Cephalopod Color and Skin discoveries

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
THANKS! When discussing night lighting for octopus tanks, @Neogonodactylus has mentioned that blue moon lights may actually be seen as brighter lighting than white tank lights. This paper supports those comments with the reaction of the skin chromatophores.
 

Stavros

GPO
Registered
Joined
Jun 26, 2008
Messages
168
Reaction score
38
Location
American University of Kuwait
Another article on squid & cuttlefish and a summary on both articles.

Edit #1: Corrected link.
Edit #2: A lot of journalists refer to this phenomenon as "seeing" which is not exactly the same thing. This is a non-visual type of light sensation which does not form an "image." Extraocular photoreception occurs, as the word implies, in sensory receptors found outside of any eye structures. It is found more or less in two thirds of animals (including humans) and it's used primarily in controlling/regulating physiological processes (circadian rhythm, orientation and navigation, biological clocks in general). As far as the chromatophore activation findings here, it could possibly be a mechanism that "automatically" adjusts reflected light intensity off the cephalopod skin, based on ambient light changes throughout the day.

@Starvos, the summary link is a title and not a link, I think this is the correct link but please change if I have the wrong article: http://jeb.biologists.org/content/218/10/1462.full
 
Last edited:

ekocak

Vampyroteuthis
Supporter
Joined
Dec 7, 2008
Messages
294
Reaction score
111
Location
Upstate NY, USA
Fascinating stuff. Could account for why they can mimic color and pattern so accurately without actually having eyes with color vision, yes?
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
@ekocak, I asked that same question years ago and at the time there was a hint (mentioned in the new article) that there may be something in the skin that facilitates the matching. At first, I could not think of a way this would let them "see" color but then started to wonder if further testing would show that different color chromatophores respond more to different wavelengths. If this could be shown, then it would show a new kind of color detection (not sure if we could call it vision). Exciting!
 
Last edited:

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Squid, octopus, cuttlefish: Ultimate shapeshifters
Science - MPR News Molly Bloom · Jun 24, 2015

Audio available in original posting (linked above)

When you think of camouflage in the animal world, you might immediately think of chameleons — but it's really cephalopods that should get your attention.

"This is an animal group that has probably the most beautiful and complicated and changeable skin on earth," said Roger Hanlon, senior scientist at at the Marine Biological Laboratory in Woods Hole, Massachusetts. "And we all know the chameleon, we love the chameleon, I think they are very cool. But they are dead boring in comparison."

Cephalopods include octopuses, squids and cuttlefish. They can change both their color and their shape.

Cephalopods have millions of tiny colored organs in their skin called chromatophores. They're like tiny sacks filled with color. On the skin's surface, they resemble tiny, colorful freckles that come in three shades: yellow, brown and red.

These chromatophores are attached to muscles that can pull on the organs to stretch them out or shrink them. If the cephalopod stretches out all the yellow ones, it can appear yellow. They can even mix the reds and yellows and browns to get a variety of shades and patterns.

But in order to blend into their surroundings underwater, they also need to be able to mimic blues and greens. For that, cephalopods use a different layer of the skin, which contains proteins that can reflect light.

Cephalopods can manipulate those proteins in order to reflect back the blues and greens and even purple coming from the light underwater.

So: One layer of skin has reflectors that can give off a blue or green or purple color. The layer above that can change to look red or yellow or brown. Combining all that, the cephalopods can create almost any color.

In addition to changing colors and patterns, cephalopods can also change the texture of their skin to help blend in.

In order to appear spiky or smooth — so they can mimic algae or coral, for instance — they use little lumps on their skin called papillae. Hanlon calls them "ultimate goose bumps."

The papillae can change shape in a way that's very similar to the way our tongues do. We can stick out our tongues and make them point, or we can flatten them out.

It's as though cephalopods are covered in lots of little super-shifty tongues that can almost instantly get really pointy or flat or round or bumpy.

To Hanlon, who has been studying cephalopods for 40 years, one of the most amazing things is how quickly they can change appearance to match their environment — it takes just 300 milliseconds. How they are able to do it so fast is still a mystery.

"So what is their secret? Is the octopus smarter than a human? Well, in this case it is," Hanlon said. "It makes you think about the visual perception. You are going to look around you as the octopus does, there is a tremendous amount of color and pattern information falling on your retina — but you don't have time to process all of that, because you'd require a brain the size of a Volkswagen. And to do it in 300 milliseconds — a third of a second — it is that shortcut that has fascinated us."
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Visualizing Biological Complexity in Cephalopod Skin: A Synergy of Art and Science Technologies
Elizabeth Kripke, Stephen Senft, Dmitry Mozzherin, Roger Hanlon 2015 (subscription)

Abstract

A cross-disciplinary team of artists and scientists is working to illuminate the detailed properties of dynamic coloration in squid, cuttlefish and octopus. They have synergistically fused the 3D animation software Blender with scientific bio-imaging techniques to better visualize the organization of cephalopod skin and its intricate web of nerve connections. This paper presents the practical benefits of the collaboration: how scientific detail has enriched artistic appreciation of these exquisite marine species and how artistic visualization has enriched scientific understanding of how cephalopods dynamically manipulate color.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Ethogram Analysis Reveals New Body Patterning Behavior of the Tropical Arrow Squid Doryteuthis plei off the São Paulo Coast
Felippe A. Postuma, Maria A. Gasalla 2015 (subscription)

Abstract
Squids can express several body patterns, aided by a variety of visual signals that are produced by chromatophore organs. However, for several squid species, body patterning behavior during reproductive activity is still not completely understood. For example, what are the specific patterning changes and other visual signals, how do they appear, and how long do they last? To test the hypothesis that distinct chromatic components appear at different durations on the skin of the tropical arrow squid Doryteuthis plei in the Southern Hemisphere, we identified and described its body patterning behavior. Specimen squids were obtained from off the South Brazil Bight, near the coast of the São Paulo shelf. Animals were maintained and monitored in circular tanks for 62 d over six observation periods, from 2011 through 2013. An ethogram was constructed showing 19 chromatic, 5 locomotor, and 12 postural components, or body patterns, associated with reproductive behavior. New chromatic components (i.e., those not yet reported in the North Atlantic D. plei species), particularly those linked to female sexual maturity, were observed. A postural component, the “J-Posture,” linked to defenses and alarm, also was noted. The average time spent for “light” components was 32 s. The corresponding “dark” components had an average duration of 28 s. Females displayed the chromatic components related to calm behavior longer than males. However, males appeared to be more dedicated to disputes over resources, and used rapid, miscellaneous visual signaling. In conclusion, new basic types of body patterns are described for D. plei. The repertoire of chromatic components reported in the ethogram is, to our knowledge, the first record for D. plei of the Southern Hemisphere.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Tactical Decisions for Changeable Cuttlefish Camouflage: Visual Cues for Choosing Masquerade Are Relevant from a Greater Distance than Visual Cues Used for Background Matching
Kendra C. Buresch,Kimberly M. Ulmer,Corinne Cramer,Sarah McAnulty,William Davison,Lydia M., Mäthger,
Roger T. Hanlon

Abstract
Cuttlefish use multiple camouflage tactics to evade their predators. Two common tactics are background matching (resembling the background to hinder detection) and masquerade (resembling an uninteresting or inanimate object to impede detection or recognition). We investigated how the distance and orientation of visual stimuli affected the choice of these two camouflage tactics. In the current experiments, cuttlefish were presented with three visual cues: 2D horizontal floor, 2D vertical wall, and 3D object. Each was placed at several distances: directly beneath (in a circle whose diameter was one body length (BL); at zero BL [(0BL); i.e., directly beside, but not beneath the cuttlefish]; at 1BL; and at 2BL. Cuttlefish continued to respond to 3D visual cues from a greater distance than to a horizontal or vertical stimulus. It appears that background matching is chosen when visual cues are relevant only in the immediate benthic surroundings. However, for masquerade, objects located multiple body lengths away remained relevant for choice of camouflage.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Tactile Sensing in the Octopus
Frank Grasso, Martin Wells 2015 (subscription)

Abstract
All animals must have a sense of touch, if only to avoid damage. The problem is to discover how much information about their environment the animals can derive from this sense. Octopus vulgaris has proved to be a useful tool for the investigation of how much a soft-bodied invertebrate animal can derive from contacts with its environment because it learns rapidly in the laboratory. The limits of its ability to discriminate can be deduced from the results of training experiments.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,544
Reaction score
1,762
Location
Gainesville, GA
Observed and modelled camouflage response of European cuttlefish (Sepia officinalis) to different substrate patch sizes during movement
Noam Josef, Igal Berenshtein, Meghan Rousseau,Gabriella Scata6, Graziano Fiorito, Nadav Shashar 2016 (Frontiers in Physiology PDF available)

Abstract
Camouflage is common throughout the phylogenetic tree and is largely used to minimize detection by predator or prey. Cephalopods, and in particular Sepia officinalis cuttlefish, are common models for camouflage studies. Predator avoidance behaviour is particularly important in this group of soft-bodied animals that lack significant physical defences. While previous studies have suggested that immobile cephalopods selectively camouflage to objects in their immediate surroundings, the camouflage characteristics of cuttlefish during movement are largely unknown. In a heterogenic environment, the visual background and substrate feature changes quickly as the animal swim across it, wherein substrate patch is a distinctive and high contrast patch of substrate in the animal’s trajectory. In the current study, we examine the effect of substrate patch size on cuttlefish camouflage, and specifically the minimal size of an object for eliciting intensity matching response while moving. Our results indicated that substrate patch size has a positive effect on animal’s reflectance change, and that the threshold patch size resulting in camouflage response falls between 10 and 19 cm (width). These observations suggest that the animal’s length (7.2-12.3 cm mantle length in our case) serves as a possible threshold filter below which objects are considered irrelevant for camouflage, reducing the frequency of reflectance changes - which may lead to detection. Accordingly, we have constructed a computational model capturing the main features of the observed camouflaging behaviour, provided for cephalopod camouflage during movement.
 

Forum statistics

Threads
19,755
Messages
203,711
Members
8,798
Latest member
dcoll01

Monty Awards

TONMOCON IV (2011): Terri
TONMOCON V (2013): Jean
TONMOCON VI (2015): Taollan
TONMOCON VII (2018): ekocak

About the Monty Awards
Top