I recently saw a documentary on Discovery Channel about the behavior of the octopus, Octopus Vulgaris, and decided to look for the video and share with everyone how amazing this “quick-change” artist is.
Actually, the octopus belongs to the class, cephalopod, which also includes cuttlefish, squid and nautiluses. Animals in this class are said to be able to change their body colours even faster than a chameleon.
Cephalopods exhibit different types of body patterns for different situations. As mentioned in the first video, it is an important way of communication, be it with fellow species, their prey or predators.
The different body patterns on the octopus are brought about by the dual action of thousands of chromatophores, which are small pigmented organs (subjectively classified into two or three colour classes per species: red, yellow/orange, and brown/black), and by light-reflecting cells. These chromatophores are attached to dozens of radial muscles that are innervated directly by the visual part of the brain, and by contracting and relaxing these muscles, the pigmented sac of a chromatophore increases or decreases in area and hence enables cephalods to produce an array of body-patterning components, such as bands, strips and spots.
From the Video:
0:08: Mating of cuttlefish. The male cuttlefish displays a “range of tones” to attract the female cuttlefish
0:35: “strange and rhythmic pulsing” by the cuttlefish – “the passing cloud”. Cuttlefish use this technique to mesmerize their prey and hence making them an easy target.
1:07: The blue ring octopus, Hapalochlaena lunulata and Hapalochlaena maculos, is highly venomous. One bite from the octopus is enough to kill. Hence, the octopus emphasizes this fact by using “vivid warning colours” – the blue rings.
1:33: My favourite part of the video. The way that the octopus protects itself from predators is very intriguing, especially the one shown in the video. The octopus first camouflages itself on the rock, so well that you do not notice it. When the predator comes too close for comfort, the octopus reveals itself and spreads out its tentacles to appear bigger than more intimidating. Then it darts away, leaving a trail of “inky smoke screen” that is foul-tasting.
2:05: Octopuses can not only change their body colour but also their body texture so as to completely blend into its surroundings. “It can blend with any background.”
2:57: One of the most threatening displays of bluff – “the owl face”. The octopus only reveals its face, to imitate a bigger animal, such as the stingray.
According to research and the video, octopuses have cognitive abilities. In the first experiment, the octopus is able to recognize the layout of the maze. In the second experiment, the octopus is able to recognize the shapes and remember that the food is behind the cross shape.
Master of Shape change
The last part of the video mentions a bit about the Indonesian Mimic Octopus, Thaumoctopus mimicus. This species of octopus is known to be the best imitator of other sea animals. The second video demonstrates the three types of sea animals that the mimic octopuses usually imitate.
0:53 – flounder. The flounder has toxic in its skin, hence predators would avoid it. The octopus imitates the flounder by drawing “all of its arms together into a leaf-shaped wedge as it undulates in the manner of a swimming flat fish”. (marinebio.org)
1:35 – lion fish. The lion fish’s fins tips have venom, hence predators learn to avoid them too. “The octopus hovers above the ocean floor with its arms spread wide, trailing from its body to take on the appearance of the lion fish’s poisonous fins.” (marinebio.org)
2:13 – sea snake. The sea snake uses its venom to imobilize its prey. The octopus changes colour, taking on the yellow and black bands of the toxic sea snake as it waves 2 arms in opposite directions in the motion of two sea snakes. (marinebio.org)
0:33: the amazing speed of colour change when the octopus is threatened.
“This animal is so intelligent that it is able to discern which dangerous sea creature to impersonate that will present the greatest threat to its current possible predator. For example, scientists observed that when the octopus was attacked by territorial damselfishes, it mimicked the banded sea snake, a known predator of damselfishes.”
“Dangers on the Reef…..Blue Ring Octopus“, by barrierreefaustralia.com. URL: http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm (accessed on 01 Apr 2010).
“Hawaiian Marine Life Profiles: Invertibrates – Octopus“, by Maui Ocean Centre. URL: http://www.mauioceancenter.com/index.php?id=11&ss=0&page=marine&content=marine_detail&cat=2&CRid=31&limitstart=0 (accessed on 01 Apr 2010).
“Introduction to Cephalopods“, by The Cephalopods Page. URL: http://www.thecephalopodpage.org (accessed on 01 Apr 2010).
“Octopus camouflage“, by oldenhaller. YouTube.com, 02 Feb 2008. URL: http://www.youtube.com/watch?v=jN99Kx_ghC8&feature=PlayList&p=59D36CEBC472A154&playnext_from=PL&playnext=1&index=30 (accessed on 01 Apr 2010).
“Malleable skin coloration in cephalopods: selective reflectance, transmission and absorbance of light by chromatophores and iridophores”, by Lydia M. Mäthger & Roger T. Hanlon. Springerlink, 05 Apr 2007. URL: http://www.springerlink.com.libproxy1.nus.edu.sg/content/b22635n5227245w6/fulltext.html (accessed on 01 Apr 2010).
“The Indonesian Mimic Octopus” by marcelnad. YouTube.com, 01 Feb 2008. URL: http://www.youtube.com/watch?v=H8oQBYw6xxc&feature=related (accessed on 01 Apr 2010).