The Wonderpus and Mimic Octopuses of Indonesia and Malaysia
Beautiful and Surprising Octopuses
The beautiful and amusingly named wonderpus octopus is a vividly patterned, long-armed creature that lives in the shallow ocean water around Indonesia and Malaysia. The animal is a popular photographic subject for divers and has the very apt scientific name of Wunderpus photogenicus.
The wonderpus octopus is usually orange-brown or red-brown in color, with sharply defined white spots on its body and white bars on its arms. The colors and pattern become more dramatic when the animal is alarmed. Its “head” is branched. There's a small eye on each branch and a tall, vertical protuberance called a papilla above each eye.
The wonderpus octopus is often confused with the mimic octopus (Thaumoctopus mimicus), which lives in the same general area and has a somewhat similar pattern of white spots and bands on a darker background. The background color of a mimic octopus is often dark brown or black, while the wonderpus octopus generally has a light brown background tinged with orange or red. The mimic octopus has the amazing and almost instantaneous ability to change its color, skin texture, arrangement of the arms around the body and style of movement in order to mimic other creatures.
The Wonderpus Octopus
The wonderpus octopus was officially recognized by scientists in 2006, while the mimic octopus was recognized in 1998. The ocean around Indonesia and Malaysia is proving to be very fertile ground for the discovery of new animals, some of which are spectacular.
The Body of an Octopus
Octopuses are invertebrates. Unlike most other invertebrates, they are intelligent creatures with a brain and a well developed nervous system. They also have excellent eyesight. Experiments have shown that at least some octopuses can learn and that at least some seem to like playing with objects. Sadly, they have very short lifespans—from six months in some species to just a few years in others.
Octopuses have soft bodies, although they do have a hard structure in their mouth called a beak. This looks quite similar to a parrot's beak. An octopus uses its beak to bite its prey. Its mouth contains a tongue-like structure called a radula which is covered by rasping denticles, or teeth.
An octopus's lack of hard, protective body parts could make it easy for predators such as large fish to attack it, so it needs camouflage techniques and the ability to move fast to protect itself. There is at least one advantage to having a soft body, though. It allows the animal to squeeze into tight spaces.
The mantle of an octopus is a thick layer of skin and muscle which forms a bag-like structure that covers the organs. These organs include the three hearts, the digestive, excretory and reproductive organs and the gills, which are used for breathing. The mantle moves as water flows under its edge and over the gills, where oxygen is extracted, and then leaves again. The water is sent out of the body through a tube called the siphon. An octopus can forcibly expel water out of the siphon, which provides jet propulsion and enables the animal to move very rapidly.
Octopuses have a poison gland that injects a toxin into their prey as they bite it. Researchers say that all octopuses are venomous but that most are not dangerous to humans. Octopuses also have an ink sac that can release a cloud of thick, dark "ink" to confuse potential predators.
The skin of octopuses contains a very high density of special cells called chromatophores, which contain pigments. The chromatophores are controlled by the nervous system. As the chromatophores expand and contract they enable octopuses to alter their color, or as in the case of the wonderpus octopus, to brighten and subdue the colors that are already present.
Wonderpus Octopus Escaping From Danger
Octopuses of some species have been observed performing complicated courtship displays, which often involve color changes. During mating, the male uses a special arm called a hectocotylus to insert a sac of sperm into the female's mantle aperture. The eggs are fertilized inside the female's body and then laid. Some females glue their eggs to the wall of a den and care for them until they hatch, but others, such as the female wonderpus octopus, attach the eggs to an arm and carry them around until they are ready to release the youngsters.
Octopuses belong to the order Octopoda, which contains two suborders. The information about octopus biology given above applies to the suborder Incirrata, which contains animals with the familiar body form of an octopus. The suborder Cirrina contains animals which have a slightly different body form and biology.
The Wonderpus Octopus
Since the wonderpus octopus has only recently been discovered by scientists, and since it doesn't live for long in captivity, there's still much that is unknown about its life. Its home is a burrow on the ocean floor. This may be a burrow dug by another animal or a burrow dug by the octopus. The animal emerges from its home to feed at dusk and at dawn. It moves by swimming or by using its arms to perform a walking motion over the ocean bottom.
The wonderpus octopus is a predator and feeds on fish, crabs and perhaps other animals as well. Two different methods of catching prey have been observed. The octopus may move over the top of a potential prey animal, expanding the webs attached to its eight arms to form an "umbrella" over the unfortunate animal and then pulling it towards its mouth with an arm and eating it. The octopus may also send one of its arms down into a hole like a probe, grabbing prey with the suckers on the underside of the arm. The wonderpus octopus has the ability to regenerate parts of arms that are lost and can deliberately release these parts to distract a predator.
Two theories have been proposed to explain why the wonderpus octopus developed its dramatic and conspicuous appearance. One theory suggests that the octopus is mimicking dangerous banded animals like sea snakes and lionfish as a form of protection against predators. Another theory says that it may be warning predators that it's toxic.
The Mimic Octopus
The mimic octopus's ability to mimic other creatures is truly astounding. So far it's been found to impersonate fifteen other animals, including fish, jellyfish, brittle stars, sea anemones, crabs, and shrimp. Furthermore, observations have shown that it chooses an appropriate animal to mimic in order to protect itself from a specific predator.
To mimic a poisonous flatfish, the octopus swims with its arms held together and streaming behind it and its body flattened. To mimic a toxic sea snake, it partially enters a burrow, leaving just two of its arms visible. It can swim in open water and change its movement style, suspending its arms in the water to resemble the dangerous fins of a lionfish. There are some claims that the wonderpus octopus also exhibits the latter two behaviors.
The mimic octopus can change its color and the texture of its skin to help make its impersonations effective. Some other octopuses can change color to merge with their background, but the mimic octopus is the first one known to mimic other creatures. Unlike the wonderpus octopus, the mimic octopus is active during the day, so its excellent ability to impersonate other animals is very helpful for its survival.
An Indonesian Mimic Octopus
Comparing the Mimic Octopus and the Wonderpus Octopus
Apart from its enhanced ability to change color and mimic other creatures, the behavior of the mimic octopus seems to be very similar to that of the wonderpus octopus. It eats the same types of animals and uses the same methods to catch its prey. In addition, the female attaches her fertilized eggs to her arms, just as the wonderpus octopus does.
It might seem that it should be easy to distinguish a wonderpus octopus from a mimic octopus by color. Color isn't a consistently reliable way to differentiate between the two animals, however. This is due to individual variability and the fact that the underwater appearance of the animals is affected by the type of illumination that's shining on them. The ability of the mimic octopus to change color can also make identification difficult.
There seems to be a lot of confusion when people try to distinguish one octopus from the other. Some of the observations that have been recorded about mimic octopus behavior may actually be observations of wonderpus octopus behavior and vice versa.
If the octopus is changing color in front of us we know that it’s a mimic octopus, but how else can we tell them apart, especially if a mimic octopus isn’t altering its color, texture or pattern? Some methods are described in the table below.
Mimic Octopus Behavior
Distinguishing a Wonderpus Octopus From a Mimic Octopus
Usually active in the early morning and in the evening
Usually active during the day
Separation between dark and light areas of skin is distinct
Separation between dark and light areas of skin is less distinct
Often has a light brown and white coloration
Often has a very dark brown and white coloration
Rear edge of mantle has a white spot
Rear edge of mantle has a white U or V shape
Eyes are on long stalks
Eyes are on shorter stalks
No white border on arm at base of suckers
White border on arm at base of suckers
The wonderpus and mimic octopuses are fascinating animals. It will be very interesting to see what else researchers learn about them. Perhaps there are even more strange creatures waiting to be discovered in the ocean near Indonesia and Malaysia!
© 2012 Linda Crampton
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