I'm a drag-queen and I win. ;)

LUO CHUN YIN — Fri, 21 Mar 2008 08:04:00 GMT

Ok, so you've heard of marine animals such as the octopus and even cuttlefish being able to change colour, but I bet you didn't know that for a certain species of cuttlefish, this ability of theirs is so developed that their appearance change can fool their mates as well?

Anyone recognise this strange-looking big fella? I thought it looked quite gentle here in this video actually. Haha. Ok anyway, introducing the Australian Giant Cuttlefish! ( Sepia apama).

SO, what is so fascinating about this fella? Get ready to be surprised! ;)

Basically, some of the smaller-sized males of these big creatures can change their appearance so rapidly that they not only fool their competing male counterparts into thinking that they are female during intense mating competition, hence allowing these mimickers to get closer to the females, but the females themselves, for some reason, actually allow these mimickers to fertilise their eggs! Sneaky little biggies aren't they? Haha.

AND that is not all. According to this ScienceDaily article, ( you can read the full article here), “the cuttlefish can switch between a male and female appearance 10-15 times per minute.” It's no wonder that the bigger males and even the females themselves get confused!

Such behaviour is actually known as “sneak-mating”, which can take the forms of both overt sneak-mating as well as stealth sneak-mating. Of course, the cuttlefish employs all available tools in its arsenal, and that includes the well documented sexual mimicry as well. The latter often “leads to increased acceptance of mating with the female, and to immediate fertlisation, as demonstrated by DNA fingerprinting.” Now I know, the mimicries of animals have so many different purposes!

I couldn't exactly find a video of a smaller male switching its appearance so rapidly, but here is one video of a close-up of skin patterning changes, although by the same scientist who conducted the research mentioned above. There is one here on youtube of giant cuttlefish courtship too! You can clearly see the rapid colour and pattern changes in the male cuttlefish for this one. ;)

This post and all the relevant research that I did was actually inspired by a little chameleon I saw while in school yesterday. While the chameleon was,of course, not as flamboyant as the cuttlefish in changing colour, the distinct two half colours of a brownish-orange and green while it froze beside a tree root and stared right back at me made me wonder if it could change colour at will, or was it because of its surroundings that acted as some external stimuli. While I ended up not finding out the answer to that yet, I stumbled across a few magnificent videos of the flamboyant cuttlefish ( metasepia pfefferi) and became fascinated by cuttlefish instead. So I turned my focus to camouflage by the creatures of the deep instead, and voila! I think, the Australian Giant Cuttlefish certainly tops the list for fully maximising this colour changing ability. :)

References

a. Image used from http://achtel.com/Australian%20Giant%20Cuttlefish.jpg

b. It Pays To Be An Imposter. ScienceDaily. Retrieved March 21, 2008, from http://www.sciencedaily.com /releases/2005/01/050124005322.htm

c. Encyclopedia of Life, http://www.eol.org/taxa/16486539?category_id=194#

d. Youtube, Giant Cuttlefish of the Kelloe, http://www.youtube.com/watch?v=o0zFMb160EI

e. Youtube, Giant Cuttlefish Courtship, http://www.youtube.com/watch?v=MxiH3f-JsO4

Turning Green! Or grey? Or yellow?

CHUAN YELI — Fri, 21 Mar 2008 05:31:00 GMT

"Ahhhhhh! Oh my god!! That stupid chameleon gave me a fright!"

"Huh? Where, where?"

"It just ran past us! It's on the tree trunk now!"

"Huh? I can't see it!"

Have you ever had such an experience before? Personally, I had, many times. As we know, chameleons are well-known for their ability to display different colours within a short time. I always thought that they are really smart to be able to adopt this kind of colour-changing mechanism to blend into their surroundings so as to ward off possible predators, until I started surfing the internet for information about the reptile.

(image from http://news.softpedia.com/news/Why-Do-Chameleons-Change-Color-47360.shtml)

The chameleon is able to change colours via specialized cells, which are called chromatophores, under its outer skin layer. The top layers of the chromatophores consists of red and yellow pigments, while the lower layers consists of blue or white pigments. The messages sent to the chameleon's brain will inform it to alterits pigment cells to suit the current situation. It has a chemical called melanin as well, which primarily darkens it when released.

So, when do chameleons send messages to change their colour pigmentation?
Some researchers still believe that camouflage is one of the main reasons, which is similar in the cases of other animals such as the Golden Tortoise Beetle and the Flounder. However, other studies illustrate, contrary to common beliefs, that it is not true and quite the opposite in the case of the chameleon!

"Because these signals are quick--chameleons can change color in a matter of milliseconds--the animal can afford to make it obvious, as the risk that a predator will notice is limited.This finding means that the evolution of color change serves to make chameleons more noticeable, the complete opposite of the camouflage hypothesis."

- http://www.sciencedaily.com/releases/2008/01/080129125524.htm

Rather, it does so as a kind of communication as well as a form of response to changes in temperature. Although different species of chameleon can change into different colours or differ in the variation of colour change, the basic functions of this useful mechanism is quite consistent. The common situations when a chameleon displays colour changes are:

1) Temperature changes
For example, when it is cold, the chameleon might make itself darker, as darker colours trap more heat.

2) Light conditions
For example, when the chameleon is out in the sun for long, it might enlarge its yellow pigments so as to reflect the bright light away.

3) Mood changes/ Communication
    When two males want to compete with each other, this happens:

"If a male is challenged by another male they both begin by showing their brightest colours - until one figures out the other is going to win and changes to a submissive, dark, 'don't beat me up colour,"

    - Dr Stuart-Fox

Also, when a male chameleon is interested in attracting a female one, it will display striking and bright colours. This kind of courtship technique displays how sexual selection of the chameleon works- the more flashy and colourful, the more attractive a male chameleon is!

Since the main communication tool of the chameleon is through visual cues, colour changes play a most significant role in conveying various messages to other chameleons, such as the desire to mate as mentioned above.

From the video:

Please view this link because I don't know how to embed the video here!

http://www.youtube.com/watch?v=cNPDvsWISx0

I was very amazed at how colourful the male chameleon can become to get to hook up with the female one!

All the information I managed to derive from online sources, I am glad to say, have changed my opinion and knowledge about these small eyed and long-tongued reptiles! And they are so lucky-- they do not have to spend a bundle on new coats!

(image from http://en.wikipedia.org/wiki/Chameleon)

References:

http://library.thinkquest.org/C0115747/

http://www.wildwatch.com/living_library/other-2/chameleon

http://www.youtube.com/watch?v=cNPDvsWISx0

"Chameleon colour not to blend in" by Anna-Marie Lever
BBC News, 29 January 2008.

"Chameleons" by Sharon Katz Cooper. National Geographic, October 2002. Retrieved from http://magma.nationalgeographic.com/ngexplorer/0210/articles/mainarticle.html

PLoS Biology (2008, February 3). Conspicuous Social Signaling Drives Evolution Of Chameleon Color Change. ScienceDaily. Retrieved from http://www.sciencedaily.com/releases/2008/01/080129125524.htm

"Why do chameleons change colour? - It's about mood, temperature and light" By Stefan Anitei.
Retrieved from http://news.softpedia.com/news/Why-Do-Chameleons-Change-Color-47360.shtml

LSM1303 Animal Behaviour Student Blog : colour-changing

I'm a drag-queen and I win. ;)

Turning Green! Or grey? Or yellow?