for their intelligence and versatility, but also cephalopods have some incredible physiological adaptations. Please allow me to rant away!
Cephalopods can change the color and texture of their skin! It all starts with the humble chromatophore. Chromatophores are cells found just below the skin that contain pigment and can reflect light. To contrast, mammals and birds have melanocytes. Amphibians, fish, reptiles (Chameleons), crustaceans and some insects (Dragonflies/damselflies) also use chromatophores to change their coloring.
Chromatophores contain a sack of pigment (black, brown, orange, red, or yellow) which has the ability to expand. If stretched out the color will be brighter, if retracted the color will appear duller. In this gif you can see them in action! Some cephalopods also have iridophores and leucophores. Iridophores have stacks of reflecting plates which create iridescent colors (blues, golds, greens, and silvers) which you can see in this photo of Loligo pealei. Leucophores mimic environmental colors, helping the squid/octopus/cuttlefish blend in with its surroundings.
What is extra awesome is chromatophores can be used to mesmerize or stun prey! In this video, a cuttlefish is doing just that to keep a crab busy before grabbing it.
There was a study in 2015 where scientists strapped cameras onto Humboldt squid to try to decode the communication. I didn't see anything super conclusive in the article, but I would assume they are working on it. It's a really great topic.
The octopuses [in the study] had three dedicated types of muscles that control their on-call skin protrusions, or papillae. One set are shaped in concentric circles to lift the skin vertically away from the body. Another set pulls this form together, to determine the shape—whether it will be a round bump or tall spike. And a third group seems to pull the raised section back toward the surface, spreading out its base.
Edit - I have received a few PMs from wonderful folks looking into ecology and biology as a career path. I'm always happy to answer any questions you have about that. I have a few helpful posts in /r/fillsyourniche you can check out if you're curious about what I do now/have done/how I got where I am today.
claude_jeter on August 15th, 2018 at 15:48 UTC »
Banana for scale?
BigFoote18 on August 15th, 2018 at 17:43 UTC »
How many tickles make an octopus laugh
Ten tickles. Hahahhaha cause u know tentacles haha oh lord someone stop me.
FillsYourNiche on August 15th, 2018 at 18:21 UTC »
Ecologist swimming in. My favorite invertebrates!
The Giant Pacific octopus is the largest octopus. According to Oceana.org:
That's a big octopus! I love them for their intelligence and versatility, but also cephalopods have some incredible physiological adaptations. Please allow me to rant away!
Cephalopods can change the color and texture of their skin! It all starts with the humble chromatophore. Chromatophores are cells found just below the skin that contain pigment and can reflect light. To contrast, mammals and birds have melanocytes. Amphibians, fish, reptiles (Chameleons), crustaceans and some insects (Dragonflies/damselflies) also use chromatophores to change their coloring.
Chromatophores contain a sack of pigment (black, brown, orange, red, or yellow) which has the ability to expand. If stretched out the color will be brighter, if retracted the color will appear duller. In this gif you can see them in action! Some cephalopods also have iridophores and leucophores. Iridophores have stacks of reflecting plates which create iridescent colors (blues, golds, greens, and silvers) which you can see in this photo of Loligo pealei. Leucophores mimic environmental colors, helping the squid/octopus/cuttlefish blend in with its surroundings.
What is extra awesome is chromatophores can be used to mesmerize or stun prey! In this video, a cuttlefish is doing just that to keep a crab busy before grabbing it.
Aside from mesmerizing prey and camouflage cephalopod colors are also used to attract mates and warn potential predators or rivals that the organism should not be messed with. For example male Caribbean reef squid (Sepioteuthis sepioidea) turn red to attract females and white to repel other males. Interestingly they can actually split the coloration of their bodies down the middle to attract a female on one side and repel a male on the other. Another example, Humboldt (Dosidicus gigas) squid will flash red and white to warn predators. If you're into Humboldt squid, Science Friday has a great article I recommend reading, John Steinbeck And The Mystery Of The Humboldt Squid.
There was a study in 2015 where scientists strapped cameras onto Humboldt squid to try to decode the communication. I didn't see anything super conclusive in the article, but I would assume they are working on it. It's a really great topic.
Some cephalopods can change the texture of their skin by manipulating muscular hydrostats. Hydrostats can change shape by squeezing some segments to create extension others. Our tongues have muscular hydrostats which allow us to stretch it out. According to a paper published in 2014:
More on that in this Scientific American article.
Edit - I have received a few PMs from wonderful folks looking into ecology and biology as a career path. I'm always happy to answer any questions you have about that. I have a few helpful posts in /r/fillsyourniche you can check out if you're curious about what I do now/have done/how I got where I am today.